A 28-year-old man from rural Maharashtra presents with jaundice, dark urine, and abdominal pain for 5 days. He reports consuming water from a local well 3 weeks ago. On examination, he is afebrile, has hepatomegaly, and mild splenomegaly. Laboratory findings: ALT 2400 IU/L, AST 1800 IU/L, bilirubin 8.2 mg/dL, albumin 3.8 g/dL, PT normal. Serology shows anti-HAV IgM positive, anti-HAV IgG negative. Which of the following is the most likely diagnosis and the expected clinical course?

Explanation

## Diagnosis: Acute Hepatitis A ### Clinical Presentation & Epidemiology **Key Point:** The combination of acute onset jaundice, dark urine, hepatomegaly, waterborne exposure (well water), and fecal–oral transmission route in a young immunocompetent adult strongly suggests hepatitis A. **High-Yield:** Hepatitis A is transmitted via the fecal–oral route; contaminated water is a classic source in endemic areas like rural India. ### Serological Interpretation | Marker | Finding | Interpretation | |--------|---------|----------------| | Anti-HAV IgM | Positive | Acute infection (current/recent) | | Anti-HAV IgG | Negative | No prior immunity | | HAV RNA | Would be detectable | Confirms active viral replication | **Key Point:** Anti-HAV IgM is the diagnostic gold standard for acute hepatitis A. IgG appears later and confers lifelong immunity. ### Laboratory Pattern - Markedly elevated transaminases (ALT > AST, typical of acute viral hepatitis) - Hyperbilirubinemia with cholestasis - **Preserved synthetic function** (normal PT, normal albumin) — critical distinguishing feature ### Natural History & Prognosis **Clinical Pearl:** Hepatitis A in immunocompetent adults has a benign course: 1. Acute phase: 4–6 weeks of symptomatic illness 2. Convalescence: 2–12 weeks of gradual recovery 3. **No chronic infection** — 100% clearance of virus 4. Fulminant hepatic failure rare (< 1% in adults, higher in elderly or those with pre-existing liver disease) **Mnemonic: HAV = "Hepatitis A = Always acute"** — never becomes chronic. ### Why This Patient Will Recover - Young, immunocompetent host - Preserved synthetic function (normal PT) - No evidence of decompensation - Natural history of HAV is self-limited acute hepatitis followed by complete resolution **High-Yield:** Hepatitis A does NOT require specific antiviral therapy; management is supportive. Patients should avoid alcohol and hepatotoxic drugs during recovery.