Occult HBV Reactivation — RACP Adult Medicine MCQ

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ModerateInfectious DiseasesOccult HBV ReactivationRACP Adult Medicine

A 55-year-old man develops hepatitis B reactivation (rising HBV DNA, ALT 800 U/L) after receiving rituximab for lymphoma. He was HBsAg negative but anti-HBc positive (past exposure/resolved infection) before treatment. What is this phenomenon called?

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Correct answer: D — Chronic hepatitis B flare

Rituximab (and other anti-CD20 agents) causes profound B-cell depletion that can allow reactivation of hepatitis B even in patients with 'resolved' past infection (HBsAg negative, anti-HBc positive). This is because cccDNA persists in hepatocytes indefinitely after initial infection. When immune surveillance is removed by rituximab, HBV replication resumes. This can cause severe hepatitis, liver failure, and death. ALL patients should be tested for HBsAg AND anti-HBc before rituximab. Anti-HBc positive patients should receive antiviral prophylaxis (entecavir or tenofovir) during rituximab and for ≥12–18 months after cessation, with HBV DNA monitoring.

Reference: eTG – 2025 – Antibiotic Guidelines; AASLD – 2018 – HBV Reactivation