Nephrology MCQ.pdf

Nephrology The following are true of tubular function A 50% of sodium has been reabsorbed by the start of the distal convoluted tubule

(False)

B creatinine is secreted into the proximal tubule

(True)

C aldosterone acts predominantly on cells in the collecting duct

(False)

D distal tubular lesions lead to amino aciduria

(False)

E phosphate resorption is controlled by parathyroid hormone

(True)

Comments: a->50%, b-that's why it isn't a perfect estimate of GFR, c-distal convoluted tubule, d-PTH causes excretion

The following require reduced dosage in severe renal impairment: A Ciprofloxacin

(True)

B Rifabutin

(True)

C Erythromycin

(True)

D Nitrofurantoin

(True)

E Vancomycin

(True)

Comments: The use of drugs in patients with reduced renal function gives rise to problems for several reasons:

• • • •

Failure to excrete a drug or its metabolites may produce toxicity. Sensitivity to some drugs is increased even if elimination is unimpaired. Many side effects are tolerated poorly by patients in renal failure. Some drugs cease to be effective when renal function is reduced. Many of these problems can be avoided by reducing the dose or by using alternative drugs.

Appendix 3 of the British National Formulary has a huge list of such adjustments to dosages, and all the above drugs are included on it. Copyright © 2002 Dr Colin Melville

In chronic renal failure there is A a correlation between falling GFR and rising parathyroid activity

(True)

B a failure to hydroxylate 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol

(True)

C no evidence that raised blood urea levels contribute to symptoms

(False)

D shortened red cell survival

(True)

E an increased incidence of gout

(False)

Comments: a - secondary and tertiary hyperparathyroidism b - 25 hydroxylation of Vitamin D is in the liver 1 hydroxylation in the kidney c - ureamia may cause coma, convulsions, flapping tremor, myoclonus, pericarditis ... d - red cell survival is reduced, red cell production reduced - erythropoietin is produced in the kidney e - gout is suprisingly rare despite the presence of hyperuricaemia

The following are recognised presentations of AR polycystic kidney disease: A Berry aneurysm

(False)

B Nephrogenic diabetes insipidus

(True)

C Bilateral flank masses at birth

(True)

D Presentation with Nephrotic Syndrome

(False)

E Potter's Syndrome

(True)

Comments: Cysts may occur in the kidney and liver. Absent antenatal urine production results in oligohydramnios and Potter syndrome. Occasionally they can present with renal failure or nephrogenic DI. Copyright © 2002 Dr Colin Melville

Inability to lower the urine pH below 5.2 is a characteristic feature of A cranial diabetes insipidus

(False)

B chronic lithium therapy

(True)

C renal tubular acidosis

(True)

D respiratory failure

(False)

E chronic renal failure

(False)

Comments: b-causes type 1 renal tubular acidosis and can cause a nephrogenic DI, c-diagnostic test, e-usually can acidify urine (acidosis is from bicarbonate leak?)

Acidosis may result in A potassium retention

(True)

B a rise in plasma chloride

(True)

C a low pCO2

(True)

D peripheral vasodilation

(True)

E tetany

(False)

Comments: An acidosis is associated with potassium retention and rise in chloride with maintanence of the anion gap. Peripheral vasodilatation occurs in an effort to improve oxygenation of metabolising tissue. Alkalosis is associated with tetany and reduction of ionised calcium concentration. In an effort to correct the acidosis, respiration increases with consequent reduced pCO2.

In Nephrotic Syndrome: A The prognosis is poorer in children than in adults.

(False)

B The patients are more than usually susceptible to bacterial infection.

(True)

C The plasma level of IgG may be diminished.

(True)

D Highly selective proteinuria increases the likelihood of complete recovery.

(True)

E Spontaneous remissions occur only with the 'minimal change' lesion.

