What are the common tropical illnesses that cause jaundice and elevated liver enzymes (transaminases)?

Common Tropical Illnesses Causing Jaundice and Elevated Transaminases

The most common tropical infections causing jaundice with elevated transaminases are malaria (particularly Plasmodium falciparum), leptospirosis, enteric fever (typhoid/paratyphoid), dengue, and rickettsial infections (scrub typhus and murine typhus). 1, 2

Primary Tropical Causes by Geographic Region

Malaria (Plasmodium falciparum)

• Malaria is the single most important potentially fatal cause requiring immediate exclusion in all febrile travelers from the tropics, especially sub-Saharan Africa. 1
• Accounts for 28-47% of febrile jaundice cases in travelers returning from Africa, but only 4-11% from Asia. 1
• Malarial hepatitis presents with disproportionate hyperbilirubinemia (mean 12.7 mg/dL) but only mild-to-moderate transaminase elevation (AST ~213 IU, ALT ~287 IU), which helps differentiate it from viral hepatitis. 3, 4
• Clinical predictors include splenomegaly (likelihood ratio 5.1-13.6), thrombocytopenia (LR 2.9-11), and hyperbilirubinemia (LR 5.3-7.3). 1
• Hepatomegaly is always present in malarial hepatitis. 3

Leptospirosis

• Presents with jaundice, fever, and hepatorenal syndrome. 1
• Accounts for 6.8% of hospitalized cases with jaundice/hepatitis in Southeast Asia. 2
• Key diagnostic clues: proteinuria and hematuria on urinalysis, exposure to contaminated water or soil. 1
• Blood cultures (if obtained <5 days from symptom onset) and CSF cultures are diagnostic. 1
• Empirical treatment with doxycycline or penicillin should be initiated on clinical suspicion, though efficacy diminishes once jaundice develops. 1

Enteric Fever (Typhoid/Paratyphoid)

• Most common serious tropical disease requiring treatment in travelers from Asia after malaria is excluded. 1
• Accounts for 3-17% of febrile jaundice cases in Asian returnees versus <1% in African returnees. 1
• Constitutes 34% of tropical infections causing acute hepatitis in endemic areas. 5
• Clinical predictors: return from South-East Asia (LR 4.0-4.1), splenomegaly (LR 5.9-10). 1
• Blood cultures have 40-80% sensitivity in the first week; bone marrow cultures have higher sensitivity. 1

Dengue Fever

• Accounts for 13-18% of febrile cases in Asian returnees and 8-13% in Latin American returnees. 1
• Represents 8.4% of hospitalized jaundice/hepatitis cases in Southeast Asia and 26% of tropical infections causing acute hepatitis. 2, 5
• Clinical predictors: return from Asia (LR 1.6-7.9), skin rash (LR 2.8), leukopenia (LR 3.3), thrombocytopenia. 1, 5
• Dengue PCR is diagnostic during days 1-8 post-symptom onset; IgM serology after day 5. 1

Rickettsial Infections (Scrub Typhus, Murine Typhus)

• Combined with leptospirosis, account for 12.8% of jaundice/hepatitis cases in Southeast Asia. 2
• Scrub typhus represents 20% of tropical infections causing acute hepatitis. 5
• Characteristic features: meningism, relatively low AST/ALT elevation despite jaundice, exposure to ticks in game parks. 1, 2
• Clinical predictors: skin rash (LR 3.8), skin ulcer/eschar (LR 11.1). 1
• Empirical doxycycline therapy is appropriate and cost-effective when rickettsial infection or leptospirosis is suspected. 1, 2

Less Common but Important Tropical Causes

Viral Hemorrhagic Fevers (VHF) and Yellow Fever

• Yellow fever is endemic in sub-Saharan Africa and South America. 1
• Always contact regional infectious disease center when VHF is suspected; PCR to reference laboratory is required. 1
• Vaccination history must be confirmed to interpret yellow fever results. 1

Acute Schistosomiasis (Katayama Fever)

• Occurs 4-8 weeks post-exposure to contaminated freshwater. 1
• Accounts for 3-6% of febrile cases in African returnees. 1
• Eosinophilia is the key diagnostic clue (LR 32). 1
• Empirical praziquantel with consideration of steroids is appropriate for suggestive presentation. 1

Amoebic Liver Abscess

• Serology >92% sensitive at presentation; ultrasound confirms abscess. 1
• Empirical tinidazole/metronidazole is indicated with suggestive clinical history and abscess on ultrasound. 1
• Note: 25% of individuals in endemic areas have positive serology without active disease. 1

Key Distinguishing Features from Viral Hepatitis

Tropical infections causing acute hepatitis differ from acute viral hepatitis in several critical ways: 5

• Persistent fever after onset of jaundice (88% of tropical infections vs. 0% in viral hepatitis) 5
• Thrombocytopenia (odds ratio 4.237 for tropical infections) 5
• Milder hyperbilirubinemia and lower transaminase elevation 5, 3, 4
• Presence of skin rash (16% vs. 0%) 5
• Associated headache, myalgia, leukopenia, hyponatremia 5

Diagnostic Algorithm

Initial workup for all patients with tropical exposure and jaundice/elevated transaminases: 1

1. Three malaria thick films/rapid diagnostic tests over 72 hours - mandatory first step 1
2. Two sets of blood cultures before antibiotics - sensitivity up to 80% for typhoid 1
3. Complete blood count - assess for thrombocytopenia, leukopenia, eosinophilia 1
4. Fractionated bilirubin, AST, ALT, alkaline phosphatase 1
5. Urinalysis - proteinuria/hematuria suggests leptospirosis 1
6. Serology panel: hepatitis A/B/C/E IgM, leptospirosis, dengue, rickettsia 2
7. Dengue PCR if <8 days from symptom onset 1
8. Abdominal ultrasound - evaluate for hepatosplenomegaly, abscess 1

Critical pitfall: Anti-HAV IgM has high false-positive rate due to polyclonal B-cell activation in tropical infections; 82% of positive results may represent cross-reactivity rather than acute HAV infection. 2

Empirical Treatment Considerations

When diagnostic testing is delayed or unavailable in endemic areas: 2

• Doxycycline empirically covers leptospirosis, scrub typhus, and murine typhus - collectively representing 12.8% of cases and associated with good treatment response 2
• This represents a cost-effective intervention in resource-limited settings where virological diagnosis is unavailable 2