Acute hepatitis A

**Definition:** Acute liver injury and inflammation caused by recent and short-term (less than 6 months) infection with hepatitis A virus (HAV). Transmission is by the faecal-oral route. Diagnosis is confirmed by presence of IgM-anti-HAV in serum. Clinical features, if they occur, are characterised by anorexia, nausea and fever, with jaundice in severer cases.

**Long definition:** Acute hepatitis A is acute liver injury caused by infection with hepatitis A virus (HAV), which is a small, 27nm in length, cubically symmetrical RNA picorna virus (enterovirus type 72). HAV is usually spreads by faecal-oral transmission. The incubation period is 2 to 6 week after infection. Acute hepatitis A is diagnosed by positive serum IgM anti-HAV and usually shows a self-limiting course although fulminant course can occur rarely (the risk increases with age) and 5-10% of cases can be complicated by cholestasis persisting up to 6 weeks and 0.2% developing acute liver failure. It never progresses to chronic hepatitis or cirrhosis.

**Exclusions:** - Infectious liver disease - Acute or subacute hepatic failure