Dear Yin Ling Series
December 26, 2016 | Author: ssppalaniappan | Category: N/A
Short Description
Guide on less well known clinical features and symptoms. All credit goes to Dr Wong Yin Onn of Monash Uni, Malaysia....
Description
Q & A in Internal Medicine
Associate Professor Wong Yin Onn Clinical School, Johor Bahru, Monash University Malaysia
This eBook is a collation of questions that I ask my medical students at my Bedside teaching sessions. Dr Chok Yin Ling, a brilliant young doctor keen on a career in Internal Medicine, was given these questions on a daily basis. This was to help her to prepare for her post graduate examinations. These questions and answers were edited and documented in her digital diary; this eBook is the result. I hope that this work which is FREE to all will help students at both undergraduate and post graduate levels. I dedicate this eBook to all the teachers of this ancient art.
dr wong yin onn MBBS(Mal), MRCP (UK), AM, FRCP(Glas) 22 March 2014
Foreword by Dr Ng Kian Seng, the founder of Aequanimitas The Dear Yin Ling Series... The words are of course not to be taken literally... "Dear" is the heart attitude that Prof Punna Wong brings to his teaching, he loves his students... Yin Ling is a real name but of course it is also a metaphor for the HO, MO, Consultant, Medical student who is passionate for medicine and patient... please do not allow overworked, underpaid Yin Ling to be the sole person interacting with Prof Wong... think of that... I am also a Yin Ling (older, male and fatter version) and Prof Wong is also addressing me when he says, Dear Yin Ling...and Yin Ling should be proud that Prof Wong has used her name...as a metaphor I love the title and so do many of the people in Kluang and perhaps around the world!
Dear Yin Ling, Osler said that to succeed you must Have a Calling, The Calling to be the BEST Physician that you can be, the most compassionate doctor available, and the most dedicated student soaking up all that your seniors can teach. Even after he was well established in medicine, Osler was urged to consider other career paths eg university presidency and politics, but he always declined. Thank goodness for that. Politics would have killed him off early. In perhaps his greatest speech to a medical student body, titled “Aequanimatus,” he spoke of having found his calling. You must have the same calling that will push you to study till the wee hours, to see patients till you drop from exhaustion, to learn like your life depends on it, and hopefully to also teach your juniors like a woman possessed. “To prevent disease, to relieve suffering, and to heal the sick—this is our work. The profession in truth is a sort of guild or brotherhood, any member of which can take up his calling in any part of the world and find brethren whose language and methods and whose aims and ways are identical with his own."
Questions 1) ON H.PYLORI Dear Yin Ling, What can we use in HP resistant to Amox/clarythro/PPI combination treatment? The issue is what to do with treatment failures. The success rate for the current combination is assumed to be over 85%. It is likely that the success rates are gradually decreasing as macrolide resistance becomes more prevalent. There is some cross-‐resistance to clarithromycin from the use of other macrolides. After failure of a combination of PPI, amoxicillin and clarithromycin, a theoretically correct alternative would be the use, as second option, of other PPI-‐based triple therapy including amoxicillin (that does not induce resistance) and metronidazole (an antibiotic not used in the first trial). However in practice this approach as second-‐line treatment has proven to be disappointing (approx 50% eradication rate). Levofloxacin-‐based 'rescue' therapy appears to be the best second-‐line strategy, representing a good alternative to quadruple therapy in patients with previous PPI-‐ clarithromycin-‐amoxicillin failure – this treatment has higher efficacy, simplicity of use (better compliance) and less adverse effects. Levofloxacin has, in vitro, remarkable activity against H. pylori and primary resistance is relatively infrequent (when compared with metronidazole or clarithromycin). A combination of a PPI, amoxicillin and levofloxacin, as first-‐line regimen, has mean eradication rates of about 90%. For patients with one previous eradication failure, H. pylori cures rates range from 60% to 94%. A recent systematic review showed a mean eradication rate with levofloxacin-‐based 'rescue' regimens (combined with amoxicillin and a PPI in most studies) of 80%, which represents a relatively high figure when considering 'rescue' therapy will have have eradication rates lower than first-‐line treatments. A systematic review found higher H. pylori cure rates with 10-‐day than with 7-‐day regimens with the levofloxacin-‐amoxicillin-‐ PPI combination in particular (80% versus 68%), suggesting that the longer (10-‐ day) therapeutic scheme should be chosen. The daily dose is still unclear but 500mg daily may be as effective as 500mg bd.
Please check with Urea Breath Test post treatment for cure!
2) ON LIPIDS Dear yin ling, High cholesterol plus high Triglycerides is common clinical problem. Statins alone often do not return one to normal physiology. WHAT can you offer?
http://www.ncbi.nlm.nih.gov/m/pubmed/23324122/ Adverse events following statin-fenofibrate therapy versus statin alone: a metaanalysis of randomized controlled trials. Geng Q, et al. Journal Clin Exp Pharmacol Physiol. 2013 Mar;40(3):219-26. doi: 10.1111/1440-1681.12053.
Abstract The combination of fenofibrate with statins is a beneficial therapeutic option for patients with mixed dyslipidaemia, but concerns about adverse events (AEs) make physicians reluctant to use this combination therapy. Medline, Embase and the Cochrane Library were searched to identify 13 randomized controlled trials, involving 7712 patients, of statin-‐fenofibrate therapy versus statin alone for review. There were significant decreases in low-‐density lipoprotein-‐cholesterol, triglycerides and total cholesterol and increases in high-‐density lipoprotein-‐cholesterol in patients receiving combination therapy compared with statin therapy alone. The incidence of aminotransferase elevations in the fenofibrate-‐statin therapy group was significantly higher than in the statin monotherapy group (odds ratio (OR), 1.66; 95% confidence interval (CI) 1.17-‐2.37; P < 0.05). The incidence of elevated creatine kinase levels (OR 0.88; 95% CI 0.63-‐1.23; P > 0.05), muscle-‐associated AEs (OR 0.98; 95% CI 0.88-‐1.09; P > 0.05) and withdrawals attributed to liver and muscle dysfunction did not differ significantly between the two groups. The efficacy of fenofibrate + standard-‐dose statin and incidence of AEs in the fenofibrate + standard-‐dose statin group were almost identical to those in the fenofibrate-‐statin group. In conclusion, combination therapy improves the blood lipid profile of patients. Fenofibrate-‐statin combination therapy appears to be as well tolerated as statin monotherapy. Physicians should consider fenofibrate-‐statin combination therapy in patients but monitor aminotransferase levels to avoid hepatic complications. YL: i learnt that it's also important to realize that both alcohol and insulin resistance can give a high TG. insulin resistance caused the breakdown of triglycerides and release FFA. one dietary advice is to cut down simple carbs and sugars to control TG. TG will also increase SMALL, DENSE LDL particle, aka LDL3, which is highly atherogenic compared to LDL1 which is larger and less dense. we cannot measure both of them, hence the surrogate marker of high TG and low HDL reflects the
small and dense LDL3 particle. by controlling TG with a fibrate, we make the small dense LDL become bigger less dense LDL, and decrease the overall atherogenic risk, despite no change in LDL levels. We rarely use gemfibrozil now. Only fibrate and niacin increase one's HDL. but niacin makes one look like a crab-‐ flushing!! We may combine with using a statin at night and fenofibrate in the morning. PROF : Under what conditions will we still use gemfibrosil? Many of our patients on follow up have renal impairment of various stages. They are commonly monitored by eGFR which is convenient vs 24h urine for CCl. Fenofibrate increases creatinine levels significantly hence a calculated eGFR will be falsely lowered. Gemfibrosil avoids this effect. http://www.ncbi.nlm.nih.gov/m/pubmed/12372935/ Fenofibrate increases creatininemia by increasing metabolic production of creatinine. Hottelart C, et al.
Journal Nephron. 2002;92(3):536-41.
Abstract Fenofibrate is a potent hypolipemic agent, widely used in patients with renal insufficiency in whom dyslipidemia is frequent. A moderate reversible increase in creatinine plasma levels is an established side effect of fenofibrate therapy, which mechanism remains unknown. We have previously reported that in 13 patients with normal renal function or moderate renal insufficiency, two weeks of fenofibrate therapy increased creatininemia without any changes in renal plasma flow and glomerular filtration rate [1]. In 13 additional patients, muscular enzymes (AST, GPT, CPK, LDH) and myoglobin were measured before and after 2 weeks on fenofibrate, and the values of creatininemia obtained by the Jaffé technique and HPLC were compared. CPK and AST activity and plasma myoglobin increased in 2 patients with fenofibrate, but muscular enzymes remained unchanged in the population as a whole, and were not correlated to the changes in creatininemia. The changes in
creatininemia induced by fenofibrate measured by the Jaffé technique were strongly correlated to those measured by HPLC (r(2) = 0.675, p = 0.0006). Analysis of the pooled data of the two arms of the study showed in 26 patients that two weeks of fenofibrate therapy efficiently reduced total cholesterol and triglycerides plasma levels, and raised creatininemia from 139 +/-‐ 8 to 160 +/-‐ 10 micromol/l (p < 0.0001), but confirmed that creatininuria also increased to the extent that creatinine clearance remained unchanged (68 +/-‐ 6 vs. 67 +/-‐ 6 ml/min, n.s.). It is concluded that the increase in creatininemia induced by fenofibrate in renal patients does not reflect an impairment of renal function, nor an alteration of tubular creatinine secretion, and is not falsely increased by a dosage interference. Fenofibrate-‐induced increase of daily creatinine production is neither readily explained by accelerated muscular cell lysis. It is proposed that fenofibrate increases the metabolic production rate of creatinine. 3) ON CANTLIE’S LINE Dear Yin Ling, Who is Sir James Cantlie and why is his contribution not only to medicine but also to Asia and the world? Cantlie's line is named in his honour. What is this line and how is it so important to our understanding of the treatment of liver tumours? Everyday in my work I look out for diseases and carefully see if it is to the left or right of Cantlie's line and hence potentially treatable. Dr James Cantlie was a Foundation Professor at the primordial College of Medicine in HongKong (later to become the Faculty of Medicine at the University of HongKong). In his very first batch was a young brilliant Chinese lad named Sun Yat Sen. Teachers of old like some teachers today loved their students like their own children (following the Hippocratic oath the relationship is akin to a Father-‐ Son/Daughter bond). It was also in HongKong that he did his seminal work on the liver. Years later when Dr Sun Yat Sen the revolutionary was kidnapped by the Manchurian regime in London and almost definitely headed back home for his head to be separated from his neck, it was Sir James Cantlie that Dr Sun turned to for help and he organised a
press campaign and much publicity that ultimately pressured the Manchurian authorities to release Dr Sun, once again proving the power of the pen vs the sword. Dr Sun subsequently went on to be the Father of Modern China. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2826664/ Thomas M van Gulik and Jacomina W van den Esschert
Abstract As early as 1897, Sir James Cantlie published a series of observations of extraordinary significance in the face of how we now look upon portal blood supply and the pre-‐resectional use of portal vein ligation or embolization to induce hypertrophy of the part of the liver we intend to preserve. In the Proceedings of the Anatomical Society of Great Britain and Ireland, he describes performing an autopsy on a patient in which the right side of the liver was reduced to a mass of fibrotic tissue whereas the left side of the liver showed a marked hypertrophy.1* He noted ‘that the hypertrophy of the left side joined with the atrophied right side, at a line drawn through the fundus of the gallbladder to the center of the inferior vena cava at the back of the liver’. He assumed that an abscess had destructed the right lobe of the liver, and that this resulted in a compensatory hypertrophy of the contralateral part of the liver. Hence, he concluded that the line connecting the fundus of the gallbladder with the centre of the inferior vena cava indicated the mid-‐line of the liver, unlike common opinion at that time which considered the umbilical fissure as the division of the right and left liver lobes. He corroborated his observations by performing experiments in which he injected the right and left divisions of the portal vein with coloured dyes showing that the injected areas met along a line connecting ‘the fundus of the gallbladder’ with ‘the spot where the inferior vena cava grooves the back of the liver’. This line we still refer to as Cantlie's line (Fig. 1) indicating the anatomical mid-‐line of the liver and defining the border between the right and left liver segments in the plane of the middle hepatic vein. As he realized that the right and left liver were perfused by two separate streams of the portal vein, he recognized the potential this phenomenon could have for hepatic surgery.
Figure 1
Cantlie's line represents the anatomical mid-‐line of the liver connecting the fundus of the gallbladder with the centre of the inferior vena cava. He perceived the consequences the watershed between the right and left liver lobes could have for trauma of the liver by writing ‘The liver, when split or fissured by a blow, as between the buffers of railway-‐carriages, splits along the mid-‐line of the liver in preference to any other’. He also foresaw that this would not necessarily result in major bleeding as ‘haemorrhage has less to be dreaded as the liver is incised or torn in the neighborhood of that line (i.e the mid-‐line)’. Indeed in blunt abdominal trauma, the liver may be completely fractured along Cantlie's line without any major bleeding from that plane. We were able to confirm this message recently in a patient admitted after blunt abdominal trauma who had fractured his liver along Cantlie's line (Fig. 2) and who had been successfully managed by conservative treatment without the need for any blood transfusion.
Figure 2 Contrast enhanced abdominal computed tomography (CT) scan of a patient admitted after blunt abdominal trauma showing a fracture of the liver along Cantlie's line, running between the medial borders of segment IV and segments V/ VIII. Coming back to his initial observation at the autopsy, he noted the ‘almost elephantine’ hypertrophy of the left side of the liver at the expense of a greatly atrophied right side ‘which looked like, and practically was, a mere appendage to the left side of the organ’. On dissection of the liver he found the veins, artery and duct of the right side of the liver to be obliterated whereas those to the left side were proportionally increased in diameter. From this observation he conceived that by eliminating blood supply to one side of the liver, a functional advantage for the spared half of the liver could be created resulting in hypertrophy of that part of the liver. He then wrote ‘It is theoretically possible to tie the vessels of one side at the gate of the liver, supplying an abnormal growth in one or other of the liver lobes, leaving the other side to do the work’. Realizing the importance this phenomenon could have for resecting the liver, he continued ‘I commend this subject to all those who are working at the surgery of the liver; and I believe that if, in the hands of future observers, the statements I have made receive closer investigation, the surgery of the liver will be advanced a step’. The foresight he had was amazing, with the first formal right hemihepatectomy being performed 55 years later in Beaujon
Hospital in Paris and the first clinical portal vein embolization being performed in Japan 85 years after his report. Sir James Cantlie (Fig. 3) was born in 1851 in Banffshire, Scotland. After finishing his medical studies at Aberdeen University, he trained as a surgeon at Charing Cross Hospital in London. He became a fellow of the Royal College of Surgeons in 1877 and went on to work as a surgeon at Charing Cross. Interestingly, in 1887 he moved to Hong Kong where he became a co-‐founder of a new medical school, the Hong Kong College of Medicine for Chinese, the forerunner of the Faculty of Medicine of the University of Hong Kong. In this institution, of which he led the surgical department, Cantlie carried out the autopsy described above. One of his students was SunYat Sen who would later become the first provisional president of the Republic of China. When this Chinese leader was detained at the Chinese Legation in London in 1896, Cantlie played a key role in his release. In 1897 Cantlie returned to practice in London.
Figure 3 Sir James Cantlie (1851–1926) The division of the portal vein into a right and left branch at the liver hilum was already reported by the anatomists of the 17thcentury. Francis Glisson (1598–1677) in his textbook Anatomia Hepatis described cannulating the portal vein and making casts of the portal venous system. Cantlie, however, showed that by the separate portal vasculature, the liver could be functionally divided into an anatomically distinct right and left half. The potential of one half of the liver to hypertrophy when the other half is deprived of its blood supply was further confirmed in experimental studies by Rous and Larimore in 1920 and Schalm and colleagues in 1956. The latter authors from Arnhem, the Netherlands, made reference to Cantlie's work and ideas on unilateral occlusion of the portal vein. Surprisingly, portal vein occlusion found its way to clinical application only in 1982, when Makuuchi and later, Kinoshita, published their first experiences with portal vein embolization in patients. Hence, although the credit for the first clinical portal vein occlusions goes to these colleagues in Japan, it should be remembered that in 1897, James Cantlie from Scotland had already laid down the concept of pre-‐operative portal vein occlusion.
YL: Cantlie's Line delineates the SURGICAL anatomy of the liver, a line connecting the fundus of the GB and the IVC, separating the liver into the surgical Left and surgical Right lobe. while, the Falciform Ligament we see from the anterior aspect of the liver is just the anatomical line, nothing to do with its function nor help with surgery. You often look for the hepatic veins on USG while placing your probe subcostally. It's the one with thin walls as opposed to the thicker walls of the portal veins. The middle and right hepatic vein join the IVC, showing us the 'Playboy Sign'. A thin playboy if its normal. When you see lesions suspicious of HCC/mets, if they are on one side of the Cantlie's line, there is hope of tumour resection for the patient. if it crosses both lobes, unfortunately we will have to prepare the patient for the worst.
4) ON THALASSEMIA Dear yin ling, Yesterday a student told me that her mother has heavy menses and is chronically anaemic. Low ferritin confirmed. The student herself looked a bit pale too. I asked if she has any family history of Thalassemia. And she replied that Screening for Thalasaemia for her mother was done at the same time. And it is 'normal'. What are your concerns as a consultant on knowing this and what will you advise?
YL: Thalassemia cannot be screened when there is concurrent iron deficiency anemia.. HbA2 will be FALSELY NORMAL. We have to correct the iron deficiency first. Repeat ferritin-‐ normal range only then we can do a thalassemia screening. Prof : Iron deficiency is common in adult women. It is a serious potential complicating factor when testing for a thalassaemia carrier state. Both iron deficiency and a thalassaemia carrier state may result in a low MCV and MCH. But the MCV in thalasaemia is generally very low. Erythrocytosis is more likely to be caused by thalassaemia, but it is not a diagnostic finding. The diagnostic criterion for beta thalassemia trait (BTT) is elevated Hb-‐A2 levels. Iron deficiency anemia (IDA) reduces the synthesis of Hb-‐A2, resulting in reduced Hb-‐A2 levels, so patients with co-‐pathological conditions BTT with IDA, may have a normal level of Hb-‐A2. Many socio-‐economic factors like worm infestation, poor diet, multiple pregnancies, doctor unawareness result in interpretation of these subjects as simply iron deficiency anaemia or worse as normal. PROF : What is the danger of just giving iron to patients undiagnosed or misdiagnosed as iron deficiency? Tell me about Hepcidin and its role in iron physiology. What happens in Thalasaemia carriers? YL : Hepcidin regulates the iron absorption in our body. Hepcidin inhibits iron absorption. Low hepcidin encourage iron absorption and vice versa. When there is increase erythropoiesis.. hepcidin will be low so that absorption of iron is increased, and vice versa. During inflammation, hepcidin also an acute phase reactant is high, iron absorption is less so contributing further to anemia of chronic diseases.
Beta thal carriers do not have severe anemia but they have increase in erythropoiesis and low hepcidin levels. They can have iron overload from all the increased iron absorption. When we have not diagnosed iron deficiency anemia, giving iron to pt who has other diseases such as beta thal trait may cause iron overload! More so with their tendency to have an increased iron absorption. We are doing more harm than good to them PROF : It is uncommon to transfuse patients with BTT unless their Hb is unacceptably low. Most of them adapt very well to the chronic anaemia. Furthermore blood transfusion also transfuses iron besides the risk of blood borne diseases. Having said that I am aware of some BTT female patients who require blood transfusion. They likely have beta thalasaemia intermedia The term "thalassemia" is derived from the Greek root words for "anemia" and "sea" because the thalassemia syndromes were initially believed to be restricted to populations around the Mediterranean Sea In most adults, 97% of the hemoglobin produced is hemoglobin A (HbA), which has two alpha-‐globin chains and two beta-‐globin chains. The remaining 2% to 3% of adult hemoglobin is hemoglobin A2, which is composed of a pair of alpha-‐globin chains and a pair of delta-‐globin chains. In some adults, fetal hemoglobin HbF, which is composed of two alpha-‐ and two gamma-‐globins, may continue to be produced, but it does not typically exceed 2% of the hemoglobin production Thalassemia intermedia is a term to describe patients with beta-‐thalassemia in whom the clinical severity falls between the minor and major forms. The minor forms, tend to be clinically mild, if not asymptomatic There are two beta-‐globin genes controlling the production of beta-‐globin, one on each copy of chromosome 11. The beta-‐globin gene may have a mutation that results in the production of no beta-‐globin, noted as [beta]0, or it may have a mutation that results in reduced production of beta-‐globin, noted as [beta]+. Beta-‐ thalassemia trait occurs when a person acquires a normal beta-‐globin gene and a thalassemic beta-‐globin gene, or two thalassemic beta-‐globin genes that still produce minimal to moderate amounts of beta-‐globin chains Survival advantage The RBC in a patient with beta-‐thalassemia trait is more rigid and dehydrated than a normal RBC.
Due to similarities in the distributions of malaria and the thalassemias, it was hypothesized that the development of thalassemia traits offered some protection in malarial infection. Alpha-‐thalassemia may offer some general protection against severe malaria. Beta-‐thalassemic patients may be protected from malaria by an enhanced phagocytosis of the early intraerythrocytic form of malaria, called rings, in beta-‐thalassemic cells. Thalassemia trait may be manifested by pallor, fatigue, or other nonspecific complaints associated with anemia. There may be a family history of anemia; often it has been mistakenly diagnosed as iron deficiency. The family's ethnic origin may be suggestive of a thalassemia trait if they are from the Mediterranean region, or Southeast Asia. There is frequently a marked microcytosis, with a LOW mean corpuscular volume, and mild to moderate hypochromia of the RBCs. The characteristic RBC count index findings for beta-‐thalassemia trait are a high RBC count, mild anemia, and microcytic, hypochromic cells. The mean corpuscular hemoglobin concentration (MCHC) tends to remain in the normal range of values. Mild splenomegaly may be found in people with beta-‐thalassemia trait Diagnosing the thalassemia traits can be difficult because the lab values may mimic iron deficiency; there may even be concurrent iron deficiency. If a patient has a low MCV, a serum ferritin level should be obtained. If the ferritin is low, the iron deficiency should be corrected, and the MCV reinterpreted afterward. If the ferritin is normal, a hemoglobin electrophoresis will identify hemoglobins A, F, and a number of other hemoglobin variants, along with the estimation of the HbA2 level. People with an elevated level of HbA2 along with hypochromic, microcytic RBCs have a beta-‐thalassemia trait . If the HbA2 is borderline high to normal, it is likely that they have alpha-‐thalassemia or a combination of alpha-‐beta thalassemia. Alpha-‐thalassemia trait is often regarded as a diagnosis of exclusion because the hemoglobin electrophoresis does not definitively prove it is an alpha-‐thalassemia trait. The definitive testing for alpha-‐ thalassemia traits would be genetic testing that can determine the exact number of deletions of the alpha-‐globin genes. These tests, however, are expensive and not readily available. Please always remember that Iron deficiency may obscure the results of the hemoglobin electrophoresis if thalassemia trait is present as it falsely normalize the level of HbA2
Dear Yin Ling are you aware of experimental treatments in Thalassaemia offering a possible cure. The experimental treatments include inducing the body to produce fetal hemoglobin again as opposed to adult hemoglobin, and the introduction of gene therapy. The treatments currently being tried are bone marrow or umbilical stem cell transplants. Fetal hemoglobin changes to adult hemoglobin later in childhood. It was noted that infants born with sickle cell anemia showed no signs of sickling until the fetal hemoglobin was replaced. It was extrapolated that if a child with thalassemia could have their adult hemoglobin replaced by fetal hemoglobin once again, this would be beneficial. A search began to find a drug that could reverse the neonatal switch in hemoglobins. This would need to be a drug that changed gene regulation called a hypomethylator. A drug was found (5-‐azacyidine) that worked well but caused severe side effects. We await new drugs. It is hoped that eventually thalassemia will be treated by replacing the defective globin gene with a normally working gene Presently the treatment of choice is stem cell transplant. Healthy stem cells sources include bone marrow and umbilical cord blood from healthy donors. Umbilical cord blood is a more readily available source of stem cells. The recent movement of umbilical stem cell collection at births is building up banks of possible tissue matches. The goal of stem cell transplantation is similar to gene therapy, ie replace the defective blood cells found in thalassemia with healthy normal blood cells. As far as exams is concerned, no discussion will be complete without mention of treatment BEFORE conception. This is particularly important in high prevalence regions. Both parental genetic screening and preimplantation diagnosis from a single blastomere in in-‐vitro fertilization have totally changed the way of life in some countries with previously high numbers of children with thalassemia. Throughout the Mediterranean, education campaigns have taken place for entire countries, especially targeting secondary school teens. Education and free thalassemia clinics provide choices about birth control, mate selection, adoption, fetal testing, artificial
insemination by donor, and abortion. Even the conservative Greek Orthodox Church agreed to require that all couples applying for a marriage certificate be pretested for thalassemia carrier trait. Abortion, which was previously illegal, has become legal in pregnancies diagnosed with thalassemia. Needless to say such steps have their proponents and opponents. 5) Yin Ling, A 25-‐year-‐old Chinese woman was referred for review of her anaemia. She is pregnant – about 12 weeks gestation at the time of presentation. G1P0 Asymptomatic. Planned pregnancy. She was noted by her GP to be pale when she went for her UPT. She does not recall any family members who are pale or require regular transfusion. Her menses prior to pregnancy was unremarkable. She eats like a true Malaysian with a "see food, eat food" diet. No bleeding noted. Clinically she appears pale but no koilonychia or glossitis is noted. She is not jaundiced or sallor or have any abnormal facies. No splenomegaly. Her initial full blood count from her GP showed a microcytic, hypochromic anaemia (MCH, 25.6 pg/cell, MCV 68) with a haemoglobin of 10.2 g/dL. The GP had started ferrous sulphate tablets at 200 mg three times daily for 4 weeks and asked for a repeat full blood count when the tablets had finished. The repeat full blood count results show a deterioration of the anaemia as below. Haemoglobin 9.8: Platelets: 384 White cell count: 10100 MCH: 26 MCV 65 At this point the GP asked for a consult. Questions • Why did the iron tablets not help? • What is the significance of this result? • How might you explain the different results for the two full blood counts? What will you do now for this patient?
