Viral Hepatitis — Written Clinical Reasoning

SAQ 1 — Chronic hepatitis B with probable cirrhosis (20 marks, 30 minutes)

Prompt: A 54-year-old man born in Vietnam has known chronic hepatitis B and has never been treated. Results: HBsAg positive, HBeAg negative, anti-HBe positive, HBV DNA 45,000 IU/mL, ALT 118 U/L. Transient elastography reads 18 kPa and his platelet count is 110 ×10⁹/L. He has type 2 diabetes and obesity, and lives with his wife and two adult children. Outline your interpretation and management, including antiviral selection, surveillance and the obligations to his family. ^[1]

Model Answer

Interpretation (5 marks):

• Chronic infection is defined by HBsAg present for at least 6 months. ^[1]
• AASLD defines immune-active disease as ALT at least twice the upper limit of normal plus HBV DNA above 2,000 IU/mL in HBeAg-negative patients. It recommends an ALT upper limit of 35 U/L for men, so an ALT of 118 U/L with HBV DNA of 45,000 IU/mL is HBeAg-negative immune-active disease. ^[1]
• Stage fibrosis carefully: AASLD notes that noninvasive methods overestimate fibrosis if high levels of necroinflammation, as reflected by elevated ALT, are present. ^[1]

Antiviral therapy (5 marks):

• AASLD recommends antiviral therapy for immune-active disease, and therapy for immune-active disease with cirrhosis if HBV DNA is above 2,000 IU/mL, regardless of ALT. ^[1]
• The preferred agents are peg-IFN, entecavir, TDF and TAF. Consider TAF or entecavir in patients with, or at risk of, renal dysfunction or bone disease. The approved TAF dose is 25 mg once daily, and all nucleos(t)ide analogues except TAF need dose adjustment when creatinine clearance is below 50 mL/min. ^[1]
• Peg-IFN is contraindicated in decompensated cirrhosis. ^[1]

HCC surveillance (4 marks):

• AASLD recommends ultrasound, with or without AFP, every 6 months for all HBsAg-positive patients with cirrhosis. Antiviral therapy does not eliminate HCC risk, so surveillance continues. ^[1]
• The 2023 AASLD HCC guidance recommends surveillance with ultrasound plus AFP about every 6 months. ^[3]

Cofactors (2 marks):

• Raised ALT may also come from causes other than hepatitis B, including drug-induced liver injury, alcohol-associated liver disease and fatty liver. AASLD's conservative approach is abstinence or minimal alcohol, and patients with chronic hepatitis B should be immunised against hepatitis A if not immune. ^[1]

Family (2 marks):

• Household members and sexual partners should be vaccinated if they test negative for HBV serologic markers. ^[1]
• CDC lists household contacts of people with known HBV infection among those to test, using HBsAg, anti-HBs and total anti-HBc. ^[6]

If he decompensates (2 marks):

• Patients with decompensated cirrhosis should be referred for liver transplantation and started on antiviral therapy at the same time. ^[1]