A 48-year-old woman with a 20-year history of intravenous drug use presents with fatigue, abdominal pain, and jaundice. She reports a new sexual partner 3 months ago. Examination reveals hepatomegaly and ascites. Labs show: ALT 450 IU/L, AST 680 IU/L, bilirubin 4.2 mg/dL, albumin 2.8 g/dL, PT 16 seconds, platelets 95,000/μL. HBsAg is positive, anti-HBc is positive, anti-HBs is negative. Anti-HDV is positive. HCV antibody is positive with detectable HCV RNA. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Chronic Hepatitis B and C Co-infection with Chronic Hepatitis D ### Serological Interpretation **Key Point:** The serological pattern indicates long-standing chronic viral hepatitis, not acute infection. | Marker | Result | Interpretation | |--------|--------|----------------| | HBsAg | Positive | Indicates HBV infection (acute or chronic) | | Anti-HBc | Positive | Indicates past or ongoing HBV exposure | | Anti-HBs | Negative | Rules out immunity/recovery; consistent with chronic infection | | Anti-HDV | Positive | Indicates HDV co-infection | | HCV antibody | Positive | Indicates HCV exposure | | HCV RNA | Detectable | Indicates active HCV replication (chronic infection) | ### Distinguishing Chronic from Acute **High-Yield:** - **Acute HBV:** Anti-HBc IgM positive, HBsAg positive, anti-HBs negative (early phase) - **Chronic HBV:** Anti-HBc IgG positive (total anti-HBc), HBsAg positive, anti-HBs negative - The stem does NOT specify anti-HBc IgM; the presence of anti-HBc alone indicates chronic infection in an HBsAg-positive patient ### Clinical Features Supporting Chronicity - **20-year IVDU history:** High risk for chronic HBV and HCV acquisition - **Ascites, low albumin (2.8), elevated PT:** Signs of decompensated cirrhosis - **Thrombocytopenia (95,000):** Portal hypertension from cirrhosis - **Moderate transaminitis (not >1000):** Consistent with chronic rather than acute hepatitis ### HDV Superinfection Pattern **Clinical Pearl:** HDV can only infect in the presence of HBV. The positive anti-HDV indicates HDV co-infection. Given the chronic HBV serology and clinical decompensation, this is chronic HDV, not acute superinfection. ### Why Not Acute Superinfection? - Acute HDV superinfection on chronic HBV typically presents with a sudden flare (marked transaminitis >1000, rapid bilirubin rise) - This patient has moderate transaminitis and established cirrhosis (ascites, low albumin), suggesting long-standing disease - The clinical picture is consistent with progressive cirrhosis from multiple chronic viruses ```mermaid flowchart TD A[HBsAg positive<br/>Anti-HBc positive<br/>Anti-HBs negative]:::outcome --> B{Anti-HBc IgM?}:::decision B -->|Positive| C[Acute HBV]:::outcome B -->|Negative/Not specified| D[Chronic HBV]:::outcome D --> E[Anti-HDV positive]:::outcome E --> F{Clinical decompensation<br/>Ascites, low albumin?}:::decision F -->|Yes| G[Chronic HDV<br/>with cirrhosis]:::outcome F -->|No| H[Acute HDV<br/>superinfection]:::outcome D --> I[HCV RNA detectable]:::outcome I --> J[Chronic HCV co-infection]:::outcome ``` **High-Yield:** The combination of HBV + HCV + HDV represents triple infection with accelerated liver disease progression. HDV can only exist with HBV; HCV is independent. The patient has chronic infection with all three viruses and established cirrhosis. [cite:Harrison 21e Ch 297]