Prof : Dear yin ling, dietary iron comes in different forms, the percentage of dietary iron absorbed depends on the type of food we eat and what other foods are being eaten at the same time. For example, iron from meat is easier for the body to absorb than iron from vegetable. In addition, iron absorption can be greatly increased or decreased by various factors. Chemicals called polyphenols in tea, coffee, cocoa, spinach inhibit iron absorption as well. Eating more ascorbic acid, which is common in fruits, vegetables and fortified foods, can improve iron absorption. But Calcium inhibits the absorption of iron by an unknown mechanism. This is probably why there is a correlation between high milk intake and iron deficiency. If indeed this patient or any patient has Fe def, then they should have iron supplementation both to correct anaemia and replenish body stores. This is achieved most simply and cheaply with ferrous sulphate 200 mg three times daily although ferrous gluconate and ferrous fumarate are as effective.
Elemental iron is the iron available in the supplement for absorption Ascorbic acid enhances iron absorption and can be given together. Patients often ask for injections instead! But Parenteral iron should only be used when there is true intolerance to oral preparations. It is painful (when given intramuscularly), expensive, cause the bum to have a BLACK spot and may cause anaphylactic reactions. AND The rise in haemoglobin is no quicker than with oral preparations!!! So why take the risk! The haemoglobin concentration should rise by 2 g/dl after 3–4 weeks. Iron from meat, poultry, and fish (i.e., heme iron) is absorbed two to three times more efficiently than iron from plants (i.e., non-‐heme iron).
The amount of iron absorbed from plant foods (non-‐heme iron) depends on the other types of foods eaten at the same meal. Thats why we eat a mixture of dishes.Foods containing heme iron (meat, poultry, and fish) enhance iron absorption from foods that contain non-‐heme iron (e.g., fortified bread, spinach). Foods containing vitamin C also enhance non-‐heme iron absorption when eaten at the same meal. Fruits at end of meal is important. Substances (such as polyphenols, phytates, or calcium) that are part of some foods or drinks such as tea, coffee, whole grains, legumes and milk or dairy products can decrease the amount of non-‐heme iron absorbed at a meal. Drink Chinese tea in small amounts during your meal, good tea is sipped right?! Not gulped. Calcium decrease the amount heme-‐iron absorbed at a meal. However, for healthy individuals who consume a variety of food, the amount of iron inhibition from these substances is usually not of concern. Vegetarian diets are low in heme iron. Medicines for peptic ulcer disease and acid reflux taken long term like some poor teachers here for chronic stress induced gastritis reduce the amount of acid in the stomach and the iron absorbed and cause iron deficiency. Thats the price we pay for teaching! This case scenario is complicated by the facts that 1. She is pregnant 2. She is not menstruating Because of rapid growth, infants and toddlers need more iron than older children. A student above is worried about the parasite called Ancylostoma duodenale. I am more concerned about a MUCH2 bigger parasite called FOETUS! Women who are pregnant have higher iron needs because of this. To get enough, most women must take an iron supplement in pregnancy. Serum iron. This test measures the amount of iron in the blood. BUT The level of iron in the blood may be normal even if the total amount of iron in the body is low. For this reason, a serum iron test is not adequate. Serum ferritin. Ferritin is a protein that helps store iron in the body. Its a BIG magnet
that sticks many Fe molecules but its also an inflammation associated molecule. Remember Cytokine storm in Dengue and what we must measure? Se FERRITIN!!!! A measure of this protein in the serum helps find out how much of the body's stored iron has been used or left. Se ferritin reflects the total body ferritin values. Transferrin level, and total iron-‐binding capacity. Transferrin is a protein that carries iron in the blood. Its like the lorries that carry this heavy metal round and round without it falling off and damaging all the roads. Total iron-‐binding capacity measures how much is the total capacity of the transferrin in the blood is there to carry iron. If the patient has iron-‐deficiency anemia, he/she will have a high level of transferrin, a high Total Fe carrying capacity aka TIBC that has ironically no iron. (hehe IRONically) So what should we use for screening, and what do we use when trying to diagnose a cause of anaemia? For GP screening, se ferritin is easily available and affordable. For diagnostic work up, the iron studies PLUS Folic acid levels PLUS Vit B12 and TSH is needed. The most useful Ix at workup is actually a PBF read by a competent haematologist. The answer is almost always there. Hemosiderin is an abnormal microscopic pigment composed of iron oxide and can accumulate in different organs in various diseases. Iron is toxic when not properly stored. Humans store iron within ferritin. The form of iron in ferritin is Iron(III) oxide-‐ hydroxide. By complexing with ferritin, the iron is made water soluble! Several diseases result in deposition of Iron(III) oxide-‐hydroxide in tissues in an insoluble form. These deposits of iron is hemosiderin! These deposits often cause no symptoms, but they lead to organ damage. Hemosiderin often forms after bleeding into an organ. When blood leaves a ruptured blood vessel, the hemoglobin of the red blood cells is released into the extracellular space. The macrophages phagocytose the hemoglobin to degrade it, producing hemosiderin and porphyrin. The iron in haemosiderin cannot be released for use. Its stuck! YL: after a month's treatment with iron supplement and assuming she is taking her iron tablets, she is still having microcytic hypochromic anemia with an MCV of 65, MCH of 26, low normal MCHC, normal RBC and normal RDW! We don't know the Se Ferritin and TIBC nor serum iron so far. RDW is a quantitative measurement of anisocytosis on PBF. it tells us that the RBC
production is haywired and a high RDW reflects a nutritional anemia. RDW helps us differentiate thalassemia and IDA for microcytic anemia; and vitamin B12/folate deficiency (megaloblastic anemia) from other macrocytic but NON megaloblastic anemia, hence its importance. in thalassemia the production of RBC is generally still OKAY, although they are abit small, hence the normal RDW. In this patient, a normal RBC and low normal MCHC, coupled on with a normal RDW, we really couldn't strike thalasemia off, moreover she's pregnant! So in view of a microcytic hypochromic anemia that is not correctable and also a FBC components which suggest something other than IDA, i would run iron panel tests to correct whatever iron deficiency anemia there is, and proceed to work her up for thalasemia. Beta Thalassemia trait can be easily pick up by Hb electrophoresis, while alpha thal needs a molecular diagnosis (as all Hb has an alpha component, on electrophoresis one low all low!) it is important to pick up alpha thal, a disease that is caused by gene deletion. if this patient happened to be a carrier/ minor, it is even more important to screen her husband too! the scariest thing about alpha thal is for the mother to have an aa/-‐ -‐ gene makeup which have the likelihood to couple up with a similar aa/-‐ -‐ gene makeup carried by her husband.............and produce a hydrops in her pregnancy.
Prof : The normal physiological increase in plasma volume in pregnancy causes haemodilution and can give an artificially low haemoglobin level. However, haemoglobin levels should not fall below 11.0g/dL and less than 10.5g/dL is abnormal. We often ASSUME that a microcytic, hypochromic anaemia esp in pregnancy is caused by a lack of iron. However, this patient is not iron deficient. Her se ferritin when tested is normal. Thalassaemia carriers are well, normal looking people but in females with heavy menses or during pregnancy are often anaemic, sharing the features of iron deficiency of microcytosis and hypochromia. A careful look beyond the FBC at the PBF will tell us the answer because the PBF is very characteristic. Another distinguishing element is the erythrocyte count which is reduced with iron deficit, but often increased in thalassaemia carriers. Her partner/husband/boyfriend needs urgent testing for haemoglobinopathies in order to estimate the risk to the fetus. If the partner tests positive the couple can be offered fetal testing to determine how the child might be affected, as for the fetus there is a one in two chance of being a carrier of haemoglobinopathy and a one in four chance of being either affected by the disease or free of the genetic disposition. Excluding the possibility that the baby’s father is a carrier of a haemoglobinopathy allows everyone to relax. A very low MCV/MCH must trigger testing for haemoglobinopathies.
KEY POINTS • Watch out: not all microcytic, hypochromic anaemias as seen in the FBC is caused by iron deficiency. • Test results in pregnancy have a different significance compared with tests for those not pregnant. For one you the doctor is dealing with a few lives! Prof : The pathogenesis of anemia of chronic disease is multifactorial and is related to hypo-‐activity of the bone marrow, with relatively inadequate production of erythropoietin or a poor response to erythropoietin, as well as slightly shortened red blood cell survival. The hallmark ferrokinetic profile of anemia of chronic disease is decreased serum iron level, decreased transferrin level, or normal or elevated ferritin levels, all of which result in iron being present but inaccessible for use. Do not forget Endocrine deficiency states, including hypothyroidism, adrenal or pituitary insufficiency, and hypogonadism, which may cause secondary bone marrow failure because of reduced stimulation of erythropoietin secretion. Hyperthyroidism may also cause normocytic anemia.
Anemia occurs in acute and chronic renal failure. The anemia is usually normocytic but may be microcytic. In renal failure, anemia occurs in part because uremic metabolites decrease the lifespan of circulating red blood cells and reduce erythropoiesis. Anemia secondary to uremia is characterized by inappropriately low erythropoietin levels, in contrast to the normal or high levels that occur with most other causes of anemia. To further confuse the presentation, serum iron levels and the percentage of iron saturation are often low. Furthermore, the serum creatinine level and the degree of anemia may not correlate well. And never forget abt RETICULOCYTES! ! They falsely increase mcv. Remember that the role of the consultant is TO BE CONSULTED WHEN OTHERS HAVE DIFFICULTY SOLVING A PUZZLE. So one must think laterally. When the HO or MO is stuck it is usually because they are thinking along one line and NOT SEEING THE FOREST. JUST THE TREE Prof: Yin Ling, You know that in thalassemia minor/trait, patients tend to have elevated RBC count (>5.5) with low mcv and mch. What is the pathophysiology behind this? What does this lead to clinically? When a patient has a type of thalassemia, there is an excess production and accumulation of globin chains produced by genes that are not effected by the thalassemia deletion. This is a compensation mechanism that the body utilizes to maintain hemoglobin production. For eg In alpha thalassemia, the body can produce excess gamma chains as a compensatory mechanism. This can lead to the production of gamma chain tetramers (hemoglobin Bart's) in the unborn child and as beta chain tetramers (hemoglobin H) in adults. This subsequent tetramer accumulation in response to thalassemia often leads to red blood cell damage and hemolytic anemia. The normal or high RBC count results from MASSIVE FACTORIES in bone marrow producing RBCs desperately in response to chronic anaemia. Together with the decreased MCV this are indicators of ineffective erythropoeisis.
The RBC morphology shows hypochromic microcytosis with schistocytes, target cells, anisopoikilocytosis and basophilic stippling. Schistocytes form by several mechanisms, one being the removal of RBC inclusions. The splenomegaly is consistent with increased RBC destruction. Yin ling, Pls remember the following rules: (1) Thal trait rarely causes anemia of less than 10 g/dL. (2) The RBC count in TT is more than 5.0 x 106/μL (5.0 x 1012/L) and in IDA is less than 5.0 x 106/μL (5.0 x 1012/L). (3) The RDW in IDA is more than 17% and in Thalassaemia Trait is less than 17%. BUT THE MOST IMPT AND SIMPLE TEST IS A PBF! In Thalassaemia Trait it looks like a ZOO with all the various cells noted above. In IDA the RBCs are like Minions.... ALL SMALL PALE AND CUTE. As iron-‐deficiency anemia progresses, and the patient’s serum iron drops lower and lower, each successive wave of new red cells gets smaller and smaller. So there are some kind of small cells, and some really small cells! Smaller and smaller minions as each batch is released. The red cell distribution width (RDW) is high in iron deficiency anemia because there is now a wide variation in red cell size. In mild thalassemia (alpha or beta), the red cells are all about the same size; while they are weird looking they are in every batch similarly weird! ! Hence there is virtually minimal variation. So the RDW is normal. This difference in RDW is helpful when you’re trying to differentiate IDA and thalassemia; if you have a microcytic, hypochromic anemia, the next thing you’d do is look at the RDW (and pls3 look at the blood smear). If the RDW is normal (the cells are mostly the same size), then it’s probably thalassemia. If the RDW is high (the cells vary a lot in size), then it’s probably iron deficiency anemia.
6) on GROSSLY DAMAGED SMALL JOINTS OF THE HANDS Dear yin ling, There is an elderly lady who came to me with grossly damaged small joints of both hands. Symmetrical. Mark ventral subluxation of both hands at the wrist joints is seen. There is also prominent ulnar deviation in both hands and her fingers look small and flail. There is no warmth or swelling by the time I saw her. Her fingernails have onycholysis. The rest of her skin is normal. Her knees, feet and hips are normal. Her elbows cannot be fully extended. Her blood tests do not show any evidence of inflammation. RA factor negative. What are your thoughts? Does ROADS mean anything? Prof : Psoriatic arthritis usually occurs with skin psoriasis. People with psoriasis may also have changes in their fingernails and toenails, such as nails that become pitted or ridged, crumble, or separate from the nail beds. Signs and symptoms of psoriatic arthritis include stiff, painful joints with redness, heat, and swelling in the surrounding tissues. When the hands and feet are affected, swelling and redness may result in a "sausage-‐like" appearance of the fingers or toes (dactylitis). In most people with psoriatic arthritis, psoriasis appears before joint problems develop. Psoriasis typically begins during adolescence or young adulthood, and psoriatic arthritis usually occurs between the ages of 30 and 50. However, both conditions may occur at any age. In a small number of cases, psoriatic arthritis develops in the absence of noticeable skin changes. Psoriatic arthritis may be difficult to distinguish from other forms of arthritis, particularly when skin changes are minimal or absent. Nail changes and dactylitis are two features that are characteristic of psoriatic arthritis, although they do not occur in all cases. Psoriatic arthritis is categorized into five types: (D)distal interphalangeal predominant, (O)asymmetric oligoarticular, (R)symmetric polyarthritis, (S)spondylitis, and (A)arthritis mutilans.
Now yin ling pls makes a word with these capital letters like how PNEIS is made into SPINE. ROADS! The distal interphalangeal predominant type affects mainly the ends of the fingers and toes like SLE. Nail changes are especially frequent with this form of psoriatic arthritis. The asymmetric oligoarticular and symmetric polyarthritis types are the most common forms of psoriatic arthritis. The asymmetric oligoarticular type of psoriatic arthritis involves different joints on each side of the body, while the symmetric polyarthritis form affects the same joints on each side like RA. Any joint in the body may be affected in these forms of the disorder, and symptoms range from mild to severe. Some individuals with psoriatic arthritis have joint involvement that primarily involves spondylitis. Symptoms of this form of the disorder involve pain and stiffness in the back or neck, and movement is often impaired. Joints in the arms, legs, hands, and feet may also be involved. The most severe and least common type of psoriatic arthritis is called arthritis mutilans. Fewer than 5 percent of individuals with psoriatic arthritis have this form of the disorder, UNFORTUNATELY this patient has this. Her clue was in her extensive nail changes not seen in RA. Arthritis mutilans involves severe inflammation that damages the joints in the hands and feet, resulting in deformation and movement problems. Bone loss (osteolysis) at the joints may lead to shortening (telescoping) of the fingers and toes. Neck and back pain may also occur but thankfully she was spared. How common is psoriatic arthritis? Between 5 and 20 percent of people with psoriasis develop psoriatic arthritis. Some suggest a figure as high as 30 percent. Psoriasis itself is a common disorder, affecting approximately 2 to 3 percent of the population worldwide. Exam Q.... What genes are related to psoriatic arthritis? The specific cause of psoriatic arthritis is unknown. Inflammation occurs when the
immune system sends signaling molecules and white blood cells to a site of injury or disease to fight microbial invaders and facilitate tissue repair. When this has been accomplished, the body ordinarily stops the inflammatory response to prevent damage to its own cells and tissues. Mechanical stress on the joints, such as occurs in movement, may result in an excessive inflammatory response in people with psoriatic arthritis. The reasons for this excessive inflammatory response are unclear. Changes in several genes that may influence the risk of developing psoriatic arthritis. The most well-‐studied of these genes belong to a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders. Each HLA gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. Variations of several HLA genes seem to affect the risk of developing psoriatic arthritis, as well as the type, severity, and progression of the condition. Now in the OSCE situation, after you had diagnosed what assessment must follow? This is the critical part. Any doctor worth his her salt can diagnose but the MRCP winner must have this crucial next step. I will fail the candidate if this is not done properly. When the MCP PIP and DIP are all involved think of psoriatic arthropathy When there is arthritis and funny nails think of it too. When the hands are literally destroyed think of it too. RA destruction has the classic features. This looks like its nuked. Dear yin ling Your answer is good for membership exam but still incomplete. Remember I tried so very hard to teach the 4 aspects of diagnosis. What are they? Uncle kian seng added the 5th aspect which is CRUCIAL to flying at MRCP exams! This is the emotional toll of psoriatic arthritis! On top of evaluation of function. While most chronic illnesses increase stress, the emotional toll of psoriatic arthritis can very high. Not only do patients with psoriatic arthritis feel embarrassed because of the skin psoriasis, but the joint pain, stiffness, and fatigue make it near impossible to feel positive and be active. NHS guidance on psoriatic arthritis tells doctors to screen patients for emotional problems! !! Never forget these 2 things; FUNCTION AND EMOTION. In the ideal world this of course would apply for all patients of all illnesses.
YL : 4 aspects of diagnosis is Anatomical, pathological, aetiological and functional. 5th one would be emotional. Prof: Dr David KL Quek reports a patient worth a lesson to all of us A few years ago a 74 yr old man with extensive psoriasis but moderate polyarthritis presented with STEMI and acute pulmonary edema. We treated his acute heart failure then stented the culprit artery of his 3 vessel CAD. Then we got on to talking about his skin and joint disease and was shocked to hear that he'd not ventured out of his home for 5 years because of shame over his previously untreatable and 'ugly' skin condition! We got a dermatologist in who finally managed to get his psoriasis under control! Here for MRCP candidates to remember is that someone with a chronic inflammatory disorder can be predisposed to a higher risk of CAD. Methotrexate when used in treating psoriasis also predisposes the patient to higher thrombotic events. So you absolutely right that we need to more routinely gauge assess the emotional and psychological components and needs if our patients! 7) on BAD TONSILS! Dear Yin Ling, A 17-‐year-‐old school girl came with her mother. One week previously she had been seen by a GP and was diagnosed with acute tonsillitis. The doctor noted a history of sore throat, malaise, muscle aches all over the body, shivering, swelling around the eyes and headaches. Her mother was very anxious as she wants her well asap to study! The examination then revealed a temperature of 39.6C, pharyngitis, red, purulent and enlarged tonsils, and cervical lymphadenopathy. The doctor prescribed a 5-‐ day course of ampicillin and advised the patient to increase her fluid intake, rest and take regular panadol. The mother is concerned because her daughter has not recovered. She angrily related that at first the antibiotics seemed to help and the temperature, sore throat and headaches improved. But after 4 days a faint non-‐itchy red rash developed. While the pain in the throat is better, the patient complains of more pains in her
neck and the recurrence of headaches. She feels total lack of energy and mother is concerned that her daughter sleeps 18 hours a day. Mother is concerned about not having the energy to study for her upcoming exams. On examination she looks pale, unwell with a slightly yellow sclera. Her temperature is 37.6C. There are multiple swollen and tender lymph nodes in the anterior and posterior cervical regions, bilaterally. Her throat is still inflamed, and the tonsils enlarged, but without white patches. Some petechiae is seen on the soft palate. There is a faint red macular rash all over her trunk spreading to the limbs. The tip of the spleen is palpable on deep inspiration, the liver 2 FB palpable.
• What is the likely diagnosis and differential diagnosis? • What tests would you order? What will you do while awaiting the blood tests? Prof: Often the cervical LNs is BIG and parents worry about a malignancy. If the tonsils look as though a madman had painted whitewash on it, I am reasonably confident but if tonsils are mildly inflamed and with LNs and hepatosplenomegaly, I too worry about an Acute Haematological pathology. A PBF is very useful, often an experienced Pathologist will pick up Infectious Mononucleosis. IM aka Glandular fever is the most likely clinical diagnosis as many of you all realised. Acute tonsillitis is seen far more commonly in primary care and would have been a disease susceptible to antibiotic treatment although the rash may have been triggered by the antibiotic or may be from the illness itself. The further list of potential diagnoses includes acute Human immunodeficiency virus (HIV) infection, old friend diphtheria, cytomegalovirus and leukaemia.
The Paul–Bunnell reaction (Monospot) – heterophile immunoglobulin M (IgM) antibodies agglutinating sheep erythrocytes – is the most commonly used screening test for glandular fever. It can be falsely negative, especially in young patients, or falsely positive, for example owing to cytomegalovirus; so its not very good. A full blood count should show a leucocytosis between 10000 and 20000 cells/mm3, thrombocytopenia (often), and on the blood film many atypical activated T-‐lymphocytes (mononucleosis cells). More than 20 per cent atypical lymphocytes or more than 50 per cent lymphocytes with at least 10 per cent atypical lymphocytes on blood film make the diagnosis very likely.
There are more specific immunological tests for Epstein–Barr virus available which can be useful if the Paul–Bunnell test is negative and we still suspect the disease but its academic because by the time the results are back its already recovery time.
Glandular fever (infectious mononucleosis, or kissing disease) is an infection of the B-‐lymphocytes by the Epstein–Barr virus. It is a self-‐limiting disease. The virus is secreted in the saliva and can be transmitted through kissing or sharing utensils (cups, cutlery, towels). The organism may also be shed from the uterine cervix, implicating the role of genital transmission in some cases and possibly Oral Sex! On rare occasion, EBV is spread via blood transfusion. The incubation period is 4–8 weeks. Most patient recover within 2 weeks with some residual tiredness for another week. However, a significant minority go on to suffer with tiredness for much longer. It is reassuring to the doctor, patient and relatives to have the diagnosis confirmed. She needs to avoid contact sport because of the potential for damage to her swollen spleen, for 1–2months. She should see herself as infectious while she is feeling unwell, avoiding sharing utensils and close bodily contact. KEY POINTS • Early presentations of disease can be deceptive, with the correct diagnosis emerging later in its progression. • Proper diagnosis and sensible advice are reassuring for the patient and their family, whether or not there is effective medical treatment as the differentials are not too nice folks. Dear Yin Ling, Circulating B cells spread the infection throughout the entire reticular endothelial system (RES), ie, liver, spleen, and peripheral lymph nodes. Thats why they are Enlarged!! Easy to remember. EBV infection of B lymphocytes results in a humoral and cellular response to the virus. The humoral immune response directed against EBV structural proteins is the basis for the test used to diagnose EBV infectious mononucleosis. However, the T-‐ lymphocyte response is essential in the control of EBV infection; natural killer (NK) cells and predominantly CD8+ cytotoxic T cells control proliferating B lymphocytes infected with EBV.
