Hepatitis A , caused by infection with the Hepatitis A virus (HAV), has an incubation period of approximately 28 days (range: 15–50 days). HAV replicates in the liver and is shed in high concentrations in feces from 2 weeks before to 1 week after the onset of clinical illness. HAV infection produces a self-limited disease that does not result in chronic infection or chronic liver disease. Relapsing HAV infection occurs in approximately 10% of patients 1-4 months after the initial episode and results in full recovery. Chronic active hepatitis, which can be seen in hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, does not occur in HAV infection. A chronic carrier state is not seen with HAV infection. Physical examination The general appearance is that of mild-to-moderate illness. A patient who appears severely ill is likely to have hepatitis of another cause or an atypical course. Mild hepatomegaly and right upper quadrant tenderness may be present. Clinical jaundice is present in two thirds of symptomatic patients.... Liver Function Tests Liver inflammation during hepatitis A virus (HAV) infection can be identified by elevations in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltranspeptidase (GGTP; also known as gamma glutamyltransferase [GGT]) levels. Increases in ALT and AST levels are seen most consistently, and the values are usually 4-100 times the normal levels. Elevations in ALT and AST levels may precede the onset of symptoms by a week or more and usually peak within 3-10 days after onset of clinical illness. Serum bilirubin levels, although elevated, usually remain below 10 mg/dL and peak after 1-2 weeks of illness. Specific antibody tests for HAV confirm infection. Anti-HAV immunoglobulin M (IgM) is present at the onset of symptoms, and its level remains high for 4-8 weeks. It usually disappears by 4-6 months, but occasionally it persists for a longer period. Anti-HAV immunoglobulin G (IgG) becomes detectable shortly after the IgM titer appears and usually increases as the IgM level decreases. IgG persists for life and provides ongoing immunity against reinfection. Ultrasonography Ultrasonography of the liver may be helpful when cholelithiasis is a consideration. However, imaging studies are generally not necessary.
Posted on: Mon, 13 Oct 2014 09:17:58 +0000
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