Epidemiology
- 50% acquired during travels abroad
Etiology
- Contaminated water and food (e.g., raw shellfish)
Pathophysiology
- HAV is not cytopathic in itself; research suggests that liver damage is caused by cellular immunity (especially CD8+ T cells).
Clinical features
Tip
- Unlike hepatitis B or C, HAV infection is a self-limiting disease that is not associated with an asymptomatic viral carrier state and does not progress to chronic hepatitis, cirrhosis, or hepatocellular carcinoma.
- HAV only has acute phase, HCV only has chronic phase
- Disease Course: Self-limiting; no chronic carrier state.
- Children (<6 years): Typically asymptomatic or mild non-specific symptoms.
- Adults & Older Children (Symptomatic):
- Prodrome (1–2 weeks): Low-grade fever, fatigue, malaise, N/V, anorexia, RUQ abdominal pain, aversion to smoking.
- Icteric Phase: Jaundice, scleral icterus, dark urine (bilirubinuria), pale/clay-colored stools (acholic stools), generalized pruritus.
- Resolution of symptoms
- PE: Hepatomegaly, RUQ tenderness, mild splenomegaly.
Diagnostics
- Liver biopsy: not routinely indicated
- Periportal inflammation (mononuclear cell infiltration)
- Hepatocyte swelling
- Ballooning degeneration
- Bridging necrosis
- Councilman bodies (apoptotic hepatocytes)
Treatment
- Acute Infection: Supportive care (hydration, rest, avoidance of hepatotoxic substances/alcohol).
- Post-Exposure Prophylaxis (PEP) (given to non-immune contacts within 2 weeks of exposure):
- Age 1–40 years: HAV vaccine alone.
- Age <1 year, >40 years, immunocompromised, or chronic liver disease: HAV vaccine + HAV immunoglobulin (IG) (or IG alone if vaccine C/I).
- Pre-Exposure Prophylaxis: HAV vaccine (2-dose series) routinely recommended at age 12–23 months, or prior to travel to endemic areas.
Complications
- Fulminant Hepatic Failure: Rare (<1%), but higher risk in elderly pts or underlying chronic liver disease (e.g., HBV, HCV, cirrhosis).
- Features: Acute liver failure w/ hepatic encephalopathy and coagulopathy (elevated PT/INR).
- Relapsing Hepatitis: Occurs in 3–20% of pts within 4–15 weeks after initial recovery; generally mild and self-limiting.
- Cholestatic Hepatitis: Marked by prolonged jaundice and pruritus (>12 weeks) w/ elevated ALP; eventual resolution.