In HIV patients we can well understand why the EBV goes berserk! The T-‐lymphocyte cellular response is critical in determining the clinical expression of EBV viral infection. A rapid and efficient T-‐cell response results in control of the primary EBV infection and lifelong suppression of EBV. Ineffective T-‐cell response may result in excessive and uncontrolled B-‐cell proliferation, resulting in B-‐lymphocyte malignancies (eg, B-‐cell lymphomas). The immune response to EBV infection is fever, which occurs because of cytokine release consequent to B-‐lymphocyte invasion by EBV. Lymphocytosis observed in the RES is caused by a proliferation of EBV-‐infected B lymphocytes. Thats why the lymphocyte count goes up and you have funny looking cells. At least to me la) Pharyngitis observed in EBV infectious mononucleosis is caused by the proliferation of EBV-‐infected B lymphocytes in the lymphatic tissue of the oropharynx. Now you know why the tonsils which is effectively 2 Big LNs look like a warzone. Pearls: fatigue is almost invariable! Pls note this symptom. Pulmonary involvement is not a prominent feature of EBV infectious mononucleosis. If the patient is badly hacking his/ her lungs away, ITS NOT IM! Jaundice occurs because of the hepatitis. Pls note yin ling that a POSITIVE THROAT C&S for Strep may mean NOTHING! as approximately 30% of patients with EBV infectious mononucleosis have group A streptococcal carriage of the oropharynx. The unwary physician may incorrectly conclude that a throat culture for group A streptococci in a patient with infectious mononucleosis represents streptococcal pharyngitis. EBV infectious mononucleosis is characterized by early and transient bilateral upper-‐lid edema but this is not a common sign. The external eye involvement of EBV infectious mononucleosis is characterized by bilateral upper-‐lid edema. This is referred to as Hoagland sign. Hoagland sign may be detected when patients look in the mirror early in the course of their illness or when the astute physician notices this early in the clinical presentation. Hoagland sign is present for only the first few days of illness and
should not be sought later in the course of the infectious process. EBV is the main cause of malignant B-‐cell lymphomas in patients receiving organ transplants. The Immunosuppression is Heaven for the virus! Depending on the intensity, rapidity, and completeness of the T-‐lymphocyte response, malignancy may result if EBV-‐induced B-‐lymphocyte proliferation is uncontrolled. Hodgkin disease and non-‐Hodgkin lymphoma (NHL) may result. Other EBV-‐related malignancies include oral hairy leukoplakia in patients with HIV infection. Leiomyomas and leiomyosarcomas in immunocompromised children, nasopharyngeal carcinoma, and Burkitt lymphoma are among other neoplasms caused by EBV.
8) on METFORMIN Dear yin ling, you asked me yesterday to viva you on Metformin and its usage in various clinical scenarios. I post here a few common Qs on Metformin.
This chart is impt as it shows the relationship between stress causing HIGH Glucose which cannot be cleared by low Insulin!! and with increase of shunting to lactate now made worse by poor clearance.
Dear YL, We no longer use Phenformin. But it has unjustifiably given Metformin a bad name. Metformin is actually a very safe drug when used mindfully. Under what conditions does Lactic acidosis occur? You run marathons, it is impt that you understand this. Can you describe how you felt like when lactic acidosis occured? Do you recall not having much appetite despite running such a long distance, anorexia is common. Were you nauseated, perhaps even vomiting? You felt deliriously happy when you finished but this altered level of consciousness could be due to metabolic cause!!! Yes you had hyperpnoea, abdominal pain and thirst. And I recall you telling me that you were anuric and had DARK urine! Please dun do it again!!! Red blood cells produce lactic acid as a byproduct of the regeneration of ATP during anaerobic glycolysis but cannot use lactic acid Take home that when you have a patient with tissue underperfusion and hypoxia coinciding because of illness or surgery, avoid Metformin! Lactic acidosis is a broad-‐anion gap metabolic acidosis caused by lactic acid overproduction or underutilization. The ABG and simple maths will tell you this. Overproduction of lactic acid occurs when the body must regenerate ATP without oxygen (tissue hypoxia). Circulatory, and pulmonary disorders are commonly responsible. Underutilization involves removal of lactic acid by oxidation or conversion to glucose. Liver disease, inhibition of gluconeogenesis by metformin!! are common causes. Poor renal function also makes excretion poor. Approximately 1400 mmol of lactic acid are produced daily, which are buffered by 1400 mmol of HCO3 to form sodium lactate. The liver is responsible for oxidizing lactate to restore this amount of HCO3. The role of the liver in lactate homeostasis is considerable. The kidneys contribute to lactate removal in three ways: excretion, gluconeogenesis, and oxidation.
Malignant cells produce more lactate than normal cells, even under aerobic conditions. This phenomenon is enhanced if the tumor outstrips the blood supply!!
Yin ling, Pls note the word STABLE! Problem starts when Renal function is deteriorating or is expected to deteriorate but NOT in the awareness of the HO. No one will use it when eGFR is less than 30 or you are walking a thin line. Tell me what common conditions can lead to a clinical deterioration of renal function? Ninety percent of metformin is excreted unchanged by the kidneys and lactic acidosis typically occurs in patients with renal insufficiency. Even mild renal disease increases the risk of lactic acidosis. Prof: A metformin dosage of 850mg twice a day, or 500mg three times a day, usually gives good diabetic control. There is not much point giving beyond 2000mg a day. Caution is needed when increasing the daily dosage beyond this, especially in the elderly and those with mild renal disease. Significant mortality ( as high as 50%) is associated with biguanide-‐induced lactic acidosis and attention should be focused on prevention through awareness of the risk factors.
Heart failure and metformin remains a bit confusing. I have seen papers which propose that it is not anymore dangerous than usual. Again the word is STABLE vs UNSTABLE. A patient who comes in with fluid overload and low O2 sat is different from one who is comfortable at home well maintained on medicine and stable. Someone who comes in with mild illnesses like a URTI is obviously different from another with severe pneumonia. Someone coming for excision of an in grown toenail is different from an elderly woman going for a total hip replacement. What will you do if you are refered such diabetic patients as above? YL: For the short term stay in hospital for unstable patients, sliding scale will be a good choice. Until we know patient is more stable and taking orally well, we will keep them on either sliding scale or regular insulin first PROF: Can you pls elaborate on the Sliding Scale used here? YL: We give pt subcut short acting insulin injection based on their blood glucose level every 4 hourly. The ranges can be 2 units of insulin if glucose is 5 to 10, 4 units for 10 to 15 and so on. Sliding scale can be augmented if glucose is hard to control.
Lactic acidosis is an uncommon but potentially fatal adverse effect. The reported frequency of lactic acidosis is 0.06 per 1000 patient-‐years, mostly in patients with predisposing factors. Examples of metformin-‐induced lactic acidosis scenarios include: A 69-‐year-‐old man, with renal impairment and cardiac failure, was prescribed metformin due to failing glycaemic control on glibenclamide monotherapy. He was well for six weeks, then developed lactic acidosis and died within 3 days. Tell me what should have been done if we can turn back the clock? An elderly man had a total hip replacement. Post-‐surgical lactic acidosis caused the death of this 70-‐year-‐old man whose metformin was not withdrawn at the time of surgery. If you are the resident, what would you have done instead? A 56-‐year-‐old woman, with no predisposing disease, died from lactic acidosis following major abdominal surgery for Ca Colon. Metformin was withdrawn only for the day of surgery. What should you have done instead if asked to see this patient? The risk factors for metformin-‐associated lactic acidosis include sepsis, high dosage, increasing age, and DEHYDRATION. The last is often forgotten! In situations predisposing to dehydration such as FASTING for surgery, or contrast radiography, metformin should be ceased at least 48 hours prior to the procedure (or on admission for an emergency procedure). It is not restarted until the patient has fully recovered and is eating and drinking normally. The glucose levels of patients in CATABOLIC states, e.g. sepsis or in the post-‐operative period, should be monitored and Short-‐term insulin therapy is strongly advised for Mx. Try not to use above 70 years old, and if using be very careful with renal function. remember that by the time biochemistry is abnormal, the renal function is already significantly affected bec of renal reserve YL: For the first scenario, his renal impairment already stop us fr using metformin. Pairing up with a heart failure causing increase tissue hypoxia, lactic acidosis is likely. Glibenclamide is such a long acting SU, hypo episodes is risky. And glibenclamide which shouldnt be use in renal impairment. We can use gliclazide.. a newer gen SU, lesser hypo episodes, lssser weight gain and can be used in mild renal impairment with caution. He will also be a good candidate to start insulin. When he is being
admitted for heart failure, temporary use of sliding scale is warranted if hes unstable. PROF: AS a rule, pls do NOT use glibenclamide in the elderly. Its long acting and even its metabolites are ACTIVE. Glicazide is excreted by the liver so its relatively safer even in renal impairment. Despite the presence of many unique classes of drugs to treat hyperglycemia in patients with type 2 diabetes, metformin remains the Drug of Choice. Metformin caused less weight gain compared with either the thiazolidinediones or sulfonylureas. Metformin decreased low-‐density lipoprotein levels compared with pioglitazone, sulfonylureas, and DPP-‐4 inhibitors. Patients taking sulfonylureas had a fourfold higher risk of mild or moderate hypoglycemia compared with metformin alone. This is a tremendous advantage of the drug. Most importantly as far as evidenced based medicine is concerned, Metformin is unique in being not only as effective as any other oral antidiabetic therapy in controlling blood glucose, but also having an unparalleled clinical database relating to improved clinical outcomes in pre-‐diabetic subjects, and patients with established type 2 diabetes. 9) on DIABETES! yin ling has asked that I continue with her Viva voce throughout the CNY period. While it is very important that we keep the A1c level as close to normal as we safely can, this MUST vary according to the patient's clinical circumstances, age, risk for hypoglycemia, social background and many other factors. Which patients will you be happy to have A1c levels at 10%, which, for complicated reasons, you can't get them lower or do not want it lower? And who will you want at target of < 7% and even in some < 6.5%? For a patient who is symptomatic and has a blood sugar level of >11.1mmol/l he clearly has diabetes. However can you diagnose with
• Measurement of the hemoglobin A1c level; • Measurement of the fasting glucose level; and what are its limitations? Which is MORE Reliable; MGTT or the hemoglobin A1c level? Please note that blood glucose levels like any laboratory assay can vary even in perfectly normal people. We do one test to see whether a person has diabetes, and then unless the values are clearly abnormal, we need to repeat the same test to verify whether that value is true. Because lab errors can occur, its impt to repeat the same test. The treatment of DM is more than controlling blood sugars, in any real life and exam situation, a global evaluation is essential. Blood pressure: what is the present targets? Every patient who has diabetes and who is older than age 40 years is somebody who will need to be on statin therapy! The occasional man who swears that the statin had caused ED is also a difficult situation as I am not sure its the DM or the drug. What is the role of fenofibrate if any? The role of ACEI and ARBs is another common exam Q. Will you use angiotensin-‐ converting enzyme inhibitors or angiotensin receptor blockers for the prevention of nephropathy in patients who do not have elevated blood pressure levels? How will you advise your patient regarding alcohol intake? YL : we should individualised our HbA1c target according to a patient's age, comorbiditis and general condition. For a young patient say 40-‐50 years old having T2DM, we would like his HbA1c to be tightly control, targeting a 6.5-‐7% to delay the onset of microvascular and macrovascular disease. However if we are looking at an elderly, frail, 70 year old diabetic patient, we would be happy if his HbA1c is around 8-‐10%, tightening the glucose control equals expecting more hypoglycemic events which is detrimental to the old. DM can be diagnosed when a patient has a HbA1c of >6.5%. HbA1c of 6-‐6.5% is considered Pre Diabetes. we can also diagnose DM by fasting blood glucose of >7.0 if there is symptoms. 2 readings is needed if there is no symptoms. IFG is when FBG ranging 5.6-‐7 and IGT when 2 hours post OGTT BG 7.8-‐11.0
Be careful when using HbA1c to diagnose in patients who have high RBC turnover eg thalasemia, any hemiglobinopathies, renal disease and etc. i would like to think that HbA1c is more reliable as it measures glucose control for over a longer period of time.
BP target is at 130/80 for patients with DM, we no longer use the 125/75 target anymore. there is no benefit in lowering BP to such level in this group of patients. Anyone above 40 who has DM deserves a statin. after starting statins and controlling the blood sugar, if TG is still high, fenofibrate is warranted. Fenofibrate can also be used in patients who cannot tolerate statins eg from the myopathy. ACE-‐i and ARB is beneficial for DM patient and we are taught to use them as first line in all DM patient due to the renal protective effect. ACE can help prevent nephropathy and reduce proteinuria. these patients commonly have deranged renal function from diabetes, it is not entirely contraindicated to use ACE/ARB as long as
renal profile are monitored, stop if there is >30% raised of creatinine during a repeat renal profile in more than 2 weeks. we would not use ACE -‐ i once creatinine is >200. We are commonly taught to use ACE-‐i as first line and if patient cannot tolerate ACEI mostly due to an ACE induced cough we would use an ARB instead. Alcohol : cut off units for men is 21 and women 14 per week. but of course taking many units in one setting is bad. encourage moderate alcohol intake. Dear yin ling Hba1c is better than MGGT. A1C captures chronic hyperglycemia better than two assessments of fasting or 2-‐h oral glucose tolerance test of plasma glucose Diabetes has been diagnosed for decades with fasting plasma glucose or, with an oral glucose tolerance test (OGTT). Hyperglycemia as the biochemical hallmark of diabetes is unquestionable. However, fasting and 2-‐h MGTT gauge just a moment of a single day. Many2 factors affect this sample which Hba1c overcomes. BUT Hba1c testing lacks standardization and different labs provide different values for even a same sample. This on top of haemolytic anaemia or lack of EPO or bone marrow problems. So we need to interprete mindful of these. When there is IHD, hypoglycaemia is DANGEROUS. it can ppt arrthymias and even ACS. Hence in proven DM CHD, the target shd NOT be lower than 7%. Serum fructosamine was something I used to test but its unreliable. In thalassaemia trait patients bld sugar profiles remain our bedrock. Same for renal failure patients. Top secrets: Fbs, Hba1c and 2HPP values are all correlated to retinopathy the most specific complication of dm Fbs is poorly correlated to CHD BUT 2hpp and Hba1c is well associated. Bld sugars start dropping in value by 5% every hour after venesection So if the specimen sits on a bench while the technician rests, you are not going to get anything close to reality. Worse in HOT WEATHER. Hba1c is not affected in this way.
Dear YL, ARB vs ACEI In choosing between ACEI and ARB therapy for patients with type 2 diabetes diabetic nephropathy, you have to consider evidence of proven renal protective benefit for ARB treatment versus evidence of a mortality benefit for ACEI treatment shown in patients without established diabetic nephropathy. ARB appears superior to delaying progression to renal failure. But IN NON PROTEINURIC PATIENTS, ACEI has better results with regards to mortality. ACEI in general HPT patients has better outcome for CHD. There is no routine role for combining both You recall OnTarget trial. It was a huge trial testing Telmisartan vs Ramipril and its combination. The angiotensin receptor blocker telmisartan was "noninferior" to the ACE inhibitor ramipril in patients with vascular disease or high-‐risk diabetes in this landmark trial However, the combination of the two drugs was associated with more adverse events without an increase in benefit.
10) on Dyspnoea Dear YL, A 56 years old lady was brought by her daughter to see you. She has many years of breathlessness and wheezing. She used to smoke when she was young. She is now hypertensive and diabetic for 10 years. She has been coughing badly with purulent sputum the last 2 weeks. She wakes up at 5am coughing and breathless. She is on glicazide and metformin. She Is on an ACEI for HPT. SHE USE A LADA PLUS Steroid INHALER And takes theophylline tablets. Her dr gave her a macrolyte antibiotic for ' bronchitis' . What will you do now? Yin Ling: Thanks Prof. This lady is having an exacerbation of her obstructive airway disease evident from the increase breathlessness/purulent sputum and cough. What strikes me first is the macrolide antibiotic being given to her when she's taking theophylline. i wonder which macrolide is it. did she bring it with her? We wouldnt want to give her any erythromycin/clindamycin for the fear of theophylline toxicity which will cause arrhythmia and seizure. Azithromycin is said to interact less with theophylline and we commonly see this combination in GH. Retake a thorough history to diagnose asthma, COPD and rule out sinister problems. ensure no sx showing theophylline toxicity-‐ GI problems, palpitations. assess her recent control of her disease. is the LABA and inhaled steroid enough? Examine her properly. is there any clubbing, cyanosis, her oxygen saturations, the lungs. Any signs of pneumonia on examination, crepitations, wheezing. any signs of heart failure. does she needs to be admitted. A CXR is warranted. CBC and U&E would be helpful. ECG as well. Take off her metformin for the time being and start her on a short acting B2 agonist, a combination of B2 agonist and anticholinergics would be best if i diagnosed her as having COPD. She can take it every 6 hourly for the time being. She is on a LABA and inhaled steroids. i assumed she was being treated as asthma by her doctor, based on her diagnosis and control, this preventer regime can be augmented with a LAAC if her she is having COPD instead of asthma. A small dose of theophylline will be helpful too. A short course of oral steroids will be helpful. About 5 days.
As for antibiotics a respiratory quinolone would be better. Not ciprofloxacin. i would use augmentin but why risk the GI side effects. I will ask her to come back in 3-‐5 days or earlier is she's doing worse. Dear Yin ling, Be sure its not chronic heart failure tipped OVER with a LRTI. She's DM and HPT so risk is high. Pls note she is NOT on a statin, does it matter what her value is? She may not have chest pain bec of DM and yet have critical chd. A baseline ECG is needed and further investigations for CHD may be needed.. Portable O2 sat measurement is available at abt Rm400. It shd be measured if available. Ask her to blow out a match at 1 feet. Old people may NOT have fever so that is NOT A GOOD Indicator of sepsis. ASK FOR PREMORBID STATE FROM THE DAUGHTER! It is often forgotten that smoking induces cytochrome P450 (CYP) 1A2, resulting in altered concentrations and required doses of drugs metabolized by this route. Pls name me some common drugs metabolized by this. Conversely, upon cessation of smoking, concentrations of these drugs can rise to toxic levels unless appropriate dose adjustments are made. Doctors in Internal Medicine need to be aware of this, if potential iatrogenic harm to patients is to be avoided. The Inducers of P450 Carbemazepines Rifampicin Alcohol (chronic) Phenytoin Griseofulvin Phenobarbitone Sulphonylureas
Theophylline is metabolised by cyp 2a1. Smoking induces cyp 2a1 while drugs like cimetidine, ciprofloxacin, erythromycin and clarithromycin inhibits it and cause increase risk of toxicity The cytochrome P450 enzymes are found primarily in the liver, although some (eg, CYP3A4) are also found in substantial amounts in the intestine. They are involved in the metabolism of most medications and are the mechanism by which most pharmacokinetic drug interactions occur. Cytochrome P450 3A4 (CYP3A4) is the superstar; it gets attention because a majority of drugs are metabolized by CYP3A4. 11) on GRAVES IN PREGNANCY Dear yin ling Happy CNY to my 'liver' daughter. A young lady of 25 has Graves Disease. She is newly married and not on contraception. Presently she is on carbimazole 10mg daily and is euthyroid. She has been on treatment for the last 1 year. She has mild proptosis and a moderate size goitre. At follow up you attend to her. What will you do for her? When hyperthyroidism is not controlled in pregnancy, complications include miscarriage, pregnancy-‐induced hypertension, premature birth, low birth weight, intrauterine growth restriction, stillbirth, thyroid storm, and maternal congestive heart failure. Therefore, proper diagnosis and treatment ofGraves' disease and hyperthyroidism during pregnancy is essential. Your answer MUST start with pre pregnancy treatment of women who have Graves' disease, they should conceive only after they are euthyroid. Pls strongly recommend contraception until this is achieved, and recommend that physicians offer counseling to women regarding the implications of treatment on conception plans. TRAb levels tend to rise after Radiodine and remain elevated. For this reason Mx on pregnancy post RAI is more mahfan and in Msia we do not usually use this in young women. Our follow up treatment is not so great and patients often default. If RAI is performed, a pregnancy test should be done 48 hours prior to the RAI administration. When she says NOT PREGNANT, better TEST! For antithyroid drugs, women should be informed about the risks associated with propylthiouracil (PTU) and Carbimazole, and if these drugs are used, PTU should be
used in the first trimester of pregnancy. Carbimazole poses risks to the fetus if used in the first trimester as you noted. Kiv discontinuation of PTU after the first trimester and switching to carbimazole, to decrease the risk of liver disease associated with PTU. Hence, The primary treatment for hyperthyroidism during pregnancy is antithyroid drugs. Because antithyroid drugs cross the placenta, care needs to be taken with the use of antithyroid drugs during pregnancy. In particular, the main concern is the ability of carbimazole to cause congenital malformations -‐ these complications are not associated with the use of PTU. PTU, however, carries a risk of liver toxicity, and hence let PTU be used in the first trimester, and that patients switch to carbimazole in second semester. PTU crosses the placenta and breast milk less. Beta blockers are not typically recommended during pregnancy, as they are associated with intrauterine growth restriction, low fetal heart rate, and hypoglycemia in newborns. All woman taking antithyroid drugs during pregnancy MUST undergo regular monitoring of Free T4 and TSH, so that the Free T4 values remain at, or just above the upper limit of normal, while taking the lowest possible dose of antithyroid drugs. Free T4 and TSH should be measured every two to four weeks at the start of treatment, and every four to six weeks after, to achieve the target blood levels. PLS remember the limitations of TSH tests on pregnancy. Typically, because hyperthyroidism often normalizes during pregnancy bec of higher requirements and volume of dilution, antithyroid drugs can be discontinued in the third trimester in as many as 20% to 30% of patients. For women who have high TSH receptor antibody (TRAb) levels, they may need to continue with antithyroid drug treatment until delivery bec these Abs may cause fetal hyperthyroidism as you pointed out. Thyroidectomy for Graves' Disease During Pregnancy If a woman is allergic to antithyroid drugs, requires high doses to control hyperthyroidism, or is not following her drug therapy, thyroidectomy -‐-‐ is needed, the optimal time is during the second trimester of pregnancy.At the time of surgery, the TRAb levels should be measured to assess the potential risk of
hyperthyroidism in the fetus. There are a number of risks to the fetus including: fetal hyperthyroidism neonatal hyperthyroidism fetal hypothyroidism neonatal hypothyroidism The factors that can affect fetal risk include: poor control of hyperthyroidism throughout pregnancy, which can cause transient central hypothyroidism in the fetus, high doses of antithyroid drugs, which can cause fetal and neonatal hypothyroidism, high levels of serum TRAb which can cause fetal or neonatal hyperthyroidism. Fetal and neonatal hyperthyroidism occurs in between 1% and 5% of all pregnant women with an active or a past history of Graves' hyperthyroidism. In a pregnant woman who has an active or past history of Graves' disease, TRAb should be measured by 20 to 24 weeks of gestation. A value that is more than three times the upper limit of normal is considered a marker of risk to the fetus. Keypoints: Patients who are receiving treatment should receive pre-‐conceptual advice with a view to optimal preparation prior to pregnancy. This includes ensuring they are euthyroid prior to conception and altering medication to PTU which is felt to be superior to carbimazole during pregnancy, especially in the first trimester due to reduced incident of aplasia cutis. Current evidence suggests that following organogenesis, carbimazole or methimazole should be re-‐introduced due to a possible increased risk of hepatitis with PTU. Those on a block and replace regime should also be swapped to PTU alone as thionamides will cross the placenta but levothyroxine will not, thus increasing the risk of foetal goitre and hypothyroidism. Pregnant patients on treatment should have frequent TFT’s throughout pregnancy (monthly) and the dose reduced to the lowest possible to maintain euthyroidism with T4 at the upper limit of the reference range.
