8.2 Medicine_Tropical Infectious Diseases,Typhoid, Malaria_2014A

Let’s imagine it happened

Getting Sick in the Tropics  (Tropical IDs) Part 2: Typhoid Fever & Malaria Dr. Rosario OUTLINE: Part 1: Overview A. B. Dengue A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T. U.

Part 2: Tropical infectious diseases III. Typhoid fever 10 leading causes of morbidity A. Etiologic agents B. Enteric fever Dengue virus C. Complications and Transmission of dengue virus by consequences aedes aegypti D. Laboratory tests Dengue infections E. Antibiotic therapy Pathophysiology F. Case course Course of illness G. Prevention Old WHO dengue classification Malaria Dengue case classification and A. Etiologic agents levels of severity B. Transmission cycle Diagnosis C. Laboratory tests Tourniquet test D. Clinical features Step-wise approach to E. Major signs of severe management of dengue malaria Group A F. Other signs of severe Home care for dengue malaria Admission criteria G. Drugs for susceptible Group B plasmodium Group C H. Drugs for MDR Effects of supportive treatments I. Drugs for severe or for DHF or DSS in children complicated P. Group C: emergency treatment falciparum malaria Summary of blood transfusion J. Primaquine treatment K. Other issues Discharge criteria Prognosis Part 3: Leptospirosis Prevention

TYPHOID FEVER Case # 2:  25 year old, female, government employee  Intermittent fever and chills for seven days, relieved temporarily by paracetamol  Headache, myalgia, body malaise and vague abdominal pain  History of diarrhea x 1 day  She denies travel to remote area  Unremarkable PE except for T= 38.6oC o

Fever with normal heart rate  relative bradycardia: seen in patients with typhoid fever and legionella infection) [2013B]

Case # 2: Issues  Absence of focal findings o Non-specific signs and symptoms o Clues in the clinical data: historical/ suggestive physical findings  Possible etiologic agent o Standard diagnostic procedure  Empiric therapy o Drug of choice  Resistance patterns ETIOLOGIC AGENT [Harrison’s] SALMONELLA  S. typhi or S. paratyphi serotypes A, B, C  Gram-negative, non-spore forming, facultative bacilli  Growth restricted to human hosts

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anaerobic

 Mode of transmission: ingestion of organisms in contaminated food or water d/t fecal contamination by ill or asymptomatic chronic carriers.  Pathogenesis: o Penetrates and targets small intestine; phagocytosed by macrophages o Spread to other organs via lymphatics and colonize RES tissues o S/Sx result from cytokine secretion in response to bacterial products after critical no. of organisms have replicated  S. paratyphi A causes milder disease than S. typhi  Occurrence of multidrug resistant (MDR) strains of S. typhi o Contain plasmids encoding resistance to chloramphenicol, ampicillin, trimethoprim o Abx long used to treat typhoid fever ENTERIC (TYPHOID) FEVER: MANIFESTATIONS  Systemic disease characterized by fever and abdominal pain and caused by dissemination of S. typhi or S. paratyphi.  Incubation period: 3-21 days (ave. 10-14 days)  Most prominent sx: prolonged fever (38.8-40.5 oC) if untreated  Early findings: rash, hepatosplenomegaly, epistaxis, relative bradycardia at peak of high fever  “Rose spots” faint salmon colored, blanching, maculopapular rash located primarily on the trunk and chest; evident at end of 1st week; resolves after 2-5 days

COMPLICATIONS AND CONSEQUENCES [Harrisons] Development of severe disease depends on host factors (immunosuppression, antacid therapy, previous exposure, vaccination), strain virulence and inoculum, and choice of antibiotic therapy.

