A 32-year-old man from Mumbai presents with jaundice, dark urine, and abdominal discomfort for 2 weeks. He reports a history of needle-stick injury 6 months ago while working as a healthcare worker. On examination, he is icteric with hepatomegaly. Liver function tests show ALT 2800 IU/L, AST 2200 IU/L, bilirubin 8.5 mg/dL. Serology reveals: HBsAg positive, anti-HBc positive, IgM anti-HBc positive, anti-HBs negative, HBeAg positive, anti-HBe negative. What is the most likely interpretation of these serological markers?

Explanation

## Interpretation of Hepatitis B Serology ### Clinical Context The patient presents with acute hepatitis (markedly elevated transaminases, hyperbilirubinemia, jaundice) 6 months after a needle-stick injury, consistent with the incubation period of hepatitis B (45–180 days). ### Serological Marker Analysis | Marker | Result | Interpretation | |--------|--------|----------------| | HBsAg | Positive | Acute or chronic infection | | Anti-HBc | Positive | Exposure to HBV (present in both acute and chronic) | | **IgM anti-HBc** | **Positive** | **Indicates ACUTE infection** | | Anti-HBs | Negative | No immunity (would appear after recovery) | | HBeAg | Positive | High viral replication, high infectivity | | Anti-HBe | Negative | Consistent with acute phase | ### Key Differentiator **Key Point:** IgM anti-HBc is the single most reliable marker of **acute hepatitis B infection**. It appears early (within 1–2 weeks of symptom onset) and persists for 6 months, then is replaced by IgG anti-HBc in chronic infection. **High-Yield:** The serological pattern HBsAg(+), anti-HBc(+), **IgM anti-HBc(+)**, anti-HBs(−) is pathognomonic for acute HBV infection. ### Why This Is Acute, Not Chronic - **Acute infection:** IgM anti-HBc present → recent/active infection - **Chronic infection:** IgM anti-HBc absent; only IgG anti-HBc present - **Resolved infection:** HBsAg negative, anti-HBs positive - **Vaccination:** Anti-HBs positive only; HBsAg and anti-HBc both negative **Clinical Pearl:** In healthcare workers with occupational exposure, post-exposure prophylaxis (hepatitis B immunoglobulin + vaccination) within 24 hours can reduce transmission risk by >90%; however, if infection has already occurred (as in this case), acute hepatitis B typically resolves spontaneously in >95% of immunocompetent adults.