Doses are reduced in the latter stages of pregnancy, and not infrequently stopped altogether as the condition undergoes remission. If hyperthyroidism is secondary to Grave’s Disease (or patient has had previous definitive treatment such as surgery or RAI) then TSH receptor antibodies should be measured as high titres can indicate intrauterine or neonatal thyrotoxicosis.
With Dr Donald Alexander, Reader in Medicine, University of Glasgow. This is the Giant who did much research on the radio assays of the Thyroid and who advocated the Block and Replace method of treatment. He took me under his wings as a Post Graduate Fellow in Internal Medicine. 12) on BASICS Dear Yin Chok, & To Ian my nephew reading Medicine in Canberra, If I were teaching you Ian, I would had been VERY Hard on you. I would have ZERO Tolerance for errors and omissions. I would have been doubly demanding of you compared to other students bec you are my nephew. I have been hard on yin ling too for my wife and I treat her like a daughter. As for my other students, Modern propriety demands that I tone down 3 gears.
A generation ago when Msian candidates sat for the MRCP exams in UK, we were not afraid of the clinical cases as we were well exposed to many clinical problems in our daily work. But theoretical questioning can be a problem as we may not be familiar with the FASHION of questions in voque. A good friend was asked. 'What Is the chemical test used to determine the Hb level?' for his viva. Yr1 biochem. Did the test ourselves but Good heavens what's the name of the damn chemical? He failed. I did this experiment in year1 biochem and in yr4 obs posting we the minion med student had to check the patients Hb before they can be discharged. So it's lasered into our brainstems. The patient's blood is mixed with Drabkin's solution, a solution that contains ferricyanide and cyanide. (Risked my life studying medicine!) The ferricyanide oxidizes the iron in the hemoglobin, thereby changing hemoglobin to methemoglobin. Methemoglobin then unites with the cyanide to form cyanmethemoglobin. Cyanmethemoglobin produces a color which is measured in a spectrophotometer. The color relates to the concentration of hemoglobin in the blood which we obtain by comparing with a standard chart. Today I am going to ask you a series of basic questions. 1. Your patient has ESR 115. What are your thoughts? YL: There's only a few causes for three digits esr. Multiple myeloma, GCA(temporal arteritis), advanced malignancy, TB and SLE (connective tissue disease) and also in severe sepsis. Prof : And we must not FORGET causes of a LOW ESR too! Lower-‐than-‐normal levels can occur with: Congestive heart failure Hyperviscosity Hypofibrinogenemia Low plasma protein (due to liver or kidney disease) Polycythemia Sickle cell anemia
The rate of fall of red cells in anti-‐coagulated plasma is influenced by a number of factors. Sedimentation is influenced greatly by the extent to which the red cells form rouleaux or large clumps of cells. This rouleaux formation is related to the plasma proteins which overcome the negative surface charge on red cells. The haematocrit also influences the ESR. Anaemia accelerates sedimentation and polycythaemia retards it. Are you all aware that Aging alone elevates it? Perhaps some low grade inflammation kills us all eventually. Upper limit of Normal for males is Age divide by 2 and for Females is Age PLUS 10 divide by 2! Are you aware that merely being Diabetic also increases it? Maybe the same reasons cause that. With increasing age after 50 years, the ESR rises and, in the elderly, many apparently normal subjects have increased readings. But it is NOT 3 figure values. Physiological increases in the ESR occur in pregnancy and the puerperium. The ESR is a measure of the presence and severity of inflammatory, auto immune and other morbid processes. NOTE THAT a normal ESR cannot be taken to exclude disease Most acute or chronic infections, neoplastic diseases, collagen diseases, renal or other diseases associated with changes in plasma proteins lead to acceleration of sedimentation. It is also useful in monitoring disease activity in certain disorders. It has been used for this purpose in tuberculosis, rheumatic fever, rheumatoid arthritis, Hodgkin's disease and non-‐Hodgkin's lymphomas, myeloma and macroglobulinaemia. The investigation of a very high ESR involves full clinical assessment of the patient which will usually reveal the cause. There are a number of well known associations with a high ESR which include what had been stated and the following: Recent respiratory tract infection and anaemia due to mycoplasma infection Cardiac bacterial endocarditis is impt as it may be low grade and missed. Be careful in drug addicts. Multiple myeloma is THE CLASSIC cause never to be missed when grilled. Or come back next year.
2. The LFT came back. As HO you review the results. AST more than ALT by 3 times. Thoughts and why? ALT more than AST 2 times. Thoughts and why? AST equal to ALT. Thoughts? YL: AST is mainly in the mitochondria while ALT is cytosolic. Inflammation to hepatocytes that break down cell membrane will release much more ALT compare to AST. Eg hepatitis, drug induced inflammation. Cirrhosis will cause hepatocytes death which release more AST likewise with MI. AST 2 times more than ALT is specific for alcoholic liver disease as alcohol induces AST. AST and ALT equivalent can mean liver cell death or can be seen in v chronic liver disease when there is not much increase in both transaminases. 3. Your patients Urea is elevated but Creatinine is normal. Thoughts and why? ? 4. Se calcium is tested below normal. Patient Is well with normal ECG. What are your thoughts? 5. Se Alk phos high and se calcium high 6. Se Alk phos normal and Se calcium high 7. Se calcium normal and se Alk phos high Dear yin ling, there are some unique aspects of elevated ALKALINE PHOSPHATASE Body sources of alkaline phosphatase include neo-‐osteogenesis of bone, (NEW BONE FORMATION IS NEEDED) intestines, liver, placenta, and white blood cells. Often elevated levels are associated with complications of the liver or gallbladder. Gamma glutamyl transferase (GGT) will determine hepatic versus other origins of alkaline phosphatase elevation.
In the presence of liver disease, increased levels of Gamma glutamyl transferase is seen but in persons who have recently ingested even minute amounts of alcohol it is elevated and is therefore a less specific test. Isoenzyme testing is also an option to determine the source of alkaline phosphatase elevation. An elevation of hepatic alkaline phosphatase usually implies biliary tract pathology with resultant cholestasis, but this elevation also occurs with infiltrative diseases of the liver, masses or abscesses of the liver,primary biliary cirrhosis and primary sclerosing cholangitis. Where alkaline phosphatase elevation is secondary to bone disease, its elevation is a marker of osteoblastic activity. In bony disease, the alkaline phosphatase elevation is usually associated with hypercalcemia. Common bone diseases include metastatic bony lesions, Pagets disease, secondary hyperparathyroidism of renal disease, osteomalacia, rickets, primary hyperparathyroidism, and even hyperthyroidism. I had patients with Graves who presented with high Alk phos which normalised on treatment. BUT the exception is multiple myeloma where hypercalcemia is secondary to osteoclastic bone disease and the alkaline phosphatase level is normal. I found this fascinating as a student. Clinically, pathologic fractures of the sternum are considered pathognomonic of multiple myeloma, and bone pain of the ribs or back that is exacerbated by movement is considered characteristic. Add raised se calcium, high esr, normal alk phos and raised globulins and I will knock your head if you cannot diagnose. During pregnancy, maternal alkaline phosphatase increases. This is the result of placental alkaline phosphatase production, and the elevation resolves puerperium. Dear Yin ling, I had only seen 1 patient with very high Direct Bilirubin and Normal Alk phos. This is in a patient with a leaking T tube. Direct conjugated bilirubin leaked into the peritoneum and was absorbed back into the circulation
8. Patient is clinically suspected to have malaria. Consultant asked for BFMP X 3 The HO dutifully on 3 days took 3 samples and all 3 were negative. What could be wrong? Dear Yin ling, Taking blood films for malaria parasites shd be done when parasitaemia is highest. This is when fever Is rising. So it is not the HO merely taking blood from a vein when it is convenient to him. Up to 3 specimens can be taken in the same day if fever is noted to be rising. Hence for simplicity this is done via a finger prick. A thick film for screening and a thin film for identification is made each time. HOs must know these techniques as malaria screening is common in Msia. Pls make sure that the alcohol used to clean the finger has DRIED before you prick the finger at the side of the distal phalanx. To ensure that the thick film is not too thick pls apply the blood to the slide from BELOW ie the underside of the glass slide. You can control it easier this way instead of dropping the blood.
The usual horror story when BFMP X 3 is ordered is that the HO takes a syringe and draws a venous specimen at end of ward rounds and proceed to make 3 sets of slides.
9. Patient had features of filiariasis. Consultant asked for blood films for the parasite. The HO took 3 specimens on his shifts. What is wrong? Dear Yin ling, What is the brand of the watch you wear on your wrist? Because I will like to know how the filiaria worm tells time! Bancroftian and brugian filariasis tend to show nocturnal periodicity, so it is recommended that samples be collected between 10:00 pm and 2:00 am. Yup its a midnight show. So the dear HO who pokes a vein after rounds Is not going to find anything. Its also a fingerprick capillary specimen and similar Thick and thin films but done literally by a Vampire HO at the stroke of midnight.
13) on FEVER Dear YL, What is fever? What is the mechanism behind fever? Why can some people with no obvious illness have fever? Why do some people with illness have NO fever? I want to EMPHASIZE strongly that the elderly may not have the ability to develop Fever when ill. Absence of fever does not mean anything Chee Yong Chuan: Fever is defined as the elevation of core body temperature above normal. In normal adults, the average oral temperature is 37 degrees Celsius. The febrile response is a complex physiologic reaction to disease involving a cytokine-‐mediated rise in body temperature and generation of various acute phase reactants. Fever is thus considered a hallmark of IMMUNE SYSTEM ACTIVATION, resulting in a regulated rise in body temperature. So what happens is that exogenous pyrogens from infectious agents, toxins, tumours induce production of pro-‐inflammatory cytokines, such as interleukins, TNF which subsequently enter the hypothalamic circulation and stimulate release of local prostaglandins(this is where our antipyretics and NSAID exert their effects). The body will then react to rise the temperature to this new thermal set point(manifested by chills and shivering). Why do some people with illness have no fever? I can observe that response to fever varies with age. Elderly patients especially are unable to regulate their body temperature to the same degree as young adults. Prof Wong had reiterated many times that older patients with serious infections have substantial prevalence of a pyrexia or LOWER febrile responses! Don't be surprised to see hypothermia instead in full blown sepsis in this group of patients. Fever is also considered to be an important host defence mechanism, hence in those who are immunocompromised i.e HIV, patients receiving steroid therapy, neutropenic patients, due to the inability to mount an adequate immune response, might not give you the textbook febrile response that you would have expected. I can think of a few examples where patients who are well but developing fever. 1) Transfusion associated fever. Again, due to activation of the immune system against antigen on the donor blood 2) Drug induced, probably affects the ability of the body to dissipate heat, or
through immune system activation, serum sickness, allergy 3) Factitious fever Prof : difference between fever and hyperthermia
Prof : Dear Yin Ling, I hate all these definitions as my RAM is simply too small to process them. I think of FEVER as a problem but you are sitting for exams and hence stuck in the system. DEFINITIONS FUO—>38.3C [>101.8F], duration >3 weeks, diagnosis uncertain after 3 days in hospital or "three outpatient visits"!! This is close to our old definition. NOSOCOMIAL FUO—hospitalized patients, >38.3C [>101.8F], diagnosis uncertain after 3 days and infection not present or incubating on admission IMMUNE-‐DEFICIENT (NEUTROPENIC) FUO— >38.3C [>101.8F], >3 days, neutrophil count 38.3C [>101.8F], duration >3 weeks for outpatients or ">3 days for inpatients"
The era of high technology has changed the goalposts considerably, note inpatients now are THREE days to a diagnosis. With every scan thrown in from PET CT to MRI, 3 days in the IDEAL hospital appears enough. FEVER, NYD—persistent fever that has not yet met the definition for FUO. In the HISTORY -‐the pattern and duration of fever, -‐the associated symptoms (cough, dyspnea, hemoptysis, chest pain, diarrhea, abdominal pain, dysuria, urethral discharge, hematuria, neck stiffness, headache), -‐any rash (palpable purpura, exanthem), -‐any exposure (food, water, plants, animals, insects, infected human secretions), -‐weight loss, night sweats, -‐travel history, sexual history, HIV risk factors, immunizations, -‐past medical history (rheumatologic disorders, malignancy, alcohol), -‐medications are ALL CRUCIAL. PHYSICAL exam— vitals (tachycardia, tachypnea, hypotension, fever, hypoxemia), oral ulcers, lymphadenopathy, nuchal rigidity, respiratory and cardiac examination (murmurs), temporal artery, abdominal examination (hepatosplenomegaly), prostate examination, skin lesions (morphology, distribution), insect bite marks, joint examination Always think of: INFECTIONS—TB (pulmonary, extrapulmonary, miliary), abscess (liver, splenic, perinephric, psoas, diverticular, pelvis), osteomyelitis, endocarditis NEOPLASTIC—hematologic (lymphoma, leukemia, multiple myeloma, myelodysplastic syndrome), solid tumors (renal cell, hepatoma)
COLLAGEN-‐VASCULAR—vasculitis (giant cell arteritis, Still’s disease, polyarteritis nodosa, Takayasu’s arteritis, Wegener’s granulomatosis, mixed cryoglobulinemia), lupus, rheumatoid arthritis DRUGS—antimicrobials (sulfonamides, penicillins, nitrofurantoin, antimalarials), antihistamines, antiepileptics (barbiturate, phenytoin), NSAIDs/ ASA, antihypertensives (hydralazine, methyldopa), antiarrhythmics (quinidine, procainamide), antithyroid, iodides, quinine, illicit (cocaine) UNCOMMON CAUSES OF FUO— endocrine (hypothalamic dysfunction, hyperthyroidism, pheochromocytoma, adrenal insufficiency), infections (dental abscess, leptospirosis, psittacosis, melioidosis, syphilis, gonococcemia, hereditary periodic fever syndromes (familial Mediterranean fever, alcoholic hepatitis, hematoma, factitious fever Pls do not forget the good old CLASSIC DEFINITION (1961)—>38.3C [>101.8F], duration >3 weeks, diagnosis uncertain after 7 days of investigation in hospital Prof : Malignancies have now superseded infections as the most common cause of fever of unknown origin (FUO). Did you know this? In the past infectious diseases were the most common etiology of FUO, and neoplasms constituted the second most frequent category. This shift from infectious to malignant etiology as the most frequent cause of FUO is related to several factors. Firstly, due to the widespread introduction of computed tomography (CT) and magnetic resonance imaging (MRI), many intra-‐abdominal causes of infection are diagnosed early and therefore do not meet the definition of FUO. Sub phrenic abscesses, pelvic pathologies and even sinus infections well hidden from the clinician Is not exposed clearly. Secondly, radionucleotide imaging studies, that is, indium scans, gallium scans, and bone scans, have been useful in identifying occult malignancies undetectable by other means. Now PET CT has made detection of both well hidden infections and malignancies much easier.
Prof : lymphoma is the most common etiology of neoplastic fever of underdetermined origin. The pathophysiology of tumor-‐induced fever may be due to several mechanisms of which release of cytokines from tumor cells or tumor necrosis factor and interleukin-‐1; necrosis of tumoral tissue; all contribute. I cannot resist asking you, What is the Naproxen challenge in FUO? ? THE NSAID naproxen Is very effective in suppressing tumor fever and this property may be useful in elucidating suspicion of cancer in patients with prolonged, undiagnosed fever. Naproxen IS THE classically touted agent for suppressing tumor fever due to its unique ability to suppress tumoral cytokines in preference over infectious cytokines. While the “naproxen challenge” may be useful in evaluating prolonged fever suspected to be of neoplastic origin, it must be utilized in the context of a thorough, clinically-‐driven assessment. 14) NMS A 66-‐year-‐old male was hospitalized for increasingly aggressive behavior. He had no prior psychiatric admissions. On the day of admission after he sustained a fall, a CT scan of the brain revealed a subarachnoid hemorrhage at the right superior sulcus and a possible hemorrhagic contusion at the left frontal lobe. Over the course of hospitalization, the patient had a series of CT scans showing resolution of the hemorrhage. He was started on olanzapine for intermittent agitation. Olanzapine was titrated to 7.5 mg daily.Ten days later the patient became abruptly somnolent with body temperature reaching 39.7 º C and severe muscle rigidity in both upper and lower extremities. He had severe diaphoresis and fluctuation of blood pressure and pulse. Laboratory data revealed elevation of white blood cells to 14800 K/L, creatine phosphokinase to 2800 U/L (normal < 174 U/L), and mild elevation of serum alanine and aspartate aminotransferase. MRI of the brain, CSF studies, and chest radiograph were unremarkable.
What is the diagnosis? What will you do now? Pathophysiology fr Medscape '' The most widely accepted mechanism by which antipsychotics cause neuroleptic malignant syndrome is that of dopamine D2 receptor antagonism. In this widely accepted model, central D2 receptor blockade in the hypothalamus, nigrostriatal pathways, and spinal cord leads to increased muscle rigidity and tremor via extrapyramidal pathways. Hypothalamic D2 receptor blockade results in an elevated temperature set point and impairment of heat-‐dissipating mechanisms. Peripherally, antipsychotics lead to increased calcium release from the sarcoplasmic reticulum, resulting in increased contractility, which can contribute to hyperthermia, rigidity, and muscle cell breakdown. Beyond these direct effects, D2 receptor blockade might cause neuroleptic malignant syndrome by removing tonic inhibition from the sympathetic nervous system. The resulting sympathoadrenal hyperactivity and dysregulation leads to autonomic dysfunction. This model suggests that patients with baseline high levels of sympathoadrenal activity might be at increased risk. While this has not been proven in controlled studies, several such states have been proposed as risk factors for neuroleptic malignant syndrome.'' Diagnostic features of NMS: Neuroleptics within 1 to 4 weeks. Hyperthermia (above 38°). Muscle rigidity lead pipe. Five of the following: Changed mental status.Tachycardia.Hypotension or hypertension.Tremor.Incontinence.Diaphoresis (excessive sweating) or sialorrhoea. Increased creatine phosphokinase (CPK) or urinary myoglobin. Metabolic acidosis.Leukocytosis. Exclusion of other illnesses (neuropsychiatric, drug-‐induced, systemic).
Prof : Have you heard of 'an extreme Parkinson's crisis' ? It may be possible that NMS is as an extreme parkinsonian crisis resulting from overwhelming blockade of dopamine pathways in the brain. In this view, NMS resembles the parkinsonian-‐hyperthermia syndrome that can occur in Parkinson’s disease patients following abrupt discontinuation or loss of efficacy of dopaminergic therapy, which can be treated by reinstituting dopaminergic agents. Evidence to support this view includes: • Parkinsonian signs are a cardinal feature of NMS .• Withdrawal of dopamine agonists precipitates the syndrome. • All triggering drugs are dopamine receptor antagonists. • Risk of NMS correlates with drugs’ dopamine receptor affinity. • Dopaminergic agonists may be an effective treatment. • Lesions in dopaminergic pathways produce a similar syndrome. • Patients with NMS have demonstrated low cerebrospinal fluid concentrations of the dopamine metabolite homovanillic acid. Yin ling: this patient is likely having what we know as a Neuroleptic Malignant Syndrome due to the Olanzapine that was just started ten days ago. Neuroleptic malignant sydrome is caused by drugs causing Dopamine receptor antagonists (commonly antipsychotics) and also withdrawal of Dopamine agonists (commonly anti Parkinsonian drugs). temperature regulation became haywire and patient presents with classic tetrad of hyperthermia which is unable to be brought down by antipyrogens, RIGIDITY, mental confusion/somnolence/coma, and autonomic dysfunction (perfused sweating, tachycardia, labile BP and etc). it can occur after a few days of taking the drugs up to years after that. classically it occurs within a few weeks.
Labs wise: increase total white and v high CK, deranged transaminases and decrease in se iron is classical for NMS. Stopping the culprit drug is first and foremost. Secondly bring down the patients temperature with methods like cooling blanket, hydration, and medical therapy with dopamine agonists like bromocriptine can help. Dantrolene a muscle relaxant is used too but not available in many hospitals. Supporting patient's ABC is of course vital NMS has been claimed to have some similar genetic profile as Malignant Hyperthermia that occurs when anaest drugs classically succinylcholine is administered. MH is autosomal dominant and a drug history will help us with diagnosis. It is often difficult to differentiate Serotonin syndrome and NMS. even more so when serotonin containing drugs will also have dopamine antagonist effect. Serotonin syndrome is due to a high level of serotonin in the body caused by giving two serotonin containing drugs concurrently, giving these drugs tgt with CYP 2D6/ 3A4 inhibitors OR giving a Long Acting drugs which increase serotonin eg Prozac(fluoxetine). classical drugs that causes SS are antidepressants like SSRI, SNRI, MAOi-‐A (MAOi-‐B that we are giving to our parkinsons disease patients won't cause that effect. i don't know why). other common drugs are PAIN CONTROL drugs eg Tramadol, fentanyl, meperidine; ANTIEMETRICS eg Maxolon, granisetron(Kytril), ondansetron; TRIPTANS, LITHIUM. Pathophysiology of NMS and SS is different because SS does not cause hyperthermia by altering the hypothalamus setpoint. it is due to the overall hyperexcitability. The few ways to differentiate: 1) Serotonin syndrome causes neuromuscular excitation : hyperreflexia, myclonus, clonus, increase in bowel sounds, pupils dilatation, as opposed to LEAD PIPE RIGIDITY in NMS. 2) Lab reuslts of increase total white and CK and transminases and decrease se iron will point to NMS. SS less likely 3) SS can occur immediately after serotonin containing drugs is given while NMS
might occur after a few weeks. Mx of SS : diazepam for the hyperexcitability, intubation and sedation may be needed. anti serotonergic drug like cyproheptadine can be given. Dr Hu : Neuroleptic malignant–like syndrome (NMLS) …… Withdrawal or dose reduction of levodopa in patients with Parkinson’s disease (PD) has been reported to precipitate a potentially fatal syndrome closely resembling neuroleptic malignant syndrome (NMS). This syndrome is referred to as neuroleptic malignant–like syndrome (NMLS) and parkinsonism-‐hyperpyrexia syndrome by some authors. Clinical features of NMS and NMLS are very similar and include high fever, marked rigidity, altered consciousness, leukocytosis, autonomic dysfunction, rhabdomyolysis with elevated serum creatine kinase (CK) levels, and renal failure. NMS and NMLS share a similar pathophysiologic mechanism consisting of an acute reduction in nigrostriatal and hypothalamic cerebral dopaminergic transmission. In the case of NMS, the primary mechanism occurs when neuroleptics block D2 dopamine receptors, while the cause of NMLS is the withdrawal of exogenous dopamine. This usually occurs in the form of its precursor, levodopa. Clinical conditions that may contribute to the occurrence of NMLS include disturbance in the gastrointestinal tract resulting in poor absorption of levodopa, intercurrent infection, dehydration due to heat, and poor adherence to medications. It is well recognized that “high dietary protein” intake can impair the absorption of levodopa, leading to loss of efficacy and PD symptom fluctuations. The amino acids of the protein may compete with levodopa for absorption in the gut and for transport through the blood-‐brain barrier. (Health-‐care professionals should be aware of the interaction between levodopa and protein content of enteral nutrition to avoid the occurrence of NMLS in patients with PD.) The treatment of NMLS due to levodopa withdrawal consists of supportive measures, hydration, and Levodopa reintroduction or increase in dose can be effective. (The Annals of Pharmacotherapy 2010 September, Volume 44)
15) on Cardiac Tamponade Yin Ling, A Patient was stabbed in 4th intercostal space, left to sternal border, he appears anxious, has marked difficulty breathing, with pain radiating down left arm, and the veins in his neck distend upon inspiration. What is the DIAGNOSIS? YL: Kussmaul's sign for Cardiac Tamponade Prof : Yes it is a Cardiac TAMPONADE -‐this Results from accumulation of fluid/blood in the pericardial cavity-‐this compresses the heart chambers Because of poor venous return the Neck vein has distension= Resulting in Kussmaul's sign. -‐ DECREASED venous return and REDUCED cardiac output
16) on THE ELDERLY Dear Yin ling, Elderly patients often come to the Physician with abd pain. Are you aware that the Classical history and signs are often not seen in the elderly? Multiple factors contribute to the diagnostic difficulty and high incidence of complications seen in elderly patients.
