Paper II
Question
Discuss Hepatitis B infection under the following headings:- (
- (a) Clinical features ( 5 mark(s)
- (b) Gross and microscopic changes in liver ( 5 mark(s)
- (c) Complications 5 mark(s)
Answer
(a) Clinical features
- Incubation period of 1–6 months
- Acute hepatitis: Prodromal phase (fatigue, anorexia, nausea, low-grade fever), followed by icteric phase (jaundice, dark urine, pale stools, right upper quadrant discomfort, hepatomegaly) — most adult infections resolve completely
- Chronic hepatitis: Develops in a proportion of infected individuals (higher risk with perinatal/early childhood infection), often asymptomatic or with non-specific fatigue, may progress silently to cirrhosis over years
- Fulminant hepatitis: Rare, severe acute liver failure with encephalopathy and coagulopathy
- Extrahepatic manifestations: polyarteritis nodosa, membranous glomerulonephritis (immune complex-mediated)
(b) Gross and microscopic changes in liver
Gross
- Acute hepatitis: liver may be normal-sized or slightly enlarged, red-tan, soft
- Chronic hepatitis with cirrhosis: shrunken, nodular, firm liver with a diffusely irregular surface
Microscopic
- Acute hepatitis: Diffuse hepatocyte swelling (ballooning degeneration), individual cell necrosis with acidophil (Councilman) bodies, mixed portal and lobular inflammatory infiltrate, Kupffer cell hyperplasia, cholestasis
- Chronic hepatitis: Portal/periportal inflammation with interface hepatitis (piecemeal necrosis), progressive fibrosis (periportal → bridging → cirrhosis), ground-glass hepatocytes (finely granular eosinophilic cytoplasm from HBsAg accumulation)
(c) Complications
- Chronic hepatitis and progression to cirrhosis
- Hepatocellular carcinoma (markedly increased risk with chronic HBV infection, can occur even without cirrhosis due to direct oncogenic viral integration)
- Fulminant hepatic failure (rare, acute)
- Extrahepatic immune complex-mediated disease (polyarteritis nodosa, membranous glomerulonephritis)
- Superinfection with Hepatitis D virus (worsens prognosis significantly)