A 32-year-old man from rural Maharashtra presents with jaundice, dark urine, and pale stools for 10 days. He reports consuming contaminated water from a well 4 weeks ago. On examination, he is afebrile with hepatomegaly and mild splenomegaly. Laboratory investigations show: Total bilirubin 8.2 mg/dL, ALT 1840 IU/L, AST 1620 IU/L, ALP 320 IU/L, albumin 3.8 g/dL, PT-INR 1.1. Serology: Anti-HAV IgM positive, Anti-HBc negative, Anti-HCV negative. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Acute Hepatitis A ### Key Clinical Features **Key Point:** Anti-HAV IgM positivity is the gold standard marker for acute hepatitis A infection, indicating recent primary infection. The patient presents with a classic vignette of acute hepatitis A: - Fecal-oral transmission (contaminated water exposure) - Incubation period of 2–7 weeks (4 weeks fits perfectly) - Acute onset of jaundice with constitutional symptoms - Marked transaminitis (ALT > AST, typical of viral hepatitis) - Preserved synthetic function (albumin 3.8 g/dL, INR 1.1) ### Serological Interpretation | Marker | Result | Interpretation | |--------|--------|----------------| | Anti-HAV IgM | Positive | Acute hepatitis A | | Anti-HBc | Negative | No HBV exposure | | Anti-HCV | Negative | No HCV exposure | | PT-INR | 1.1 | Normal coagulation | **High-Yield:** Anti-HAV IgM appears early in infection (at symptom onset) and persists for ~6 months. Anti-HAV IgG (not tested here) appears later and confers lifelong immunity. ### Why This Is NOT Fulminant Hepatic Failure **Clinical Pearl:** Fulminant hepatic failure in hepatitis A is defined by: - Hepatic encephalopathy (absent here) - Coagulopathy with PT-INR > 1.5 (INR is 1.1 — normal) - Rapid deterioration of synthetic function (albumin is preserved) The patient has uncomplicated acute hepatitis A with excellent prognosis. Fulminant HAV occurs in <0.5% of cases in immunocompetent adults. ### Differential Exclusion **Why NOT hepatitis B or E?** - Anti-HBc negative excludes any HBV exposure (acute or chronic) - Hepatitis E typically presents with cholestatic features (high ALP relative to transaminases), which is NOT prominent here (ALP 320 vs ALT 1840) ## Prognosis & Management **Key Point:** Acute hepatitis A is self-limited in immunocompetent patients. No antiviral therapy is needed; supportive care and monitoring of coagulation are sufficient.