Immune function tends to decrease with advancing age. Many elderly patients have underlying conditions such as diabetes or malignancy, further suppressing immunity. To make it worse Elderly patients often have underlying cardiovascular and pulmonary disease, which decreases physiologic reserve and predisposes them to conditions such as abdominal aortic aneurysm (AAA) and mesenteric ischemia. The exam patient typically has multiple morbidities cutting across many disciplines. Elderly patients also have a high incidence of asymptomatic underlying pathology. Up to one half of elderly patients have underlying cholelithiasis something i see so often, one half have diverticula, and 5-‐10% have AAA. Remember you see me screening for this in all over 50 Understanding that elderly patients may present very differently than their younger counterparts also is important. Elderly patients tend to wait much longer to seek medical attention than younger patients as they are very money conscious, and they are much more likely to present with vague symptoms and have nonspecific findings on examination. Many elderly patients have a diminished sensorium, allowing pathology to advance to a dangerous point prior to symptom development. Painless infarcts for eg is common. Elderly patients with acute peritonitis are much less likely to have the classic findings of rebound tenderness and local rigidity. If they come to see me THEY ARE SICK. They are less likely to have fever, leukocytosis, or elevated C-‐reactive protein level. In addition, their pain is likely to be much less severe than expected for a particular disease. Because of these factors, many elderly patients with serious pathology initially are misdiagnosed with benign conditions such as gastroenteritis or constipation. Have a high degree of suspision and a low treshold for Ix when managing them
17) on BP AND MAP Dear Yin Ling Chok over dinner just now you sat in between as the Consultant Anaesthetist and I chatted. The discussion was whether MAP is better or equivalent to Systolic diastolic pressure in monitoring patients? You did not say anything but what would you had said if this was asked of you in your exam? You will have recalled that I contributed my understanding of its physiology. Always the basic sciences. MAP is considered to be the perfusion pressure of the organs in the body. Hence I asked her in what context she was refering to and when she replied in septicaemia; it is then obvious that MAP would be excellent as we are worried about multi organ failure in septicaemia. Typically when the MAP is greater than 60 mmHg, that is enough to sustain the organs of the patient. That is why the Consultant referred to that figure and used 65 as her example. The MAP is normally between 70 to 110 mmHg If the MAP falls below this for an appreciable time, the organs will not get enough Oxygen perfusion, and will become ischemic. The MAP is the average over a cardiac cycle and gives us a slightly better idea of perfusion when compared to looking at the systolic diastolic pressures alone. Because diastolic pressure is important you will note that in our typical calculation, the diastolic is multiplied by 2. I also explained that in the non ICU setting, we look at systolic diastolic pressures instead because the circumstances are different. In the clinic following up HPT patients for example, we are concerned about CVS outcomes. We know that the SBP or PP predicts CVD among older men. As I shared in my talk, the stolic BP and its variability is very important. But as for MAP, we are unsure of its correlation with outcomes unlike SBP and DBP which is highly correlated and better predicts CVD. MAP is an alternative and preferable measurement to systolic blood pressure in monitoring patients at risk for hypotension and the detection of organ hypoperfusion. This is a fundamental clinical use which differs. In sepsis for eg,
tissue hypoperfusion is the pathophysiologic endpoint of low blood pressure, and MAP, rather than SBP, is the physiologic driving force behind blood flow to organs and tissues. This discussion over dinner could well be critical to your understanding and hence I wrote to ensure that you do understand. As BP progressively drops, a SBP of 80 mmHg or less becomes less sensitive and physiologically less appropriate measurement of hypotension than MAP. The MAP provides an objective assessment of hypotension that may precede hemodynamic decompensation.
18) on BP Variability 1) In the clinic setting we are just taking a snapshot of the patients overall BP in 24 hours. How accurately does this reflect the 24hours BP? We are moving towards home BP monitoring and ambulatory BP monitoring – esp to detect masked hypertension and white coat hypertension 2) Masked hypertension : group of patients with normal BP in clinic but in their daily lives their BP are in the high side. – easily missed group of patients hence high CVS risk! 3) Normal healthy person has a dip of their BP when they are sleeping at night. When we lose this dipping phenomena (patient who are diabetic, renal failure, autonomic neuropathy, taking cyclosporin etc) OR WORSE, have an early morning BP surge, have higher CVS risk! 4) Rothwell wanted to answer a question : whether high BP or BP variability poses the risk for stroke. Results : BPV. 5) Hence we need a drug that can control BP for over 24 hours. – a long acting antihypertensive. 6) ASCOT trial compared a beta blocker (atenolol) and a CCB, in which CCB shows greater benefit in lowering stroke. Of course, amlodipine was a long acting drug compared to atenolol 7) JNC8 guidelines : for all patients we aim for BP target of 60 years
old, threshold is higher at 150/90mmHg. 8) Older ppl will often has a higher systolic BP and lower diastolic BP. 9) Older teaching : in CKD patients keeping BP 100 mL; e.g., CT of the abdomen or pelvis, CT angiography of the aorta or lower extremities) should restart metformin no earlier than 48 hours after the procedure.3 For small volumes of contrast, patients with normal renal function taking metformin may not require any changes in care If patients with normal renal function who are taking metformin receive less than 100 mL of intravenous contrast (e.g., enhanced CT of the brain), stopping metformin and/or rechecking creatinine levels 48 hours after the procedure may be unnecessary, because the risk of contrast-‐induced nephropathy in patients with normal renal function is very low.5 Prof : Why are these risks different for males and females? Different body tissues have different sensitivity to radiation. Skin and bone are not very sensitive, but breast tissue, bone marrow, and the lining of the stomach and intestine are sensitive to the effects of ionising radiation. On average, females are more sensitive to the effects of ionising radiation than males.
Why are these risks different for children? The principal risk for children exposed to X-‐rays is that at the time of exposure, their growth means more cells are dividing, providing a greater risk of radiation disrupting cell development. Children also have a longer life expectancy, giving a longer time for the effects of any radiation damage, if present, to have an effect on long-‐term health. 28) On TB Dear Yin ling, M. tuberculosis divides every 15–20 hours, which is extremely slow compared to other bacteria, which tend to have division times measured in minutes (Escherichia coli can divide roughly every 20 minutes). It is a small bacillus that can withstand weak disinfectants and can survive in a dry state for weeks. Its unusual cell wall, rich in lipids (e.g., mycolic acid), is likely responsible for this resistance and is a key virulence factor. When in the lungs, M. tuberculosis is taken up by alveolar macrophages, but they are unable to digest the bacterium. Its cell wall prevents the fusion of the phagosome with a lysosome. Smart right! That's why giant cells and granulomas form to contain it. AFB direct smears and culturing method is the standard way of screening TB. Direct smears often fail when the bacterial load is low while culture will pick it up as it allows the bacteria to multiply for identification. Most common media(egg-‐based) used in Malaysia is the Lowenstein-‐Jensen media (used before) and now the OGAWA (replacing LJ media) M. tuberculosis is grown on a selective medium known as Lowenstein-‐Jensen medium, which has traditionally been used for this purpose. However, this method is quite slow, as this organism requires 6–8 weeks to grow, which delays reporting of results. Löwenstein-‐Jensen (LJ) medium is most widely used for tuberculosis culture. LJ medium containing glycerol favours the growth of M. tuberculosis. A faster result can now be obtained using Middlebrook medium or BACTEC. BUT What is BACTEC?
It is a broth-‐based culture system designed to improve the speed and sensitivity of detection. The BACTEC system is based upon Middlebrook 7H12 medium containing 14C labelled palmitic acid with a mixture of antibiotics (PANTA) to suppress other bacterial growth. The addition of NAP (p-‐nitro-‐alpha-‐acetylamino-‐beta-‐ hydroxypropiophenone) in the medium suppresses growth of other M. tuberculosis complex organisms such as M. bovis but does not differentiate other nontuberculous mycobacteria from M. tuberculosis. Bacterial growth is indicated by the detection of 14C released by M. tuberculosis as it metabolizes the palmitic acid. In AFB smear-‐positive specimens, the BACTEC system can detect M. tuberculosis in approximately eight days compared to approximately 14 days for smear-‐negative, culture-‐positive specimens. However, the high cost of the equipment and the need for radioactive material that requires disposal exclude its use in most TB endemic communities. Growth detected by the indicator system in drug-‐containing broth is interpreted as resistance to the drug. The turnaround time for resistance testing is 10 days. This method is very successful and reliable and that confirmatory results for M. tuberculosis can be obtained within two weeks. However, the BACTEC machine is very expensive to purchase and to operate. What is OGAWA MEDIUM? It is an egg based medium to culture M. tuberculosis. OGAWA MEDIUM is cheaper than Löwenstein-‐Jensen because it is made without asparagine. LJ need a lot of ingredients compared to Ogawa. This is why LJ media costs more. This method is much cheaper than Bactec. The ideal medium for isolation of tubercle bacilli should (a) be economical and simple to prepare from readily available ingredients, (b) inhibit the growth of contaminants, (c) support luxuriant growth of small numbers of bacilli and (d) permit preliminary differentiation of isolates on the basis of colony morphology. The Ogawa media is better than LJ in terms of cost, growth rate and contamination rate. BUT Speed is King with A premium to pay The mean detection time for M. tuberculosis complex was 15 days with the BACTEC method, and 26 days with the Ogawa method.
29) ON STROKE Dear Yin ling, Why is it that we refer to 7th and 12th CNs as either UMN or LMN but not when we speak of the other CNs? Almost all of the cranial nerves receive bilateral innervation from the fibers of the pyramidal tract. This means that both the left and right members of a pair of cranial nerves are innervated by the motor strip areas of both the left and right hemispheres. This redundancy is a safety mechanism. If there is a unilateral lesion on the pyramidal tract, both sides of body areas connected to cranial nerves will continue to receive motor messages from the cortex. The message for movement may not be quite as strong as it was previously but paralysis will not occur. The two exceptions to this pattern are the portion of 12th CN that provides innervation for tongue protrusion and the part of 7th CN that innervates the muscles of the lower face. These only receive contralateral innervation from the pyramidal tract. This means that they get information only from fibers on the opposite side of the brain. Therefore, a unilateral upper motor neuron lesion could cause a unilateral facial droop or problems with tongue protrusion on the opposite side of the body. For example, a lesion on the left pyramidal tract fibers may cause the right side of the lower face to droop (R UMN 7th CN palsy) and lead to difficulty in protruding the right side of the tongue (R UMN 12th CN palsy).
But even the 12th often has a small supply from the other side, hence the quick recovery of the deviation in UMN lesions. While most people have bilateral innervation of the 12th CN, this is NOT seen in others. Whats the bottom line then... contralateral innervation is dominant while there is bilateral innervation in some. Hence in a UMN lesion, the tongue deviation is seen early and then may improve with time, in those with very significant bilateral innervation, in a UMN lesion the deviation is minimal or not seen at all. The other cranial nerves involved in speech and swallowing would continue to function almost normally as both members of each pair of nuclei still receives messages from the motor strip. Because most cranial nerves receive bilateral innervation, lesions of the upper motor neurons of the pyramidal tract must be bilateral in order to cause a serious speech problem. Hence Pseudo Bulbar and Bulbar palsies. On the other hand, unilateral lesions of the lower motor neurons may cause paralysis. This occurs because the lower motor neurons are the final common pathway for neural messages traveling to the muscles of the body. At the level of the lower motor neurons, there is no alternative route which will allow messages from the brain to reach the periphery. Muscles on the same side of the body as the lesion will be affected. When there is eg a 3rd CN palsy it is understood to be a LMN lesion.
You have reached the MIDPOINT of this book. Why I am CRANKY when Teaching my medical students! I believe that this is because my body and mind is irreversibly damaged/distorted by years of medical school training. I believe that the Brain surgery that was done on my brain made it non compliant to any students not conforming to the uni culture of last century. Let me recall some highlights... In year1, we had a Professor of Anatomy who was so fierce that grown men will cry when she walked in. The 'name who must not be mentioned' will walk around with a forcep in the dissection hall, randomly pick up a structure and BOOM "Why is this? Origin? Insertion? Function??" Most of us were mentally castrated by the time we finished anatomy and any survivors would have been poisoned by the all overwhelming Formalin anyway! By the way, we dissected with our BARE HANDS! That's the 20th century for you. Thank goodness Dr Tan Too Moh my year one buddy was a surgical genius who faithfully dissected every superficial nerve and tendon while I navigated from the dissection manual. When Prof "Who must not be named" walked near, I leap into life and buried my hands in the leathery body. We had Prof Raman in Physiology who recurrently threatened to hang us on the tree whenever we flunked his MCQs. Many of us would have died many times! But this was one great teacher who taught us much3 Physiology. The Prof Raman physiology quiz now held annually is in his memory. And Prof Loke of Biochemistry made us feel so so small when he wrote on the Blackboard with BOTH HANDS simultaneously and effortlessly the complicated formulas of Biochemistry like you and I writing a nursery rhyme. OK we felt like Cretins by 1st year! And I hated the DNA structures that they taught.... why oh why did they torture us with that! And each subject had its own Essay question examination, MCQ and practical exam!!! 9 exam sessions!! By some unknown miracle we survived year1 only to plunge into the arms of Prof Chai in year2, his Microbiology in no way made his hands micro.. for he will without hesitation pinch anyone of us squarely in the belly when we do not know the Stains, Cultures and immunology of all his unseen friends. OUCH3! BTW this was before the
days of measurement of abdominal skin fold thickness, had the good Professor known then, he would have collected enough data for his PhD. Prof Prathap of Pathology was the gentleman of gentlemen, ever so calm, cool and collected. OK he was probably the only man in medical school who did not scold us, BLESS the man. In Parasitology, we stirred shit in saturated saline like how your mummy would beat flour to make a cake, the difference being that the cake will smell delicious while we smell in a manner that gave reason for the medical faculty to be placed in the far flung corner of the campus. It also explains why the beautiful girls from the Arts faculty stayed put in their diagonally placed faculty. Some of those parasites may well have entered our brains too for we also slept, studied and ate in the very same 'multi-‐discipline' laboratories'. Pharmacology was about Pharmacokinetics and Phamacodynamics; it made our minds as contorted as the double helix. The poor cats from the Clinical Hostel involuntarily gave their lives for us to understand "Therapeutic Index" and "Lethal doses"! Aiyo, I still shudder when I think of the poor feline on that heated table hooked up on monitors. We watched in horror as adrenaline was slowly infused into its veins and the cardiac monitor went dit, dit, dit then a hundred times faster when a technician whipped out a scalpel and opened up its chest in like 3 secs exposing a fibrillating cat heart. OK another Psychological scar lasered into my brain! Whoopie! We finished the Basic sciences and walked proudly into University Hospital with our Brand new stethoscopes and tendon hammers. 3 years of Clerkship followed BUT wait!! Clerks sit down and work, we STOOD for 3 years! Now I understand why my knees hurt whenever I stand for long now. Students nowadays do NOT understand the meaning of the word "TERROR", nope you do not until you are selected by the drawing of straws to present the Long Case to Prof Danaraj. Now that's pure terror. The good Professor's expectation of History is so detailed that War and Peace would look like a short story in comparison. His expectation of our physical examination is so complete that THE ENTIRE Tally's that you all use today will seem inadequate in his eyes. THE PATIENT IS ALWAYS COMPLETELY EXAMINED, a concept today's students simply fail to grasp to my eternal irritation. And the tendon hammer will whisk about freely like a conductor's baton, occasionally landing on our thighs as a reward for a really ignorant answer! My stomach probably developed gastritis from the ward rounds and clinics of Prof Florence Wang, it was interminable as she patiently spoke to EVERY patient in the ward and clinic, examined every patient personally NO MATTER who did so
beforehand and then grilled the Houseman and students in the entourage. She taught me that while it is important to treat the patient's physical illness, it is even more important to treat the patient's mind and show him/her that you care. Treat the Human being, not just the disease. In surgery, the teachers constantly reminded me that my knowledge of anatomy is as low as "the skin of a pig's belly"... aka NEXT TO NUTHIN! Ok thats one reason I chose Internal Medicine. In Psychiatry we had a lecturer who wore a BLUE shirt for all the years that we were at Uni! And Prof Deva will ask and ask and ask "WHY". Patient cannot sleep sir....... WHY?, Because he feel stressed sir..... WHY?, because his business has problems sir.... WHY?..... et infinitum. And in Paediatrics Prof Lam will literally JUMP up and Down on the spot whenever we do something or say something "STUPID"! "This child was apparently well until….". "Just because the ^%*_+ Hutchison says that you start the presentation that way, you mindlessly can ONLY do it that way!!!!" JUMP3! And Prof Sinnathuray of OG will literally STAND at the entrance to catch all the students who came late! Half my students today will be queuing at the Dean's office today to explain if we follow the same methods! Now we have a sweet counsellor to slowly talk sense into them. So much for why your brain damaged tutor today FREAKS out when the students come late, not know their basic sciences, or do a physical examination so ANAEMIC that Pernicious Anaemia seems more pink! It is really because of the software fed into me that refuses to move into the 21st century.
30) On Rheumatoid Factor Dear Yin Ling, in 39 days you will sit for your exams. I will expedite all that I can do to help you revise. I will even answer my own questions! RF is a very common test. Rheumatoid factor is an immunoglobulin which can bind to other antibodies. Rheumatoid factor is found in about 1-‐2% of healthy people. The incidence of rheumatoid factor increases with age and about 20% of people over 65 years old have an elevated rheumatoid factor. That is why it is so commonly seen as positive in screening blood tests in the elderly. High titers of rheumatoid factor are associated with more severe rheumatoid arthritis. The factor also has been associated with a higher tendency to develop the non-‐joint complications of the disease such as rheumatoid nodules and rheumatoid lung disease. Rheumatoid factor is present in about 80% of adults (but a much lower proportion of children) with rheumatoid arthritis. It is also present in patients with other connective tissue diseases such as systemic lupus erythematosus and Sjögren's syndrome, and some with infections diseases including infectious hepatitis. Test: One method mixes the patient's blood with tiny latex beads covered with human antibodies (IgG). The latex beads clump or agglutinate if rheumatoid factor (IgM RF) is present. A rheumatoid factor titer more than 1:80 is indicative of rheumatoid arthritis but may also occur in other conditions. False positive results can occur when the blood is high in fats. A negative test result for rheumatoid factor does not exclude the diagnosis of rheumatoid arthritis. The presence of this marker is not, however, needed to make the diagnosis of rheumatoid arthritis. In fact 15-‐25 percent of all patients with rheumatoid arthritis do not have rheumatoid factor in their serum. There is no conclusive laboratory test which confirms the diagnosis of rheumatoid arthritis.
Patients are often times fearful, when their doctor tells them that a rheumatoid factor (RF) was found on routine laboratory testing. Immediately, they assume that they have developed rheumatoid arthritis (RA). This is simply not the case. Anti-‐citrullinated protein antibody (ACPA) is a better tool for identifying rheumatoid arthritis than rheumatoid factor levels Now remember the old British car MG and you will remember its IgM against IgG!!!
Dr Hu : What is “seronegative’ stand for ? What is seronegative arthritis ? (Please take note, rheumatoid arthritis (RA) is not included as seronegative arthritis even it can be seronegative.). “Rheumatoid factor (RF) & Antibodies against Cyclic Citrullinated Peptides (ACCP) have less sensitivity in the diagnosis of early disease phase of RA.” At present, RA is diagnosed based on fulfillment of the classification criteria set by the American College of Rheumatology (ACR), which have recently been revised by a joint ACR and EULAR committee. In the revised criteria, objective serological testing for the presence of 2 RA disease markers, rheumatoid factor (RF) and antibodies directed against cyclic citrullinated peptides (ACCP), is included as an important criterium. However, according to recent meta-‐analyses, approximately one-‐third of established RA patients are seronegative for these 2 diagnostically applied disease markers. Moreover, the sensitivities of both markers for RA are reported to be even lower in
the diagnostically important early disease phase. “Extra-‐articular/systemic manifestation can appear in early stage of RA” Extra-‐articular manifestation usually develop in patients with long term and severe RA, however, in some cases systemic manifestation such as interstitial pulmonary diseases, pleuritis or pericarditis can appear in “early” stages of the disease. “ RA also can has positive ANA/anti-‐double-‐stranded (anti-‐ds) DNA”. Antinuclear antibodies (ANA) and anti-‐double-‐stranded (anti-‐ds) DNA antibodies may be present in patient with RA, although, the physicians have to be aware that treating RA with anti-‐TNF monoclonal antibodies infliximab can increase serum levels of ANA and anti-‐ds DNA. “CRP more specific than ESR in measure disease activity” Typically, acute phase reactants such as sedimentation rate (ESR) and reactive C protein (CRP) are used to measure the disease activity. These are markers of the systemic acute inflammatory response, however, CRP levels are more specific for RA compared with the erythrocyte sedimentation rate (ESR) levels, since CRP are more correlated with higher levels of pro inflammatory cytokines, such as interleukin (IL)−6 and TNF-‐α and related with radiological progression.
31) on WATER AND ELECTROLYTES Dear Yin Ling, Every year I ask the students as to how much urine they produce in a day.... and every year I am AMAZED that not a few have NO CLUE! You know of course that Water and Na balance are closely interdependent. Total body water (TBW) is about 60% of body weight (ranging from about 50% in obese people to 70% in lean people; I keep telling auntie that it is ok for me to run in the rain to the car as I am 70% water!). Almost 2/3 of TBW is in the intracellular compartment (intracellular fluid); the other 1/3 is extracellular (extracellular fluid). Normally, about 25% of the ECF is in the intravascular compartment; the other 75% is interstitial fluid. Total body water = 70 kg × 0.60 = 42 L. The major intracellular cation is K, with an average concentration of 140 mEq/L. (To remember think of Na concentration in blood). The extracellular K concentration is ONLY 3.5 to 5 mEq/L. Do realise the HUGE Gradient! The major extracellular cation is Na, with an average concentration of 140 mEq/L and an intracellular Na concentration of 12 mEq/L. The Na-‐K exchange pump is super duper efficient to maintain this gradient. Osmotic forces: The concentration of combined solutes in water is osmolarity (its in simple words the amount of solute per L of solution la), which, in body fluids, is similar to osmolality (amount of solute per kg of solution). Words words words... a litre of fluid is about 1 kg ma! Hence, Plasma osmolality can be estimated according to the formula Plasma osmolality (mOsm/kg) = Na + Glucose + Urea where serum Na is expressed in mEq/L and glucose and BUN are expressed in mg/dL. OLD UNITS. These are the BIG BOYs ma.