(False)

Comments: Nephrotic Syndrome is characterised by proteinuria, hypoproteinaemia, oedema, and hyperlipidaemia. Minimal change disease is found in 85%, mesangial proliferation in 5%, and focal sclerosis in 10%. Increased glomerular capillary wall permeability results in proteinuria, and this is related to the loss of negatively charged glycoproteins from within the capillary wall. Loss is predominantly of albumin. The increased susceptibility to infection may be due to decreased immunoglobulin levels, oedema fluid acting as a culture medium, protein deficiency, decreased bactericidal activity of leukocytes, steroid therapy, decreased splenic profusion due to hypovolaemia, urinary loss of properdin factor B (which opsonizes certain bacteria). Spontaneous peritonitis, septicaemia, pneumonia, cellulitis and urinary tract infections are seen. Streptococcus pneumoniae and gram negative bacteria are most important. Steroid therapy may mask fever and physical findings. In minimal change disease, the proteinuria is highly selective, and 95% respond to steroids. Most children with steroid responsive nephrosis (either minimal change or from other causes) have repeated relapses until the disease resolves itself towards the age of 20 years.

Wilm's Tumour A Is the commonest solid tumour of childhood

(False)

B Can be cured in 80 - 90% of cases

(True)

C Occurs bilaterally in around 10% of cases

(True)

D Is associated with hemihypertrophy

(True)

E Is familial in approximately 5% of cases

(False)

Comments: Leukaemias are the commonest cancers in childhood, followed by brain tumours and lymphomas. Neuroblastoma and Wilm's are equal fourth commonest. Wilm's tumour accounts for most childhood renal neoplasms, and is associated with congenital anomalies such as genitourinary abnormalities (4%), hemihypertrophy (3%), and sporadic aniridia (1%). Deletions on chromosome 11 account for 33% of cases (bilateral cases occur in 10%). There are 3 associated syndromes: · WAGR Syndrome (Wilm's tumour, aniridia, genitourinary malformations, mental retardation). · Denys-Drash Syndrome (Wilm's tumour, nephropathy, genital abnormalities). · Beckwith-Weidemann Syndrome. Prognosis is generally excellent, with stage 1 disease having a 97% survival, stage 2 disease a 92% survival and stage 3

disease an 87% survival. Stage 4 disease has a 73% survival. Copyright © 2002 Dr Colin Melville

These features are associated with renal osteodystrophy A increased gut absorption of calcium

(False)

B distal myopathy

(False)

C hypophosphataemia

(False)

D raised serum alkaline phosphatase

(True)

E skeletal features of osteomalacia and hyperparathyroidism

(True)

Comments: There is reduced gut absorption of Calcium. A proximal myopathy associated with hypovitaminosis D is typical and this contributes to hypocalcaemia with hyperphosphataemia. Consequently alkaline phosphatase is elevated reflecting increased bone demineralisation and secondary hyperPTH ensues.

Nephrogenic diabetes insipidus is commonly associated with: A Recurrent fevers

(True)

B Craving for table salt

(False)

C Abnormal growth

(True)

D Urinary osmolality of 200 MOsmols/kg H20 or less

(True)

E XY Karyotype

(True)

Comments: Clinical manifestations of nephrogenic DI include thirst, dehydration and hyperthermia. Patients crave water and ice cold drinks rather than salt. Inadequate caloric ingestion associated with incessant water intake can cause growth retardation and repeated bouts of hypernatraemia can cause mental impairment. Urine osmolarity of less than 200 mOsmols/kg H20, hypernatraemia and urine specific gravity of 1.005 or less are characteristic. Familial nephrogenic DI is commonly X linked and males present more often.