 Intestinal hemorrhage o Severe GI bleeding  Intestinal perforation  Peritonitis  Kidney failure  Orchitis  Chronic carrier states  Myocarditis  Neurologic manifestations o Encephalitis (Psychosis) o Meningitis, Guillain-Barré syndrome, neuritis, and neuropsychiatric symptoms (described as "muttering delirium" or "coma vigil"), with picking at bedclothes or imaginary objects. [Harrisons]

LABORATORY TESTS    

Case 2 Lab Results: CBC: Hgb= 14.3 Hct= 0.47 RBC = 3.85 WBC = 6.5 N=70 L=26 E=1 M=3 Platelet count= 190,000 Urinalysis (-) Typhidot: IgM (-); IgG (+)

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 Three-day courses are also effective, particularly in epidemic containment  The treatment for quinolone resistant typhoid fever has not been determined. Azithromycin, the third generation cephalosporins, 10-14 day course of highdose fluoroquinolones, is effective. Combination of these is also being evaluated.  3 First-line Agents in Philippines: 1. Chloramphenicol 2. Amoxicillin/ Ampicillin 3. Co-trimoxazole

Question: What laboratory examination would be the most helpful test before starting any antibiotic? A. Complete blood count B. Urinalysis C. Immunochromatographic test (Typhi Dot) D. Blood culture and sensitivity [2013B]  Immunochromatographic Test (Typhi Dot) o Antibody test; tells previous exposure; it may not truly tell if there is a disease  Blood culture and sensitivity o Isolates organisms; best tool

[Harrisons]  Prompt administration of appropriated antibiotic therapy prevents severe complications and results in a case fatality rate of 30 min after generalized convulsion Hematocrit 50 mmol/ L (>3 mg/dl) Rectal Temperature >40°C

Contraindications:  Patients with G6PD deficiency  hemolysis  Not used for active disease

[Harrisons 18th ed]

OTHER ISSUES 1. 2.

[Harrisons 18th ed]

Jaundice Hyperpyrexia

DRUGS FOR SUSCEPTIBLE PLASMODIUM SP. Question: Which of the following anti-microbials would you give? A. Chloroquine + Sulfadoxine/Pyrimethamine B. Quinine + Doxycycline C. Artemether + Lumefantrine D. Primaquine  Uncomplicated malaria o Susceptible P. Falciparum  Chloroquine  can

cause

Management of Complications [2013B]  Regarding hypoglycemia, quinine can induce insulin release which can aggravate hypoglycaemia  Pulmonary edema: unknown reason why patients develop this, so ventilatory support should be given  Acidosis: give bicarbonate  Renal failure: require dialysis

tinnitus

[2013B]

o

3.

Management of Complications Adverse events related to drug interventions and interactions Prevention

Prevention  Chemoprophylaxis  Use mosquito nets. It is more effective if the mosquito

 Sulfadoxine/pyrimethamine Other susceptible Plasmodium sp.  Chloroquine

 One criteria that you have to consider in choosing drugs is resistance of species  In the Philippines, more than 60% is resistant especially in Palawan

DRUGS FOR MULTI-DRUG RESISTANCE PLASMODIUM FALCIPARUM MALARIA  Artemether-lumefantrine (Co-Artem) 1.5/9 mg/kg BID with food for 3 days (or artesunate 4mg/kg qd) PLUS  Mefloquine 15-25 mg base/kg for 3 days

DRUGS FOR SEVERE OR COMPLICATED P. FALCIPARUM MALARIA  Drug/s of choice: IV quinine (or quinidine) + Doxycycline or clindamycin  Alternative: Artemisinin derivatives

PRIMAQUINE  For radical cure  Used as gametocidal drug for P. Falciparum malaria  Used as a hypnozoiticidal drug for P. Vivax or P. Ovale infection to prevent relapse [2013B]

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net is treated with insecticide Use long sleeves and pants Use repellants and screens on doors and windows Clear hanging branches of trees along the streams Have your blood examined if you have the signs and symptoms of malaria  Follow the advice of health workers on how to take antimalaria drugs.  Primary area where Malaria is endemic- PALAWAN  Avoidance of exposure to mosquitoes at their peak feeding times (usually dusk to dawn) as well as the use of insect repellents containing 10–35% DEET

   

1. 2. 3.

What Plasmodium species causes relapse in malaria? Which among the dengue serotype causes the more severe disease? What is the drug of choice for the treatment of typhoid fever in the Philippines?

Answers: (1) P. vivax & P.ovale; (2) Serotype 2; (3) Chloramphenicol

QUIZ:

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