Whose the Number 1 badminton player in the world? Chong Wei, everyone knows right! Whose no 2? Lin Dan right! Now whose no 3?? Errrr Errrr. Only the big boys are BIG, the rest cannot remember! Same in Blood! Remember the BIG BOYs! Your blood when you bite your tongue is SALTY! Thats the Chong Wei! If you are diabetic it may be sweet lorr. Thats Lin Dan and of course as Renal failure comes, Urea is a BIG player now. Osmolality of body fluids is normally between 275 and 290 mOsm/kg. Na is the major determinant of serum osmolality. An osmolar gap is present when measured osmolality exceeds estimated osmolality by ≥ 10 mOsm/kg. When this happens, there is a DARK HORSE!! Someone has crept in and upset the RANKING ORDER! WHO IS THAT you must ask! It is caused by unmeasured osmotically active substances present in the plasma. The most common are alcohols (ethanol, methanol, isopropanol, ethylene glycol), mannitol and glycine. From the formula you can see how Urea affects the osmolality in the ESRF patient. Water crosses cell membranes freely from areas of low solute concentration to areas of high solute concentration. Thus, osmolality tends to equalize across the various body fluid compartments, resulting primarily from movement of water, not solutes. Note that Solutes such as urea that freely diffuse across cell membranes have little or no effect on water shifts (little or no osmotic activity), whereas solutes that are restricted primarily to one fluid compartment, such as Na and K, have the greatest osmotic activity. Water intake and excretion: The average daily fluid intake is about 2.5 L. ( Note the IVD regimes we use when a patient is "Nil by mouth! How much fluid do we give??) In the normal resting state, input of water through ingested fluids is approximately 1200 ml/day, from ingested foods 1000 ml/day and from metabolism 300 ml/day, totaling 2500cc/day. Note the magic number! The amount needed to replace losses from the urine and other sources is about 1 to 1.5 L/day in healthy adults. (Most of you are smart to carry a 1000cc bottle!) However, on a short-‐term basis, an average young adult with normal kidney
function may survive on as little as 200 mL of water each day to excrete the nitrogenous and other wastes generated by cellular metabolism. The urine will be very concentrated! More is needed in people with any loss of renal concentrating capacity. If we are to use urine output as a means of judging adequate hydration status, this firstly assumes that the renal function is NORMAL. If we see at least 1-‐1.5cc of urine output a minute, this is reassuring of adequate provision of fluids. At 1cc a minute, we expect 60cc an hour and about 1500cc per day. This is about the average urine output for an adult. When we do not drink or is not on IVD, the kidneys will concentrate our urine as you will notice in the urine that you pass on waking up; its concentrated after not drinking for 7-‐8 hours of sleep. Renal concentrating capacity is lost in -‐The elderly -‐Patients with diabetes insipidus, certain renal disorders, hypercalcemia, severe salt restriction, chronic overhydration, or hyperkalemia -‐People who ingest ethanol, phenytoin, lithium, or amphotericin B -‐People with osmotic diuresis (eg, due to high-‐protein diets or hyperglycemia) Other obligatory water losses are mostly insensible losses from the lungs (about 500cc) and skin (depending on ambient temperature and humidity, it varies from 300 onwards), averaging about 650 to 850 mL/day in a 70-‐kg adult. Sweat losses can be significant during environmental heat exposure (like in the last few days; notice my water bottle empties fast to replace my sweat in the wards) or excessive exercise. With fever, another 50 to 75 mL/day may be lost for each degree C of temperature elevation above normal. Assuming a loss of about 800cc from breathing and sweating PLUS whatever little urine is passed by the ESRF patient on HD, that is his allowed water intake per day. GI losses are usually negligible, except when vomiting, diarrhoea, or both occur. Water intake is regulated by thirst. Thirst is triggered by receptors in the anterolateral hypothalamus that respond to increased serum osmolality (as little as 2%) or decreased body fluid volume. Rarely hypothalamic dysfunction decreases the capacity for thirst.
Water excretion by the kidneys is regulated primarily by ADH (vasopressin). ADH is released by the posterior pituitary and results in increased water reabsorption in the distal nephron. ADH release is stimulated by any of the following: Increased serum osmolality Decreased blood volume Decreased BP Stress!! Remember this! A patient post surgery, septic or in my Long Case class or worse BEDSIDE Class will have increased ADH output. (I cannot understand why some students keep going to the toilet, better check your renal function!) ADH release may be impaired by certain substances (eg, ethanol, phenytoin) and central diabetes insipidus Water intake decreases serum osmolality. Low serum osmolality inhibits ADH secretion, allowing the kidneys to produce dilute urine.
32) ON BILIRUBIN METABOLISM Dear Yin Ling, when we see a patient with jaundice, the physiology of Bilirubin metabolism must be at the back of our minds in order to think of differential diagnosis. This separates medicine from quackery. Not all jaundice is due to liver diseases and liver diseases are not always accompanied with jaundice!!
Bilirubin, a physiological product of RBC, is metabolized in the liver and excreted into bile ducts; an appearance of jaundice means that there is a breakdown of balance of bilirubin metabolism and the patient may have a problem in the liver, or RBC production and destruction, or excretion of bilirubin. eg hemolytic diseases: Always keep it in mind when managing a patient with jaundice. Bilirubin is an end product of heme metabolism, coming mainly, 70 ~ 80 %, from hemoglobin of senescent red blood cells; it splits to heme and globin, then further split to iron and biliverdin, and the biliverdin converts to bilirubin. Bilirubin combines with albumin in the blood stream, only separated just before being uptaken into liver cells. The bilirubin in the hepatocytes conjugates with glucuronic acid to become conjugated bilirubin, which is excreted to the biliary tract and intestines and finally excreted. The bilirubin from hemoglobin is free unconjugated bilirubin in the blood stream and is not soluble in water. After being taken into hepatocytes, it is converted to soluble conjugated form and excreted into bile ducts. The bilirubin is divided into two types, direct reacting bilirubin and indirect reacting bilirubin, according to its mode of reaction during the test process. It can be recognized that direct reacting bilirubin is the conjugated bilirubin and the indirect reacting bilirubin as unconjugated bilirubin. Conjugated bilirubin is absorbed in the distal portion of the ileum after its hydrolyzed and converted to URObilinogen by the intestinal pathogens. About 15 ~ 20 % of the urobilinogen is reabsorbed from the intestine into portal veins and finally 90% of them return to the liver and is re-‐excreted in the bile, the entero-‐hepatic circulation of bilirubin. The remaining 10 % gets into the systemic circulation and finally excreted in the urine through kidney. Thus urine urobilinogen increases in hemolytic disease. Hyperbilirubinemia -‐-‐ jaundice occurs when the bilirubin balance between production and excretion breaks down. the possible causes of hyperbilirubinemia: 1. over production of bilirubin from hemolysis 2. the impairment in bilirubin uptake and conjugation in the liver, 3. impaired excretion from the liver cells or the liver
4. the unconjugated and conjugated bilirubin that is leaked into the blood stream from damaged liver cells. High-‐unconjugated-‐bilirubinemia (1) Overproduction: Normal liver can handle the amount of seven times of normal daily bilirubin production. When the production of bilirubin is increased due to hemolysis and and Ineffective erythropoiesis beyond the ability of normal liver to handle, the serum indirect bilirubin will increase and this is prehepatic jaundice. AST, ALT and Alk-‐P, that reflect the damage of hepatocytes will remain normal and predominantly indirect bilirubin is increased. Note that The conjugated bilirubin may increase slightly because of the high turnover. (2) Abnormality in uptake and conjugation: Serum indirect bilirubin may increase when there is problems of uptake and conjugation in the liver cells of bilirubin. This is non-‐hemolytic unconjugated hyperbilirubinemia. Crigler-‐Najjar syndrome (congenital non-‐hemolytic jaundice) is caused by the deficiency of glucuronyl transferase. The symptoms will appear in the infant stage, and there are two types, Type I is more severe than Type II, and may induce kernicterus. Gilbert's syndrome or idiopathic unconjugated hyperbilirubinemia is caused by the similar mechanism as Crigler-‐Najjar syndrome, and only different in degree. High-‐conjugated-‐bilirubinemia: unconjugated-‐bilirubin conjugates with glucuronic acid to become conjugated-‐ bilirubin. When transportation of conjugated-‐bilirubin is impaired in the liver during the excretion process from liver cells or during passage from bile ductules, the condition is called cholestatic jaundice. (1) Intrahepatic causes of cholestasis:
The jaundice in drug-‐induced hepatitis and in pregnancy is intra-‐hepatic cholestasis. Dubin-‐Johnson Syndrome and Rotor Syndrome are congenital causes of intrahepatic cholestasis. The increase of serum bilirubin is mainly conjugated-‐bilirubin, and Rotor syndrome is considered as a variant of Dubin-‐Johnson syndrome. Morphologically, melanin pigments deposit in the liver cells are noted in Dubin-‐Johnson syndrome but not in Rotor Syndrome. Primary biliary cirrhosis shows obstruction of biliary ductules and inter-‐lobular bile ductules. Primary/secondary sclerosing cholangitis will induce hyper-‐conjugated-‐ bilirubinemia. In hepatocyte diseases, i.e. acute and chronic liver diseases including cirrhosis, the uptake, conjugation and excretion of bilirubin in the hepatocytes are impaired and induce an intra-‐hepatic cholestasis. Therefore, the serum bilirubin elevation is a mixed type. (2) Extrahepatic cholestasis: Stones, parasites, tumours in the biliary tract, biliary obstruction due to external compression from Ca Pancreas will induce elevation in serum conjugated-‐bilirubin. No conjugated bilirubin is present in normal urine. Only conjugated-‐bilirubin will pass through renal glomeruli. Serum level of bilirubin does not parallel to the amount of urinary bilirubin. Urobilinogen-‐ only a small part of urobilinogen absorbed from the intestinal tract is excreted out of the body through the kidney, and most of the urobilinogen return to the liver and are re-‐excreted to the intestinal tract. The amount of urinary urobilinogen is affected by the amount of conjugated-‐ bilirubin in the biliary duct and also intestinal pathogens that convert bilirubin to urobilinogen. Urobilinogen is a colourless product of bilirubin reduction. This constitutes the "enterohepatic urobilinogen cycle". Increased amounts of bilirubin are formed in haemolysis, which generates increased
urobilinogen in the gut. In liver disease (such as hepatitis), the intrahepatic urobilinogen cycle is inhibited also increasing urobilinogen levels. Urobilinogen is converted to the yellow pigmented urobilin apparent in urine. The urobilinogen is reduced to stercobilinogen in the intestine and is then oxidized to brown stercobilin, which gives the feces their characteristic color. In biliary obstruction, below-‐normal amounts of conjugated bilirubin reach the intestine for conversion to urobilinogen. With limited urobilinogen available for reabsorption and excretion, the amount of urobilin found in the urine is low. High amounts of the soluble conjugated bilirubin enter the circulation where they are excreted via the kidneys. These mechanisms are responsible for the dark urine and pale stools observed in biliary obstruction. Low urine urobilinogen may result from complete obstructive jaundice or treatment with broad-‐spectrum antibiotics, which destroy the intestinal bacterial flora. (Obstruction of bilirubin passage into the gut or failure of urobilinogen production in the gut.)
33) on LIVER ENZYMES My dear yin ling, ALT, an enzyme in liver cells, with lesser amounts in the kidneys, heart, and skeletal muscles, and is a relatively specific indicator of acute liver cell damage. When such damage occurs, ALT is released from the liver cells into the bloodstream, often before jaundice appears, resulting in abnormally high serum levels that may not return to normal for days or weeks. In combination, ALT and AST are two of the most reliable markers of hepatocellular injury or necrosis. Of the two, ALT is more specific for hepatic injury because it is present mainly in the cytosol of the liver and in low concentrations elsewhere. AST has cytosolic and mitochondrial forms and is present in tissues of the liver, heart, skeletal muscle, kidneys, brain, pancreas, and lungs, and in white and red blood cells. Markers for high alcohol consumption are carbohydrate deficient transferrin (CDT), gamma glutamyl transferase (GGT) and aspartate aminotransferase (AST). BUT Most have fairly low sensitivities and specificities An elevated serum AST in relation to serum ALT (alanine aminotransferase) is likely an indicator that alcohol has induced liver damage. Thus, when AST/ALT ratio is >1.5, this is considered as highly suggestive that alcohol is the cause of the patient's liver pathology. However, many patients who doubtless consume high amounts of alcohol and indeed are alcohol-‐dependent and display elevated serum aminotransferase levels do not show a high AST/ALT ratio. This suggests that additional factors lead to the high AST/ALT ratio seen in some patients. One such factor may be the severity of the liver disease. The well-‐recognised high AST/ALT ratio in alcoholic liver disease is, in fact, predominantly found in patients whose disease is advanced. Different, to some extent possibly interrelated, reasons have been reported for the high AST/ALT ratio in alcoholic liver disease: i) a decreased hepatic ALT activity as healthy hepatocytes decrease; ii) pyridoxal 5ʹ′-‐phosphate depletion in the livers of alcoholics; and
iii) mitochondrial damage leading to an increase in serum activity of mitochondrial aspartate in patients with high alcohol consumption leading to high AST. BUT Most patients with high alcohol consumption do not have an AST/ALT ratio above 1. Hence, remember that a high AST/ALT ratio is suggestive of advanced alcoholic liver disease, not just alcoholism. Liver DAMAGE is seen with increased AST/ALT ratio in patients. This has also been associated with the development of cirrhosis in Nonalcoholic Steatohepatitis. Furthermore, a high AST/ALT ratio in patients with increased serum aminotransferases has been reported in chronic viral hepatitis, possibly due to the same reasons. ALT is present mainly in the cytosol, while AST in the mitochondrias. During events of INFLAMMATION, as hepatocyte cell wall integrity breaks down, ALT will increase much much more than AST, eg in viral hepatitis. ALT testing helps detect and evaluate progress and treatment of acute hepatic disease, especially hepatitis, and cirrhosis. Very high ALT levels (up to 50 times normal) suggest viral or severe drug-‐induced hepatitis, or other hepatic disease with extensive damage of liver cells. (AST levels are also elevated but usually to a lesser degree.) Moderate-‐to-‐high levels may indicate infectious mononucleosis, chronic hepatitis, intrahepatic cholestasis or cholecystitis, early or improving acute viral hepatitis, or severe hepatic congestion due to heart failure. Slight-‐to-‐moderate elevations of ALT (usually with higher increases in AST levels) may appear in any condition that produces acute hepatocellular (liver cell) injury, such as active cirrhosis, and drug-‐induced or alcoholic hepatitis. Marginal elevations occasionally occur in acute myocardial infarction (heart attack), reflecting secondary hepatic congestion or the release of small amounts of ALT from heart tissue. However in the events of CELL DEATH, AST will predominantly increase as cell
death release the AST enzymes from the mitochondria eg in liver cirrhosis, and myocardial infarct. AST levels fluctuate in response to the extent of cellular necrosis and therefore may be temporarily and minimally elevated early in the disease process, and extremely elevated during the most acute phase. Depending on when the initial sample was drawn, AST levels can rise-‐ indicating increasing disease severity and tissue damage-‐ or fall-‐ indicating disease resolution and tissue repair. Thus, the relative change in AST values serves as a reliable monitoring mechanism. May this little yet important concept helps in your future LFT interpretation. 34) ON REFLEXES Dear Yin Ling, The NORMAL Superficial reflexes Superficial reflexes are motor responses to scraping the skin. They are graded simply as present or absent and markedly asymmetrical responses would be considered abnormal. These reflexes are VERY different from the muscle stretch reflexes in that the sensory signal has to not only reach the spinal cord, but also must ascend the cord to reach the brain. The motor limb then has to descend the spinal cord to reach the motor neurons . As can be seen from the description, this is a polysynaptic reflex. This can be abolished by lower motor neuron damage or destruction of the sensory pathways from the skin that is stimulated. However, the utility of superficial reflexes is that they are decreased or abolished by conditions that interrupt the pathways between the brain and spinal cord (such as with spinal cord damage). Classic examples of superficial reflexes include the abdominal reflex, the cremaster reflex and the normal plantar response. The abdominal reflex includes contraction of abdominal muscles that is stimulated
by scraping the skin superficially and rapidly along a dermatome towards the umbilicus . This contraction can be seen as a brisk contraction of the abdominal muscles with the umbilicus moving towards the stimuli. The cremaster reflex is produced by scratching the skin of the medial thigh, which should produce a brisk and brief elevation of the testis on that side.
The normal plantar response occurs when scratching the sole of the foot from the heel along the lateral aspect of the sole and then across the ball of the foot to the base of the great toe. This normally results in flexion of the great toe (a "down-‐going toe") and, indeed, all of the toes. The "anal wink" is a contraction of external anal sphincter when the skin near the anal opening is scratched. This is often abolished in spinal cord damage (along with other superficial reflexes ). And Now the "Pathological reflexes" The best known (and most important) of the so-‐called "pathological reflexes" is the Babinski response (upgoing toe; extensor response). The full expression of this reflex included extension of the great toe and fanning of the other toes . It is actually a superficial reflex that is elicited in the same manner as the plantar response (i.e., scratching along the lateral aspect of the sole of the foot and then across the ball of the foot toward the great toe). This is a primitive withdrawal type response that is normal for the first few months of life and is suppressed by supraspinal activity sometime before 6 months of age. Damage to the descending tracts from the brain (either above the foramen magnum or in the spinal cord) promotes a return of this primitive protective reflex, while at the same time abolishing the normal plantar response. The appearance of this reflex suggests the presence of an upper motor neuron lesion.
35) ON SLE Dear yin ling, This I hope will help you remember O-‐ Oral ulcer R-‐ malar Rash D-‐ Discoid rash E-‐ Exaggerated photosensitivity R-‐ Renal disorders (proteinuria, cellular casts) H-‐ Haematology disorders (haemolytic anemia, leukopenia, lymphopenia, thrombocytopenia) I-‐ Immunological disorders (anti-‐DNA antibody, anti-‐Sm, antiphospholipid antibody) S-‐ Serositis A-‐ ANA N-‐ Neurological problems A-‐ Arthritis 1. 95% of SLE are ANA +ve. 2. 50% dsDNA +ve, but is specific for SLE. 3. 25% RF +ve. Prof Esha : Even if you forget the pnemonic, remember there are 4 mucocutaneous features,(malar rash,photosensitive rash,discoid rash and oral ulcer),4 systemic involvement( CNS,serositis,kidney and arthritis) and 3 lab finding( Heamatology,Immunology and ANA stands on its own) Recent addition in lab features are positive anti Sm antibody,antiphospholipis antibody,and low complements,along with direct positive coomb's test. 36) ON MONOFILAMENT testing Dear Yin Ling, Are you familiar with Monofilament sensory testing devices which consist of a single strand of nylon (typically attached to a plastic or paper handle) that can produce a
characteristic downward force when buckled onto a surface? Are you aware that they come in different sizes? The monofilaments commonly used to screen for sensory neuropathy are 4.17, 5.07, and 6.10. The use of a single 5.07 monofilament is the accepted standard in medical practice to screen for the minimum level of protective sensation in the foot. Ten grams of reproducible buckling stress force are required to bend the 5.07 monofilament. Why do we use monofilament testing? Why do we not just use our usual pin, cotton and tuning fork?? When the monofilament bends, its tip is exerting a pressure of 10 grams (therefore this monofilament is often referred to as the 10gram monofilament). If the patient cannot feel the monofilament at certain specified sites on the foot, he/she has lost enough sensation to be at risk of developing a neuropathic ulcer. Testing of diabetic patients for protective sensation may be simplified to testing under both first metatarsal heads. If a patient cannot sense the application under either first metatarsal head, he or she probably has lost protective sensation and should be considered to be at risk for undetected injury. Generally, No person with a foot ulceration could feel the 5.07 (10g) filament, concluding that monofilaments are an effective, inexpensive and simple screening device in identifying the ‘at risk’ foot.\ In contrast, a person who can feel the 10-‐gram filament in the selected sites is at reduced risk for developing ulcers. The patient must not watch while the examiner applies the filament. Pre-‐Test the monofilament on the patient's hand or sternum so he/she knows what to anticipate. Typically we test five sites and document the findings. The number of sites may vary from centre to centre. Apply the monofilament perpendicular to the skin's surface Apply sufficient force to cause the filament to bend or buckle Pls Apply the filament along the perimeter and NOT ON an ulcer, callus, scar or necrotic tissue. Do not allow the filament to slide across the skin or make repetitive contact at the test site.
Have patients identify at which time they were touched. To avoid guessing, randomize the sequence of applying the filament throughout the examination. Patients should have their feet examined at least annually for impaired sense of pressure, vibration, pain, or temperature, which is characteristic of peripheral neuropathy. Pressure sense is best tested with a monofilament esthesiometer as this picks up patients with high risk of diabetic ulcers
Yin Ling, The overall risk of developing a diabetic foot ulcer is determined by a combination of factors. In general, the risk is higher if: Neuropathy is more severe (because more sensation is lost and multiple small trauma breaks the skin) Peripheral vascular disease is more severe (because there is less circulation to bring enough oxygen to repair tissue damage. Just look at the dry black feet with curled up nails and you see feet which are deserts) There are coexisting abnormalities of the shape of the foot which make the local effects of neuropathy or vascular disease more severe (because it increases local pressure and callus; heavens let us ban all those fashionable but cruel footwear that ladies wear as it deforms the feet into an abnormal shape) The patient who is unable to practise reasonable self care of the feet and to prevent
trauma (because there are more chances of damaging the feet with fungal infections in the webs, poor nail hygiene and cutting) The diabetic control is very poor (because of susceptibility to infection and poor wound healing) There is a past history of foot ulceration due to diabetes (because all the above factors persist) Dear Yin Ling, People often ask which is the earliest abnormality and expect a single answer that is dogmatic. The truth is however much more complex and the answer is "It varies!" Sensory or sensorimotor distal polyneuropathy is the most common of the diabetic neuropathies. With this, numbness and paresthesias begin in the toes, and gradually and insidiously ascend to involve the feet and lower legs. Very common, we see it all the time. With a sensory or sensorimotor distal polyneuropathy, both lightly myelinated and unmyelinated small nerve fibers and the myelinated large nerve fibers are affected. Small and large fiber dysfunction occurs in varying combinations; however, in most cases, the earliest deficits involve the small nerve fibers. Features characteristic of a small fiber peripheral neuropathy include burning or lancinating pain, hyperalgesia, paresthesias and dysesthesias, **deficits in pain and temperature perception** leading to foot ulceration. Features characteristic of large fiber peripheral neuropathy include the loss of position and vibration perception sense and loss of deep tendon reflexes, tested with tuning fork and Ankle jerks. So based on this what will you, yin ling, select as a mode for screening which must of course pick up the pathology early!?
37) ON ISOLATED RAISED GAMMA GT Dear YL, Raised Gamma GT in isolation is a very common finding It is From hepatocytes and biliary epithelial cells, pancreas, renal tubules and intestine. Very sensitive but Non-‐specific It is Raised in ANY liver disease hepatocellular or cholestatic But Usefulness is limited It helps Confirm hepatic source for a raised ALP Alcohol induces it As it is an Easily Induced enzyme-‐ many Drugs elevates it *Pls note that an Isolated increase does not require any further evaluation, suggest watch and rpt 3/12 and only if other LFT’s become abnormal then investigate 38) ON PCM TOXICITY Dear YL, Are you aware that Paracetamol toxicity can occur in much lower doses in certain circumstances eg Alcohol use Fasting state-‐ Depletion of glutathione Beware of overdosing in the fasting patient with pain eg. post surgery!!! So if you jog, get dehydrated, low glutathione now and have muscle aches for which you take PCM, you may have liver damage!! 39) ON ALCOHOL Dear Yin Ling, our Muslim friends are absolutely right with alcohol prohibition. And the Buddhist Precepts also do not allow Alcohol consumption. Alcohol, a very simple molecule is probably the most widely used drug in the world. It is distributed to all the organs and fluids of the body, but it is in the brain that alcohol exerts most of its effects. Like other general anesthetics, alcohol is a central
nervous system depressant. In general, its effects are proportional to its concentration in the blood. Yin Ling, How does the body handle alcohol? Alcohol is rapidly absorbed from the gastrointestinal tract into the bloodstream and from there it is distributed throughout the other bodily fluids and tissues. Alcohol is principally metabolized by the liver into acetaldehyde, with the remainder being excreted in the urine. On average, it takes the liver about an hour to break down one unit of alcohol -‐-‐ the amount typically found in 12 ounces of beer, 4 ounces of wine or one ounce of 50 proof hard liquor. Blood alcohol levels decline at a fixed rate irrespective of the amount consumed. The more consumed, the longer it takes to be metabolized. Additionally, blood levels are greatly, and inversely, influenced by body weight. The thinner you are, the greater the alcohol blood level for any given amount of alcohol consumed. Because of these factors, blood levels may remain elevated for many hours after the last drink. Alcohol may impair temperature regulation both in the cold, and in the heat, in countries with extreme climates, this can kill. It is also a potent diuretic and this may lead to dehydration. Yin Ling, What are the long term adverse effects of alcohol? The chronic abuse of alcohol may cause numerous adverse health effects which include: Chronic alteration of brain and nerve function Weakening of heart muscle Testicular shrinkage and male breast enlargement Impotency Elevated triglycerides Fat deposits in the liver Cirrhosis and liver failure Blood-‐clotting abnormalities Pancreatitis Vitamin deficiencies
Chronic skin alterations Death Chronic moderate ethanol ingestion by young female mice results in decreased fertilization, embryo growth retardation, and abnormal embryo development in vitro. The cardiovascular consequences of heavy ethanol consumption are several. If ethanol exposure occurs prenatally at a period when the heart of the infant is developing, then structural damage is observed and manifests as diminished capacity of the heart to function properly. If the cardiovascular system is exposed to excessive ethanol later in life, then a variety of problems can manifest, most prominently are cardiomyopathy, hypertension, stroke and cardiac arrhythmias. Cardiac arrhythmias have been observed after both acute intake of large amounts of ethanol and after chronic alcohol consumption. For example, ethanol intake over a long weekend may result in electrophysiological anomalies referred to as "holiday heart syndrome", whereas sudden cardiac death has been associated with alcoholism. A number of hypotheses have been advanced to explain the disturbances in cardiac rhythms. These include scarring of the heart muscle, alterations in the chemicals, which influence heart function such as electrolytes and catecholamines, and alterations in the amount of oxygen coming to the heart. There appear to be several mechanisms by which ethanol can lead to cardiomyopathy. These include the following: 1. an alteration in the flow of calcium ions in the cardiac muscle, which in turn reduces the efficiency by which calcium activates muscle contraction; 2. modification of the action of contractile proteins, actin and myosin; 3. reduction in the synthesis of proteins needed for contraction and energy; 4. an influence of deleterious ethanol metabolites (acetaldehyde) and free radicals; and 5. activation of genes which may promote cell death. Yin Ling, does alcoholism cause Cancer? Consumption of alcoholic beverages is causally related to cancers of the mouth, pharynx, larynx and esophagus and that studies indicate that the risk is most pronounced among smokers and at the highest levels of consumption.