Haematuria in children may be due to: A vitamin A deficiency

(False)

B nephroblastoma

(True)

C meatal ulcer

(True)

D measles

(False)

E schistosomiasis

(True)

Comments: 1. this causes keratomalacia and xerophthalmia 2. Wilm's tumour, haematuria usually a late feature. 3. due to bleeding from the meatal ulcer 5. due to bladder involvement in Schistosoma haematobium infection

A raised serum bicarbonate level is consistent with A hypokalaemia

(True)

B pyloric stenosis

(True)

C diabetic ketoacidosis

(False)

D chronic lung disease

(True)

E chronic renal failure

(False)

Comments: a) Metabolic alkalosis usually accompanies hypokalaemia probably due to a shift of hydrogen ions from the extracellular to the intracellulr space. b) loss of acid from persistent vomiting c) bicarbonate low d) respiratory failure with CO2 retention and high bicarbonate e) mild acidosis

Hypernatraemic dehydration is commonly associated with the following: A Cholera

(False)

B Pyloric stenosis

(False)

C Inappropriate ADH secretion

(False)

D Diabetes insipidus

(True)

E Diabetes mellitus

(False)

Comments: Cholera results in excessive water and sodium losses and hence hyponatraemia. Pyloric stenosis typically results in hypokalaemic, hypochloraemic, metabolic alkalosis and not cause hypernatraemia. Inappropriate ADH secretion causes hyponatraemia. In Diabetes insipidus failure to concentrate urine results in hypernatraemic dehydration with hyperosmolarity. Poorly controlled diabetes results in osmotic diuresis and renal sodium loss.

Hyponatraemia can occur in: A Congenital adrenal hyperplasia

(True)

B Gastroenteritis

(True)

C Diabetes insipidus

(False)

D Diabetes mellitus

(True)

E Severe pneumonia

(True)

Comments: Hyponatraemia occurs in congenital adrenal hyperplasia due to failure to synthesise cortisol and mineralocorticoid. Gastroenteritis may cause loss of sodium and water through and hence hyponatraemic dehydration. Diabetes insipidus causes hypernatraemia. Diabetes mellitus may cause osmotic diuresis and associated tubular sodium loss. Pneumonia may cause inappropriate ADH secretion and hyponatraemia results.

Alpha-1 antitrypsin deficiency is associated with: A panniculitis

(True)

B neonatal jaundice

(True)

C glomerulonephritis

(True)

D bronchiectasis

(True)

E cANCA

(True)

Comments: a) Panniculitis is nodular fat necrosis. The nodules vary in size and are tender lasting 1 - 8 weeks. There may be systemic upset. Other causes of panniculitis with systemic disease include SLE, scleroderma, lymphoma, histiocytosis and pancreatic disease. b) 80% of PiZZ genotypes show biochemical signs of hepatocellular damage in the first year of life d) and emphysema of course (Note: Pseudomonus aeruginosa makes a protease which cleaves alpha-1 antitrypsin thereby producing lung damage). e) cANCA may be seen in PiMZ and PiZZ genotypes.

In mumps: A The incubation period is usually 21 days.

(True)

B Orchitis is typically bilateral.

(False)

C Aseptic meningitis is a complication.

(True)

D Amylase may be increased despite no evidence of pancreatitis clinically.

(True)

E Sublingual swelling may occur.

(True)

Comments: Paramyxovirus infect the salivary glands, especially the parotids. It is spread by direct contact, saliva, droplets, and urine. 85% of patients are 10% clinically or ? up to 65%. Orchitis affects 25% of adolescents. Bilaterally in 30%, only Æ fertility, not sterility. It rarely causes oophoritis, pancreatitis, nephritis, thyroiditis, myocarditis, mastitis, deafness (but important), ALSO, eye, joints and low platelets (3TP). Copyright © 2002 Dr Colin Melville

The following regarding Atrial Natriuretic Peptide are correct A It is secreted in response to right atrial distension

(True)

B It inhibits aldosterone release

(True)

C It is a direct inotrope

(False)

D It is a direct vasodilator

(True)

E It is inactivated by endopeptidase

(True)

Comments: ANP is a 28 aa peptide that is synthesised and released by atrial myocytes in response to distension, angiotensin II and endothelin. It causes salt and hence water losses, is a vasodilator (through possible direct and indirect mechanisms) and inhibits aldosterone release. Such actions reduce blood volume and cardiac output. ANP is degraded by neutral endopeptidase.