Tropical Diseases

Question 1

Diagnosis of dengue (without warning signs)

Answer 1

presumptive diagnosis:
- residence or travel to an endemic area PLUS
- fever PLUS
any 2 of the following:
- N/V
- Rash
- Headache, eye pain, muscle ache, joint pain
- Leukopenia
- Positive tourniquet test

Question 2

Warning signs of severe infection

Answer 2

7

1. severe abdominal pain
2. persistent vomitting
3. clinical fluid accumulation (ascites, pleural effusion)
4. mucosal bleeding
5. lethargy, restlessness
6. hepatomegaly >2cm/ <3finger breath
7. increase in hct >20% and plt drop >50%

Question 3

What is severe dengue

Answer 3

dengue with at least 1 of the following

1. severe plasma leakage:
   - shock
   - fluid accumulation with resp distress
2. severe bleeding
3. severe organ involvement
   - Liver: transaminitis AST/ALT>1000
   - CNS: impaired consciousness, encephalopathy
   - Heart: myocarditis

Question 4

What are the 5 species causing malaria

• which is most common
• which is most mortality
• common in Malaysia

Answer 4

P. vivax
P. ovale
P. falciparum
P. malariae
P. knowlesi
most common: P vivax and P falciparum
most severe: P falciparum
Malaysia: P knowlesi

Question 5

Modes of transmission of malaria

Answer 5

• vector: bite of infected female Anopheles mosquito (evening)
• congenital (mother-fetus)
• blood transfusion, needle, transplants

Question 6

Lab results suggestive of malaria

Answer 6

anemia

thrombocytopenia

Question 7

Complications of malaria

Answer 7

• Cerebral malaria (100% fatal if not treated)
• Renal failure
• ARDS/ pulmonary edema
• Haem: DIVC and bleeding, hemolytic anemia
• Hypoglycemia
• Splenic rupture
• Gastroenteritis

Question 8

How to test for malaria

Answer 8

Microscopy (venous blood or finger prick) - Gold standard

• Giemsa stained (3 samples)
• Thick smear: more sensitive
• Thin smear: speciation

Rapid Diagnostic tests

Others:

• fluorescent
• PCR
• HRP2 antigen

Question 9

how to treat P falciparum

Answer 9

Artemisinin combination therapy (ACT)

• artesunate VI
• PLUS doxycycline or mefloquine

others: quinine plus doxycycline, mefloquine, malarone

Question 10

how to treat P vivax

Answer 10

chloroquine stat
primaquine (check G6PD levels first) for terminal eradication
- else risk of relapse

Question 11

how to mgx malaria in the wards

Answer 11

supportive care

• admit ICU if v ill
• meticulous fluid management
• monitor blood sugar (reduced food intake, increased sugar consumption due to fever and by parasites, quinine stimulated hyperinsulinemia)

kiv baseline ecg if using quinine (can cause arrhythmias)

Exchange transfusion - no longer recommended

Question 12

What to give for malaria prophylaxis

• Duration
• Side effects

Answer 12

3 options

1. Mefloquine
   - weekly
   - 1w before travel until 4w after travel
   - SE: dizziness, sleep disturbances, psych effects
   - CI: depression, arrhythmias, seizures, beta blockers
2. Doxycycline PO OM
   - 1 d before travel till 28 d after travel
   - CI: pregnancy, children <8
   - SE: sun sensitivity, drug interaction with OCP, yeast infection
3. Malarone PO
   - 1 d before travel till 7 days after

Question 13

What are the symptoms of typhoid

Answer 13

1w: high fever>40, chills, fatigue, relative bradycardia, constipation (diarrhoea rare)
2w: rose spots, diarrhoea, ab pain
3w/4w: intestinal bleeding, perforation, hepatosplenomegaly, peritonitis

other cx: myocarditis, encephalitis, renal failure, abscess in liver, spleen and bones

Question 14

how to tx and follow up typhoid

Answer 14

TX food handlers, HCW, DCW
Depends on whether typhoid is sensitive or resistant

Sensitive:
- IV ceftriaxone (first line due to rising fluoroquinolone resistance) or PO ciprofloxacin
- others: amoxicillin, co-trimoxazole, chloramphenicol
Resistant:
- PO azithromycin
ADD corticosteroids in severe typhoid cases (shock/delirium): help reduce mortality

Follow up stool cultures (2w after abx for 3 w, weekly)

• to look for chronic carriers (pos even at 6m)
• us gb - check for gallstones KIV cholecystectomy

Question 15

How to prevent typhoid

Answer 15

1. food and water hygiene
2. Vaccination (cover only S typhi - not for s paratyphi/ non typhoidal)
   - IM typhim Vi: 2-3 y
   - PO oral typhoid (live): 5y

Question 16

Causes of prolonged fever>7days

Answer 16

• Enteric fever (Typhoid)
• Endocarditis
• Tuberculosis
• Brucellosis
• Visceral Leishmaniasis
• Q fever (Coxiella burnetti)
• Abscess
• Non infectious causes

Question 17

which vaccines are compulsory by law

Answer 17

• diphtheria

- measles

Question 18

what are the components in 5-in-1 vaccine

Answer 18

Diphtheria/Pertussis/Tetanus
Polio
H flu Type B

Question 19

Antibiotic resistance types

- how to differentiate

Answer 19

Porin loss: associated with carbapenem resistance
Efflux pump: assoc with multi drug resistance because it is naturally resistant to all classes of abx.

Beta-lactamases

1. ESBL: able to hydrolyse 3rd gen cephalosporin but not 4th gen cefepime
2. AmpC: resistant to all cephalosporin except for 4th gen cefepime and carbapenems
3. Carbapenemase: can hydrolyse penicillin, cephalosporin, and carbapenem

Question 20

Which organisms carry the AmpC gene

Answer 20

ESCAPPM

• Enterobacter spp
• Serratia spp
• Citrobacter freundii
• Aeromonas spp
• Proteus vulgaris
• Providencia spp
• Morganella marganii

Question 21

how to treat PCP in HIV patients

Answer 21

Determine severity
moderate-severe PCP: PaO2<70 or alveolar-arterial gradient >35mmhg: add corticosteroids within 72h

+

clindamycin-primaquine PO or
IV pentamidine

Question 22

What is associated with eschar

Answer 22

scrub typhus - orientia tsutsugamushi