There is evidence that suggests a link between alcoholic beverage consumption and cancer of the liver and breast. There are some circumstances under which diabetics should not drink alcohol in any amount. The key for those with diabetes is to understand what conditions can be worsen if they consume alcohol. According to the American Diabetes Association, drinking alcohol is a poor choice if diabetics have the following conditions: Nerve damage in the arms or legs. Diabetic eye disease. High blood pressure. High levels of triglycerides. Alcohol can damage nerve cells; even light drinking can cause nerve damage. For diabetics with nerve damage drinking can increase the pain, numbness, tingling or burning sensation associated with diabetic nerve damage. For diabetics with eye disease symptoms, heavy drinking can make the condition worse and heavy drinking is defined as three or more drinks during one day. Diabetics who also have high blood pressure should also not drink alcohol. Pls remember that Alcohol increases the amount of triglycerides in the blood. Even very light drinking, defined as two drinks a week, can increase triglyceride levels. Diabetics who have high triglycerides should not drink alcohol at all. Yin Ling, what are the Sexual effects of alcohol? Soon after consuming alcohol, is found the following common effects: Alcohol has a “disinhibiting” effect, which can make people “loosen up” and feel more comfortable initiating or engaging in sex. Alcohol may make you feel more socially confident and in small quantities may facilitate more socializing and sexual communication. In small amounts alcohol has been reported to have a positive impact on sexual desire and arousal. At the same time, research shows that even after a few drinks sexual response is reduced. In large amounts alcohol makes sex difficult to impossible. While in moderate amounts alcohol can have an impact on engaging in risky sexual behavior, although this impact is not fully understood.
As drinking increases both men and women will experience a reduction in sexual arousal, men may have difficulty getting erections, and both men and women may have difficulty experiencing orgasm. yin ling, what are the Long term sexual effects of alcohol? Chronic alcohol abuse, or alcoholism, inevitably has a devastating effect on sexuality, including: Erectile disorders and dysfunction in men Loss of sexual desire, significant decrease in sexual arousal for men and women Difficulty experiencing orgasm for men and women Yin Ling, what causes Flushing in some people after drinking alcohol? Studies of autopsy liver specimens from individuals of different racial groups revealed a polymorphism in alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). About 85% of the Japanese livers had an atypical ADH and 52% of the livers an unusual ALDH. Data on the distribution of phenotypes in random European and Japanese population as well as family studies suggest a direct relationship between the lack of low Km isozyme of ALDH and alcohol-‐induced biological sensitivity. Alcohol sensitivity is quite common in individuals of Mongoloid origin and might be due to delayed oxidation of acetaldehyde by an unusual type of ALDH. Many people of East Asian descent have a mutation in their alcohol dehydrogenase gene that makes this enzyme unusually effective at converting ethanol to acetaldehyde, and about half of such people also have a form of acetaldehyde dehydrogenase which is less effective at converting acetaldehyde to acetic acid. This combination causes them to suffer from the alcohol flush reaction, in which acetaldehyde accumulates after drinking, leading to severe and immediate hangover symptoms.
But it is Not just alcohol which causes flushing! Pls think of other causes as well!
40) ON BENCE JONES PROTEIN Dear YL,
not many medical students know about this test now. When I was a student, Prof Florence Wang would make us take urine and test it at the lab ourselves. Hence these are sheared into my memory. Urine is the best specimen in which to look for Bence Jones proteins which if present suggests Multiple Myeloma. Proteins are usually too large to move through a healthy kidney, from the blood into the urine. Bence Jones proteins are an exception. They are small enough to move quickly and easily through the kidney into the urine. A routine dipstick urinalysis will not detect Bence Jones proteins. There are several methods used by laboratories to detect and measure these proteins. The classic Bence Jones reaction involves heating urine to 60°C in a test tube placed in a waterbath. At this temperature, the Bence Jones proteins will clump. The clumping disappears when the urine is further heated to boiling and reappears when the urine is cooled. This simple test will reveal whether or not Bence Jones proteins are present, but not how much is present.
41) ON MYOCARDIAL O2 DEMAND Dear YL, What is Myocardial O2 demand? Myocardial O2 demand is determined mainly by heart rate, systolic wall tension, and contractility, hence narrowing of a coronary artery typically results in angina that occurs during exertion and is relieved by rest. Simple but That's for the stable plaques of course. Q: How did William Heberden describe Classic angina? Pls note a classic-‐ Angina immobilises the patient from whatever he is doing -‐ he/she STOPS! In addition to exertion, cardiac workload can be increased by disorders such as intercurrent illnesses, fever, hypertension, aortic stenosis, aortic regurgitation, or hypertrophic cardiomyopathy. Q: What are the Classical Presentation symptoms of Aortic stenosis? LVH from whatever cause can also decrease relative myocardial perfusion because myocardial mass is increased (causing decreased diastolic flow). A decreased O2 supply, as in severe anemia or hypoxia, can precipitate or aggravate angina. In stable angina, the relationship between workload or demand and ischemia is usually relatively predictable. The great John Hunter predicted that his life is in the hands of any rascals that infuriated him, I assumed he was refering to his med students but nope he died after a hospital board meeting from a massive AMI. Told you faculty meetings are dangerous affairs! As the myocardium becomes ischemic, ventricular function deteriorates. Left ventricular (LV) diastolic pressure usually increases during angina, sometimes inducing pulmonary congestion and dyspnea. Remember 'angina equivalents' ! The exact mechanism by which ischemia produces discomfort is unclear but may involve nerve stimulation by hypoxic metabolites.
Q: What are the limitations of the ECG? The ECG reveals the heart rate and rhythm only during the time that the ECG is taken. A spot picture only The ECG can often be normal or nearly normal in patients with undiagnosed coronary artery disease (false negative results.) On the other hand, many "abnormalities" that appear on the ECG may turn out to have no medical significance (false positive results). Many people with ischaemic heart disease have a normal ECG at rest. During exercise the heart beats faster and needs more oxygen. If one or more of the coronary arteries are narrowed, part or parts of the heart muscle do not get enough oxygen. This can cause the ECG tracing to become abnormal. The degree of abnormality on the exercise ECG tracing can give a good idea of the severity of the disease. Therefore, an exercise ECG test is often done to help to decide if further investigations is needed. But I have colleagues who go straight to a CT angio but that's another story. Because angina resolves quickly with rest, ECG rarely can be done during an attack except during stress testing. If done during angina, ECG is likely to show reversible ischemic changes: T wave inversion, ST-‐segment depression (typically), ST-‐segment elevation (ST-‐segment elevation rather than depression occurs during attack in variant angina), decreased R-‐wave height, intraventricular or bundle branch conduction disturbances, and arrhythmia (usually ventricular extrasystoles). If the ECG is NORMAL despite pain, we can only be confident that the disease is lightly NOT severe and outlook good, but we cannot exclude it if the history is TYPICAL. The resting ECG is often normal in stable angina pectoris in the absence of a previous MI or a cause for LVH. Abnormal ECG changes are more common with unstable angina pectoris. The resting ECG (and usually LV function) at rest is normal in about 30% of patients with a typical history of angina pectoris, even those with extensive 3-‐vessel disease. In the remaining 70%, the ECG shows evidence of previous infarction, hypertrophy, or nonspecific ST-‐segment and T-‐wave abnormalities. In men with chest discomfort suggesting angina, stress ECG testing has a specificity
of 70%; sensitivity is 90%. Sensitivity is similar in women, but specificity is lower, particularly in women < 55 (< 70%). However, women are more likely than men to have an abnormal resting ECG when CAD is present (32% vs 23%). Although sensitivity is reasonably high, exercise ECG can miss severe CAD (even left main or 3-‐ vessel disease). I had an eminent professor who had a 'normal' stress test a week before his fatal infarct. In patients with atypical symptoms, a negative stress ECG usually rules out angina pectoris and CAD; but a positive result may or may not represent coronary ischemia and indicates need for further testing. The HISTORY is the MOST important diagnostic feature, the specificity of ST-‐T and T wave abnormalities is provided more by the clinical circumstances in which the ECG changes are found than by the particular changes themselves. In patients who presents with a history suggestive of AMI within the last 2 -‐ 3 hours, a Normal/Nondiagnostic initial ECG predicts low risk. This is the reassurance of the "Normal finding" but it cannot EXCLUDE the diagnosis, hence we need follow-‐up ECGs, and blood tests. Please realise that 3-‐10% of MI patients have initial normal ECG! Of course, 25% of patients with missed MI had misread ECGs!! It is important to compare with prior ECGs if available for this Increases Specificity! Have a high level of suspicion when facing a typical history and seeing ECG Markers of underlying CAD like Eg Left Ventricular Hypertrophy with or without 'Strain Pattern', ST segment changes; how deep is the ST depression or elevation, T Wave changes, Q Waves in 2 contiguous leads to suggest previous events, Loss of Progression of R waves to suggest previous events, Left Bundle Branch Block or other conduction changes On the other hand, some people have "abnormal" ECGs at baseline but this may be normal for them. It is important that an electrocardiogram be compared to previous tracings. The History cannot be over-‐emphasized for its importance in diagnosis despite all our modern technologies. I hope you learn this well.
42) ON REFLEXES! Dear Yin Ling, Today I demonstrated Hoffman's and Chaddock's sign in a patient to my students at my clinic. The patient's plantar response was equivocal but Chaddock's sign was crystal clear. To my horror the 2 kiddies did NOT know anything about the 2 signs. What are they?? Hoffmann's sign, named after the German neurologist, Johann Hoffmann (born 1857, Rheinhesse; died 1919, Heidelberg), is a finding elicited by a reflex test which verifies the presence or absence of problems in the corticospinal tract. It is also known as the finger flexor reflex. The test involves tapping the nail or flicking the terminal phalanx of the third or fourth finger. A positive response is seen with flexion of the terminal phalanx of the thumb and index finger.
Relation to Babinski sign Hoffmann's sign is often considered the upper limb equivalent of the Babinski's sign because it, like the Babinski sign, indicates upper motor neuron dysfunction. BUT Its mechanism differs considerably from the Babinski which is also known as the plantar reflex; Hoffmann's sign involves a monosynaptic reflex pathway in Rexed lamina IX of the spinal cord, normally fully inhibited by descending input. The pathways involved in the plantar reflex are more complicated, and different sorts of lesions may interrupt them. This fact has led some to reject any analogies between the finger flexor reflex and the plantar response. Superficial reflexes are motor responses to scraping the skin. They are graded simply as present or absent and markedly asymmetrical responses would be considered abnormal.
These reflexes are VERY different from the muscle stretch reflexes in that the sensory signal has to not only reach the spinal cord, but also must ascend the cord to reach the brain. The motor limb than has to descend the spinal cord to reach the motor neurons. This is a polysynaptic reflex. This can be abolished by lower motor neuron damage or destruction of the sensory pathways from the skin that is stimulated. However, the utility of superficial reflexes is that they are decreased or abolished by conditions that interrupt the pathways between the brain and spinal cord (such as with spinal cord damage). Classic examples of superficial reflexes include the abdominal reflex, the cremaster reflex and the normal plantar response. The abdominal reflex includes contraction of abdominal muscles that is stimulated by scraping the skin superficially and rapidly along a dermatome towards the umbilicus. This contraction can be seen as a brisk contraction of the abdominal muscles with the umbilicus moving towards the stimuli. The cremaster reflex is produced by scratching the skin of the medial thigh, which should produce a brisk and brief elevation of the testis on that side. The normal plantar response occurs when scratching the sole of the foot from the heel along the lateral aspect of the sole and then across the ball of the foot to the base of the great toe. This normally results in flexion of the great toe (a "down-‐going toe") and, indeed, all of the toes. The "anal wink" is a contraction of external anal sphincter when the skin near the anal opening is scratched. This is often abolished in spinal cord damage (along with other superficial reflexes ). "Pathological reflexes" The best known (and most important) of the so-‐called "pathological reflexes" is the Babinski response (upgoing toe; extensor response). The full expression of this reflex included extension of the great toe and fanning of the other toes. This is actually a superficial reflex that is elicited in the same manner as the plantar response (i.e., scratching along the lateral aspect of the sole of the foot and then across the ball of the foot toward the great toe). This is a primitive withdrawal type response that is
normal for the first few months of life and is suppressed by supraspinal activity sometime before 6 months of age.
Damage to the descending tracts from the brain (either above the foramen magnum or in the spinal cord) promotes a return of this primitive protective reflex, while at the same time abolishing the normal plantar response. The appearance of this reflex suggests the presence of an upper motor neuron lesion. Chaddock's, Oppenheim, Gordon's are all tested for when the extensor response is equivocal. GORDON'S SIGN : Gordon's sign is a clinical sign in which squeezing the calf muscle elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-‐ like responses. CHADDOCK'S SIGN: Chaddock reflex is a diagnostic reflex similar to the Babinski reflex. It is designed to identify lesions of the pyramidal tract, via stimulation of the skin over the lateral malleolus leading to extension of the big toe.
It was identified by Charles Gilbert Chaddock
Oppenheim's sign is dorsiflexion of the big toe elicited by irritation downward of the medial side of the tibia. It is named for Hermann Oppenheim. Other "BABINSKI-‐ LIKE RESPONSES" for the distinction student Abnormal reflex seen as extension of the big toe Bing's sign – multiple pinpricks on the dorsum of the foot Cornell's sign – scratching the dorsum of the foot Gonda's sign – flexing and suddenly releasing the 4th toe Moniz sign – forceful passive plantar flexion of the ankle Schaefer's sign – squeezing the Achilles tendon Stransky's sign – vigorously abducting and suddenly releasing the little toe Strümpell's sign – patient attempts to flex the knee against resistance Throckmorton's reflex – percussion over the metatarsopahalangeal joint of the big toe Abnormal reflex seen as flexion of toes Bekhterev-‐Mendel reflex – flexion of the 2nd to 5th toes on percussion of the dorsum of the foot Rossolimo's sign – exaggerated flexion of the toes induced by rapid percussion on the tips of the toes 43) on PULSES Dear Yin Ling, Today's bedside class reveal a remarkable lack of knowledge about the physical signs of valvular diseases. It is clear to me that the students know VERY little about the examination of the pulse. Pulse characteristics are often assessed at the radial and carotid arteries. However, all of the peripheral pulses should be examined. Palpation of both radial pulses simultaneously may pick up an Aortic dissection, and a radial and femoral pulse together will help establish the presence of coarctation of the aorta. The initial assessment of pulse rate, volume and character is usually obtained from the radial pulse. The pulse is lovingly felt with the your index and middle fingers on the palmar side of the wrist with your thumb on the dorsum of the wrist. Be sure to
explain to the patient what you are doing before attempting to palpate the femoral pulse! Radio-‐femoral delay is classically attributed to coarctation of the aorta, usually due to narrowing of the aorta just beyond the origin of the left subclavian branch. It is more often seen in young men. Sometimes a noticeably lower pulse volume in the femoral artery compared to radial artery is all that is appreciated rather than the classic delay in the femoral pulse. In older patients, radial femoral delay can potentially occur due to atherosclerosis and stiffness between the lower limbs and upper limbs arteries. Typically stiffer arteries lead to an increase in pulse wave velocity with more rapid propagation of the pulse wave. These patients also tend to have hypertension. Coarctation is sometimes diagnosed in older adults and should not be dismissed because of old age. Rate Ideally, Count the number of beats per minute. It is often convenient to count the number of beats over 15 seconds and then multiply by four. If the pulse is slow or irregular however, counting over a full 60 seconds will be more accurate. A normal resting heart rate ranges between 60 and 100 beats per minute. It is a normal for the pulse rate to vary slightly with respiration, particularly in the young, called sinus arrhythmia. This arrhythmia is related to differential filling of the left and right side of the heart and vagal tone with inspiration and expiration. Typically the heart rate increases slightly during inspiration, and decreases with expiration. As it is partly mediated by vagal tone, this effect, tends to decline with age. Rhythm The pulse is regular with sinus rhythm (apart from the caveat of sinus arrhythmia described above). A very rapid regular rhythm may indicate sinus, supraventricular or ventricular tachycardia. An irregular pulse can be regularly irregular (a recurring pattern such as bigeminy or type II heart block) or irregularly irregular (no clear pattern, such as atrial fibrillation). Volume The volume of the pulse is best assessed by palpating one of the larger arteries such as the carotid, brachial or femoral pulses. It is a subtle sign that requires experience over years for the examiner to recognize low and high volume pulses. A semi-‐ quantitative scale is used to describe pulse volume (increased, normal, reduced,
thready) Character This refers to an impression of the pulse waveform derived during palpation. Some abnormalities of pulse are described below. Anacrotic pulse This is seen in aortic stenosis, and refers to a pulse wave that is slow rising and generally flat volume associated with a low cardiac output and prolonged left ventricular ejection time. It suggests more severe aortic stenosis. Collapsing pulse This is a sign of aortic regurgitation, although it is also seen in patients with a hyperdynamic circulation and with a rigid arterial system. A stiff arterial system leads to an accentuated systolic peak in the peripheral pulses. The pulse has an early peak and then quickly falls away, giving it a tapping quality. The preferred method is to palpate the radial pulse with the palm and fingers wrapped around the flexor aspect of the wrist, and with the arm elevated upwards. This accentuates the tapping quality of the pulse. The collapsing pulse is also referred to as Corrigans or a water-‐hammer pulse, after a 19th century toy that was a vacuum tube containing water or mercury that was flipped creating a tapping or hammer sensation at the fingertips. When a collapsing pulse is detected look for the following signs; Duroziez sign: Seen in severe aortic regurgitation. Place the diaphragm of the stethoscope over the femoral artery and press downwards. Initially a systolic murmur will be heard. Gradually increase pressure over the artery-‐ a diastolic murmur will become evident also related to the flow reversal with profound aortic regurgitation. Now tilt the proximal edge of the stethoscope further downwards – if aortic regurgitation is present the systolic murmur is accentuated and the diastolic component is diminished. Now tilt the distal edge of the stethoscope downwards, the diastolic component will now be accentuated and the systolic reduced. This sign has a positive predictive value of close to 100% for aortic regurgitation, and can detect this lesion in some patients in whom it is not possible to hear the characteristic diastolic murmur on auscultation of the heart. Traubes sign: A “pistol shot” sound heard over the femoral artery with the aid of a
stethoscope. It is necessary to compress the femoral artery distal to the stethoscope head to produce the characteristic double tone sound. Hills sign: This is a nonspecific sign of aortic regurgitation-‐ it is also seen in other causes of a hyperdynamic circulation, such as thyrotoxicosis, beri-‐beri, or pregnancy. Check the blood pressures in the upper and lower limbs. If the pressure in the lower limbs exceeds that in the upper limbs by more than 20 mmHg then the sign is positive. Quinkes sign: Pulsatile blanching of the nail bed De Musset’s sign: Named after the famous French poet whose head nodded in time with his arterial pulsations due to his syphilis related aortic regurgitation. Pulsus paradoxus This is a misnomer. This is an exaggerated physiological phenomenon, rather than a paradox as the name implies. The volume of the pulse rises with expiration with the increase in stroke volume. and falls during inspiration. When it is present, it suggests either restricted left ventricular filling during inspiration (associated with a mild increases in pericardial pressure and increased right heart filling that shifts the interventricular septum towards the left ventricle to impair left sided filling) such as in pericardial tamponade, or exaggerated changes in intrathoracic pressure as in severe asthma.. Other causes of pulsus paradoxus include right ventricular infarction, large pulmonary embolus, and tense ascites or obesity. Pulsus alternans This abnormality describes a pulse that alternates between a larger and smaller volume on a beat to beat basis. This is a regular pulse and is seen in severe cardiac failure. Jerky pulse This is often seen in hypertrophic cardiomyopathy as the hypertrophied ventricle rapidly empties and then quickly drops its output as the outflow pathway is obstructed.-‐
44) on FUNCTIONAL MURMURS Dear Yin Ling, I tried very hard today to teach the kiddies the approach to cardiac examination. Most importantly I told them that the best thing they can do to improve their cardiac examination technique is to throw away the stethoscope. The majority of Cardiac problems can be diagnosed from peripheral signs without the stethoscope. The stethoscope confirms what we already know. Hence I get infuriated when the kids rush in to auscultate. NO NO NO! That's the final curtain call! Innocent systolic ejection murmurs are produced by turbulent flow through the proximal arteries at the time of ventricular ejection. The intensity of the murmur, as influenced by stroke volume or velocity of ejection, and proximity of the arteries to the chest wall determine whether the murmur is audible with the stethoscope. This ESM type murmur tends to peak in early to midsystole, usually ends before the second heart sound, and is best heard on the left side over the mitral or aortic valve or at the thoracic inlet. The murmur may be the result of turbulent flow into the pulmonary artery or aorta, or both. Functional systolic murmurs are produced by increased velocity of blood within the cardiovascular system and by extracardiac factors. Anemia, fever, hyperthyroidism, and tachycardia of any cause may produce functional murmurs. Decreased blood viscosity and increased velocity of blood flow produce turbulence. The functional murmur of anemia is usually of low intensity and high frequency and occurs during early systole to midsystole. Anemic murmurs are best heard over the mitral valve or aortic valve area. Functional murmurs may be audible when states of high cardiac output exist. The increased cardiac output is produced by both tachycardia and increased stroke volume. Some characteristics of Innocent/Functional Murmurs: 1. Systolic in nature 2. Usually short in duration 3. Usually soft 4. Usually heard along left sternal edge
5. Intensity varies with phases of respiration and posture -‐ usually louder when supine 6. Intensity louder with exercise, anxiety, fever Structural Lesions which may be missed: There are some structural lesions which give rise to murmurs closely resembling an innocent murmur. These differential diagnoses must be borne in mind and efforts made to exclude them clinically or with the help of investigations such as an electrocardiogram (ECG) or chest X-‐ray (CXR). Structural lesions which may be missed. Atrial Septal Defect: Ejection systolic murmur Fixed splitting of 2nd heart sound Mid-‐diastolic murmur at tricuspid area Right bundle branch block Pulmonary Valve Stenosis: Ejection systolic murmur ± ejection click, at 2nd intercostal space Murmur best heard during inspiration Post-‐stenotic dilalation of pulmonary artery MILD Aortic Valve Stenosis: Ejection systolic murmur at aortic area with ejection click LVH Mitral Valve Prolapse: Midsystolic murmur at mitral area with ejection click Hypertrophic Cardiomyopathy: Family history Systolic murmur at LSE radiating to aortic area Abnormal deep Q waves seen LVH
45) on VON RECKLINGHAUSEN Dear Yin Ling, I always have difficulty remembering the chromosomes involved "Neurofibromatosis Type I" = "von Recklinghausen has exactly 17 alphabets!" = Chromosome 17 "Neurofibromatosis Type II" = "Type 2 = 22" = Chromosome 22 46) on WILSON’S DISEASE Dear Yin Ling, To help you remember an uncommon condition commonly seen in exams..... Wilson's disease : ABCD A -‐ Asterixis B -‐ Basal ganglia degeneration C -‐ Copper accumulation with reduced Ceruloplasmin level, causing Cornea deposits (Kayser-‐Fleischer rings), Choreiform movements, psyChiatric abnormalities, liver Cirrhosis and treatment is with Chelation. D -‐ Dementia 47) on OCULOMOTOR NERVE My dear yin ling, Cranial nerves III, IV and VI are usually tested together. You instruct the patient to hold his head still and follow only with the eyes your finger or penlight that circumscribes a large "H" in front of the patient. Or you place your hand on his head to immobilise it for other than the abnormal medical person, any normal person will turn his head when asked to follow the finger! Since the oculomotor nerve controls most of the eye muscles, damage to this nerve is also known by the down n' out signs, because of the position of the affected eye.
