Virology USMLE Step 1 Practice Question
A 45-year-old woman with a 10-year history of chronic hepatitis B (HBsAg positive, anti-HBc positive) presents to the emergency department with jaundice, right upper quadrant pain, and malaise for 5 days. She reports no recent medication changes, denies acetaminophen or alcohol use, and has no known exposure to other hepatitis viruses. Vital signs: BP 134/88 mmHg, HR 108 bpm, temperature 38.2°C. Laboratory studies show: AST 4,100 U/L, ALT 3,800 U/L, total bilirubin 5.8 mg/dL, INR 1.6, albumin 2.8 g/dL, platelet count 92,000/μL. HBeAg is positive, and HBV DNA is 8.9 × 10^7 copies/mL. Abdominal ultrasound shows no cirrhotic features. Which of the following best explains the acute hepatic decompensation in this chronically infected patient?
Answer choices
- ASuperinfection with hepatitis D virus (HDV) leading to enhanced viral replication
- BLoss of HBeAg with development of anti-HBe antibodies, indicating viral clearance
- CReactivation of hepatitis B viral replication from an occult HBV carrier state with integration into host chromosome
- DEmergence of a precore or basal core promoter HBV mutant with continued high viral replicationCorrect answer
- ESimultaneous acute infection with hepatitis A virus in a previously non-immune patient
- FAutoimmune hepatitis triggered by HBV antigen presentation to naive T cells
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