Pupillary reflex The oculomotor nerve also controls the constriction of the pupils. This can be tested in two main ways. By moving a finger rapidly towards a person's face to induce accommodation, their pupils should constrict. Shining a light into their eyes from the side will make their pupils constrict. Do not shine from directly in front for any normal human will look at the light hence have accommodation reflex! Both pupils should constrict at the same time, independent of what eye the light is actually shone on. I tell my students a hundred times to Remember to approach from the side as the patient WILL focus on the penlight if you approach from his front and hence initiate accommodation and associated pupillary constriction, yet when I examine them, they will nonchalantly shine from the front. Peptic ulcer disease! Argyll-‐Robertson pupil (Aka "Prostitute's pupil" -‐ A prostitute Accommodates, but does not react ) Accommodation reflex present, Pupillary reflex absent The oculomotor nerve arises from the anterior aspect of midbrain. There are two nuclei for the oculomotor nerve: The oculomotor nucleus originates at the level of the superior colliculus. The muscles it controls are the ciliary muscle (affecting accommodation ), and all extraocular muscles except for the superior oblique muscle and the lateral rectus muscle. The Edinger-‐Westphal nucleus supplies parasympathetic fibres to the eye via the ciliary ganglion, and thus controls pupil constriction. When these fibres are damaged, the delicate sympathetic-‐ parasympathetic balance which maintains our pupillary size is upset and unopposed sympathetic drive causes a dilated pupil. 47) on STUMP APPENDICITES Dear Yin Ling, A male patient comes with fever, loss of appetite and RIF pain. He has past history of appendicectomy 3 years ago. On examination there is tenderness and mild guarding in the RIF.
What are your thoughts? Do you know appendicitis can re occur even after appendectomy ? Stump appendicitis, although rare, is a real entity that is often not considered during the evaluation of patients with right lower quadrant pain and a surgical history of appendectomy. The history of appendectomy may delay the diagnosis and management of this entity by misleading the physician into thinking that this patient could never have appendicitis again. However, the diagnosis of appendicitis should be considered in any patient with right lower quadrant pain, even if there is a history of appendectomy. Stump appendicitis is the re-‐inflammation of any residual appendiceal tissue after an appendectomy. Since the initial reports of stump appendicitis, it remains a rare condition; it occurs when there has been an incomplete appendectomy . Complete removal of the appendix is essential in preventing the occurrence of this condition. Many reports have suggested that stump appendicitis results from a stump that is left too long. It has been suggested that with the widespread use of laparoscopic technique, there might be an increase in the incidence of stump appendicitis, but stump appendicitis has been reported to occur after either laparoscopic or open appendectomy. Therefore, the relationship between laparoscopic appendectomy and stump appendicitis is not proven. One disadvantage of laparoscopic appendectomy is the inability to feel structures and judge pathology by palpation. Difficulty in retracting the long appendix may be responsible for the long appendiceal stump that may occur with laparoscopic appendectomy. The incidence of stump appendicitis is also probably underestimated and under-‐reported. 48) on Grave’s disease Dear Yin Ling, Grave's disease is defined by the three features of Eye involvement, Acropachy and occasionally Pre tibial myxodema on top of the Hyperthyroidism. Sometimes the eye involvement precedes the hyperthyroidism. They present as double vision, chemosis, protrusion, etc. To help you remember, pls recall
NO SPECS is the mnemonic used for the clinical progression of Graves' opthalmopathy. N: No signs or symptoms O: Only signs i.e. lid lag and lid retraction S: Soft tissue involvement (conjunctivitis, chemosis, and periorbital edema) P: Proptosis E: Extraocular muscles involved, commonly inferior rectus resulting in diplopia when looking up C: Corneal involvement (drying and ulceration due to the inability to close the eye lids) S: Sight loss.
49) on Renal Failure Dear Yin Ling, are you aware that the humble Starfruit is a killer!? Star fruit, belonging to the Oxalidaceae family, species Averrhoa carambola, is a popular fruit among Orientals. There have been reports of hiccup, confusion, and occasional fatal outcomes in uraemic patients after ingestion of star fruit.
An excitatory neurotoxin from star fruit has been implicated although the exact nature of this toxic substance has not been identified. Renal failure patients can have symptoms including hiccup, confusion, vomiting, impaired consciousness, muscle twitching and hyperkalaemia shortly after ingestion of star fruit. Symptoms of most patients can be resolved with dialysis or spontaneously. The close temporal relationship of ingestion of star fruit and onset of symptoms strongly suggests the existence of a causal relationship between the two. It is recommended that uraemic patients should totally abstain from star fruit due to these potentially fatal complications. 50) on Paralysis Dear Yin Ling, a patient presenting well and the after a while suddenly plops down in severe weakness and lethargy is dramatic and frightening. A condition that we suspect is Hypokalaemia. The hypokalemic paralysis include a group of disorders with differing etiologies but a common presentation. Familial hypokalemic paralysis (FHP) is a genetic channelopathy, with an autosomal dominant pattern of inheritance. Thankfully not common. Thyrotoxic hypokalemic periodic paralysis (THPP) is an acquired disorder that can present in a very similar manner to FHP when clinical features of hyperthyroidism are sub-‐clinical, as they commonly are. Treatment of hyperthyroidism prevents THPP, though the degree of hyperthyroidism does not predict the degree of paralysis. Patients often have no other symptoms of hyperthyroidism during attacks. Thankfully the patients I had seen all had obvious Grave's disease so it was not too difficult to diagnose. Thyrotoxic hypokalemic periodic paralysis is likely due to excessive thyroid-‐ hormone-‐induced adrenergic stimulation of the sodium-‐potassium (Na+-‐K+) pump, which drives potassium into cells. Potassium levels are normal between attacks, and there is no decrease in total body potassium. Attacks of paralysis are classically precipitated by an insulin surge after a high carbohydrate meal, or increased adrenergic activity with physical exertion.
However, other physiologic stressors such as sepsis, trauma, hypothermia, menses, and emotional stress are known triggers of THPP. Episodes are acute in onset and often occur in the nighttime or morning following a day of strenuous exercise. Patients may also describe a prodrome of muscle aches or cramps in the days preceding an acute episode. The patient may not have symptoms of overt hyperthyroidism, so thyroid function tests should be checked in all patients with hypokalemic paralysis. The EKG will demonstrate findings typical of hypokalemia. The hypokalemia of THPP affects the striated/skeletal muscles, not the nerves or the smooth muscle. Proximal muscles and those of the lower extremities are more severely affected, usually, but not always, in a symmetrical pattern; patients may have either hemiplegia or paraplegia. Muscles of respiration are typically spared, but cases of respiratory failure have been reported. Mental status and sensation are unaffected. In patients with THPP, hypokalemia is often exacerbated by associated hypophosphatemia and mild hypomagnesemia. Transport of phosphorus across cell membranes occurs with that of potassium. Thyrotoxic hypokalemic periodic paralysis is 20 to 40 times more common in hyperthyroid males than in hyperthyroid females, and occurs in up to 15% of hyperthyroid Asian males. All the patients I had seen were Males. Administering potassium during an attack can rapidly abort the episode. However, this should be done cautiously given the transient nature of the transcellular shift, as there is a risk of post-‐treatment hyperkalemia in up to 40% of patients. Cardiac arrest due to rebound hyperkalemia has been reported. Furthermore, spontaneous recovery of flaccid paralysis suggests that potassium can shift back out of the cell without supplementation. Nonselective beta-‐blockers such as propanolol is used to inhibit adrenergic stimulation of the Na+-‐K+ pump. (Remember that Hyperkaleamia is a contraindication for the use of propanolol!) With adequate suppression of adrenergic activity, as indicated by reduced heart rate, increases in serum potassium and rapid improvement of paralysis can be seen. This may eliminate the need for supplemental potassium. Patients with more severe or rapidly progressive paralysis, or with cardiac conduction abnormalities consistent with hypokalemia, should be treated with potassium. Prevention of acute episodes depends primarily on maintenance of a euthyroid state. Nonselective beta-‐blockers are also effective. Potassium supplements can be prescribed to be taken in case patients have an acute recurrent episode despite these measures.
However, because potassium levels are normal between attacks, there is no role for routine potassium supplementation or potassium-‐sparing diuretics. Management of THPP should include supportive care, with particular concern for respiratory status, and monitoring of serum electrolytes. Serial measurement of the FVC can give early warning that the patient may need respiratory support. Characteristics which would favor FHP over THPP include a family history of hypokalemic paralysis, Caucasian ethnicity, and female sex. Differentiation between FHP and THPP is critical because treatment differs. Familial hypokalemic paralysis requires a more vigorous potassium repletion, while THPP may be treated more conservatively, sometimes solely with observation or propranolol.
51) on Associations Dear Yin Ling, Brainstem answers now! When seeing nausea + tiredness+ hyperpigmentation =? addisonian crisis Weight loss + Amenorrhea + falling hair=? thyrotoxicosis Syncope + angina+dyspnoea = ? SAD is the symptoms of what? this is a classic triad!!! aortic stenosis weight loss + malaise + fever + pruritus=?? lymphoma
and the name of the fever???? pel ebstein fever Cant see, cant pee, cant climb a tree=?? reiter's disease abd pain + jaundice + fever=??? ascending cholangitis 5 causes of Fever, Chills and Rigours??? lobar pneumonia, abscess, pyelonephritis, malaria, ascending cholangitis others include Septicaemia, Influenza, Dengue Give me 5 causes of ESR >100 TB, Multiple myeloma, PMR, CTD, ADvance Malignancies esp with Paraneoplastic syndromes Septicaemia 52) on Peripheral Arterial Disease Dear Yin Ling, Significant proportions of patients do not have classical features of intermittent claudication and therefore PAD is an under-‐diagnosed condition. My students love to ask about calf pain and pain before how many "blocks", this as you know is utterly unreliable! Clinical examination is important to decide which patients should undergo further assessment, and palpation of the peripheral pulses is important. Any palpable pulse abnormality (absent or reduced femoral, popliteal, dorsalis pedis, or posterior tibial arteries) increases the likelihood of PAD and the absence of any palpable pulse abnormality decreases the likelihood of PAD.
However, assessing patency of the popliteal artery is not always possible by palpation. This is due to a combination of deep placement of the artery in the popliteal fossa and the presence of considerable quantity of fat both behind the artery and in the superficial tissues. One technique tested in OSCEs is using the flexion of the knees to facilitate relaxation of the gastrocnemius making it more accessible to palpation. In a patient with patent popliteal artery, the to and fro pulsatile movement of the foot (in conjunction with heart beat) will be observed when he sits in a high chair with legs crossed such that the popliteal fossa of the leg being examined lies over the knee of the opposite leg. The patient must sit on a high chair so that the popliteal fossa lies against the knee cap of the opposite leg. The top leg should be completely relaxed so the weight of the leg compresses the artery between the knee cap of the lower leg and the proximal part of the tibia This is called the "Cross leg test" or "Fuschig's test"
53) On Hypothyroidism and vague symptoms Dear yin ling, at every bedside class, I beg my students to always think of Hypothyroidism across a wide range of complaints from ACS to deafness to loss of memory to pruritus. Pls always think of it too in patients with muscle weakness or ENLARGED muscles!! Hypothyroid myopathy typically manifests as polymyositis-‐like myopathy with proximal muscle weakness and an increased creatine kinase level. However, it sometimes manifests as muscle enlargement (pseudohypertrophy); in adults, this
condition is called Hoffman syndrome. In children with hypothyroid disease (cretinism), a pattern of proximal weakness and diffuse muscle enlargement is also seen. Pls also note that hypothyroidism is thought to predispose individuals to rhabdomyolysis too. There is an inverse correlation between thyroid function and CK levels: in hypothyroid patients, CK levels were elevated, while in hyperthyroid patients, CK levels were lower than normal. After treatment to restore normal thyroid function, CK levels returned to normal. Three out of four patients with hyperthyroidism experienced muscle cramps during treatment to rapidly reduce thyroid function to normal levels. Serum creatinine kinase is decreased in thyrotoxicosis but increased in hypothyroidism. Prof Khalid has a publication on the subject in 1998 when he published about these subtle changes seen in subclinical hyper and hypothyroidism and hence questioned whether we should treat low TSH or high TSH when T4 or T3 are in the normal range. The Sign of Hertoghe or Queen Anne's sign is a thinning or loss of the outer third of the eyebrows, and is a sign of hypothyroidism.
Professor Khalid Kadir
53) on MEN Dear Yin Ling, Please do NOT proceed if you are under 21. I always had difficulty remembering MEN 1 and 2. Luckily I am not the one sitting for exams! This was until I was taught this!! There are 2 kinds of MEN in this world MEN Type 1, are straight guys, and they only think about Pussy, Pussy, Pussy! So they have malignancies of the Pancreatic Parathyroid Pituitary. MEN Type 2, are gay guys, and all they think about is Anus, Penis, and Testicles! So they have malignancies of the Adrenals Parathyroid Thyroid. And there you have it, both types of Multiple Endocrine Neoplasia... I mean, both types of MEN!
54) on Coarctation Dear Yin Ling, What is Dock's sign? Bilateral rib notching seen in CXR in Coarctation of the Aorta is known as Dock's sign, corresponding to the collateral circulation of the internal mammary arteries typically at ribs 3-‐8. Inferior Rib Notching is usually due to enlargement of the neurovascular bundle. Consider the following main causes: Coarctation of the Aorta Fallot's tetralogy -‐ unilateral left following Blalock-‐Taussig shunt (left subclavian artery anastamosed to left pulmonary artery -‐ collateral circulation via ribs to supply arm) Neurofibromatosis (more classically wavy 'ribbon ribs') Longstanding SVC obstruction (venous collaterals) Coarctation of the Aorta is classified into 2 types Localised (Adult) Most common type. Short narrowing close to ligamentum arteriosum. Cardiac anomalies uncommon. Tubular hypoplasia (Infantile). Long segment stenosis. Cardiac anomalies common.
55) on Pulmonary Embolism Dear Yin Ling, undiagnosed PE has a hospital mortality rate as high as 30%, which falls to about 8% if PE is diagnosed and treated appropriately The diagnosis of PE remains one of the most difficult problems confronting clinicians. PE is considered in the differential diagnosis of many clinical presentations, including chest pain, hemoptysis, and dyspnea. Yet less than 35% of patients suspected of having PE actually have PE In patients with Pulmonary embolism, pleuritic chest pain and haemoptysis indicates that Pulmonary Infarction had occurred. Only about 1 in 10 patients with Pulmonary embolism develop into pulmonary infarction! Sudden onset of dyspnoea, vague chest pain, light headedness are the most common symptoms of PE. The majority of patients have no signs other than tachypnoea and tachycardia, while extensive embolism will result in cyanosis, increased JVP, hypotension. Pulmonary infarction will result in haemoptysis, Pleural rub, FEVER, dullness and crepts over the infarcted area and sometimes pleural effusion. Ple remember that recurrent small PE is a cause of PUO. Hemodynamic decompensation occurs not only because of physical obstruction of blood flow but also because of the release of humoral factors, such as serotonin from platelets, thrombin from plasma, and histamine from tissue. Acute PE increases pulmonary vascular resistance, partly attributable to hypoxic vasoconstriction. In patients without prior cardiopulmonary disease, the mean pulmonary artery pressure can double to approximately 40 mm Hg. Pls note that No ABG data had sufficient negative predictive value. A normal ABG does NOT exclude PE. Hypoxaemia seems to be a reliable sign of pulmonary embolism, a pO2 of under 50 mm Hg was always associated with a severe embolism with amputation of over 40% of the pulmonary vascular bed. The failure of
supplemental oxygen to correct arterial hypoxemia accompanying acute PE often reflects the existence of right to left shunting of venous blood through the heart, the lungs, or both. Respiratory alkalosis is commonly seen There is Right-‐to-‐left shunting: no ventilation and venous blood enters systemic circulation. Increased anatomic dead space: breathed gas does not enter gas exchange units of the lung A neg D Dimer serves only to exclude and a positive result cannot confirm. Wells' Two-‐level PE Score helps in decision making
Hampton’s hump long arrow: the wedge-‐shaped opacity at the peripheral left lung field Palla’s sign short arrow: enlargement of the Right descending pulmonary artery
Westermark’s sign: the area of hypoperfusion distal to the right pulmonary vasculature. This represents a probable pulmonary embolism. 56) on Red Meat Dear Yin Ling, "The gouty arthritis patient was advised NOT to eat red meat" 'Why?' I ask? 'WHY???' Why some meats — not just pork or chicken — are lighter or darker is a fairly complicated subject. Several factors contribute to the colour of meat. Why is your stirred fried horr funn's beef dark in colour ie red meat?
Haemoglobin, is absorbed in muscle, contributes a bit of red colour. Muscles that are heavily used may not be able to get enough oxygen from the blood, and must resort to oxygen stored in myoglobin molecules. Both haemoglobin and myoglobin are red when carrying oxygen. Depending on how much use the muscle sees, there is more need of the oxygen stored in myoglobin, and will be darker as a result. Turkeys for example, which stand around a lot and hardly ever fly, have dark leg meat but breasts that are white. Game animals, which tend to use all their muscles, are essentially all dark meat, while domesticated animals generally have a mix of both light and dark. In terms of cooking, dark meat generally has more flavour, but, because those muscles were more actively exercised, tends to be tougher. Lighter meats tend to be more tender but have less flavour. Now you know why some meats are tender and some tough. Diets which are high in purines and high in protein have long been incriminated of causing an increased risk of gout. High uric acid levels associated with gout derive largely from foods rich in protein and purine, which produce uric acid as a waste product People who consumed the highest amount of meat were 40 percent more likely to have gout than those who ate the least amount of meat. People who ate the most seafood were 50 percent more likely to have gout. Obesity can be linked to high uric acid levels in the blood. People who are overweight should go on a reasonable weight-‐loss program. Fasting or severe dieting can actually raise uric acid levels and cause gout to worsen. Usually people can eat what they like within limits. People who have kidney stones due to uric acid, gouty tophi, chronic tophaceous gout may need to actually eliminate purine-‐rich foods from their diet because those foods can raise their uric acid level. Consuming coffee and tea is not a problem but alcohol can raise uric acid levels and provoke an episode of gout. Drinking at least 10-‐12 eight-‐ounce glasses of non-‐ alcoholic fluids every day is recommended, especially for people with kidney stones.
57) On Prednisolone Dear Yin Ling, Prednisolone can have unique side effects well known to us all. Among the most memorable ones are Pancreatitis Avascular necrosis of the head of the femur Posterior sub capsular cataract Extensive acne Intracranial HPT Papillodema Psychosis Glaucoma I remember these well because Prof Florence Wang taught me this. She was running the Lupus clinic in UH and used a lot of prednisolone. 58) On FT3 Dear Yin Ling, What is this T3 that we see in our thyroid function tests? How do we interprete it? When is it useful? TRI-‐IODOTHYRONINE (T3) There are two assays available, one measures total T3 and the other free T3. The total T3 comprises of both protein bound and free T3. The free component is the active form and comprises a mere 0.3% of total circulating T3. T3 is the biologically active thyroid hormone, possessing 5 times the metabolic power of T4. In man some 80% of T3 is produced from T4 by conversion in liver and kidney. Therefore little is produced in the thyroid itself. The conversion of T4 to T3 can depend on a number of situations such as chronic illness or surgical stress which cause a fall in T4 to T3 conversion (called low T3
syndrome). Hence FT4 may be normal and the patient is hypothyroid! Starvation also alters T4 to T3 conversion with a fall in T3 as the body tries to reduce its metabolism to conserve energy. This is survival adaptation. Measurement of fT3 in patients with suspected hyperthyroidism is rarely indicated. This is reserved for situations where hyperthyroidism is suspected clinically and TSH is suppressed, but the fT4 is not elevated. fT3 if elevated tells us that T3 thyrotoxicosis is present. Measurement of fT3 is not indicated in hypothyroidism. In hyperthyroidism, both thyroxine T4 and T3 levels (total and free) are usually elevated. Treatment and monitoring can be done with FT4 but if FT4 is normalised with treatment and patients still appear hyperthyroid then FT3 should be measured. Pls note that the suppressed TSH takes time to recover and hence is not helpful initially. FT3 levels may be required to evaluate clinically euthyroid patients who have an altered distribution of binding proteins (eg, pregnancy, dysalbuminemia). Btw pls do not diagnose subclinical thyroid dysfunction unless you are sure that the following is fulfilled. The following five criteria define endogenous subclinical thyroid dysfunction: a. TSH increased above, or decreased below designated limits b. Normal free T4 concentration and free T3 c. The abnormality is not due to medication d. There is no concurrent critical illness or pituitary dysfunction. e. A sustained abnormality is demonstrated over 3-‐6 months. Therefore in summary Measurement of serum T3 is indicated, as follows: a. In suspected hyperthyroidism with suppressed TSH and normal serum T4, to identify T3-‐thyrotoxicosis and distinguish this entity from subclinical thyrotoxicosis. b. During antithyroid drug therapy to identify persistent T3 excess, despite normal or low serum T4 values. c. For diagnosis of amiodarone-‐induced hyperthyroidism, which should not be based
on T4 excess alone because of the frequency of euthyroid hyperthyroxinemia during amiodarone treatment. d. To assess the extent of T3 excess in individuals treated with thyroid extracts of animal origin, our sinsehs uae monkey thyroid dried and grounded! And to assess a potentially damaging hormone excess that is not reflected by the level of T4. e. To identify T3-‐predominant thyrotoxicosis, an entity that is less likely to achieve remission. f. To detect early recurrence of hyperthyroidism after cessation of antithyroid drug therapy. h. To establish the extent of T3 excess during high-‐dose replacement or suppressive therapy with T4, or after an accidental or intentional T4 overdose. Low serum T3 concentrations have little specificity or sensitivity for the diagnosis of hypothyroidism. Many patients with nonthyroidal illness have low values, and the serum T3 concentration can remain in the reference range until hypothyroidism is severe.
59) on Calcifications in CXR Dear Yin Ling, This CXR shows innumerable small, punctate calcifications throughout both lungs. No difficulty for you. What are the differential diagnosis?
Calcification in a pulmonary nodule (PN) on imaging indicates a high probability that the lesion is benign. But not all calcified PN are benign and the differential considerations include a primary central lung carcinoid, metastasis and a primary bronchogenic carcinoma. Radiological demonstration of calcification in lung cancers is uncommon but when encountered may lead to misdiagnosis. Amorphous, punctate, and reticular patterns of calcification have been described in lung cancer. Malignant tumors may engulf a pre-‐existing granuloma.
The prevalence of calcified lung cancers identified on conventional chest radiographs is said to be 1%. Malignant nodules may mimic the appearances of benign calcified granulomas; typical examples are metastases from osteogenic sarcoma or chondrosarcoma. Differential diagnosis of diffusely distributed small calcified nodules includes infections, lung metastases, chronic pulmonary hemorrhage, pneumoconiosis, deposition diseases and idiopathic disorders such as pulmonary alveolar microlithiasis. Post Chicken pox pneumonia Chicken pox pneumonia may cause tiny widespread micronodular calcification with nodules 1-‐3 mm in diameter as a late sequela. There is no associated calcification of mediastinal lymph nodes. TB Histoplasmosis Dystrophic calcification follows caseation, necrosis or fibrosis. Calcified nodules following infections are well defined and often measure 2-‐5 mm in diameter. Such nodules often follow healed disseminated histoplasmosis and rarely may follow healed miliary tuberculosis. When secondary to tuberculosis or histoplasmosis, there is generally associated calcified hilar or mediastinal lymph nodes. Occupational Lung disease Patients with silicosis and coal miner's pneumoconiosis often develop small (
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