hepatic and biliary disorders
Hepatitis B, Acute
Key Points
Hepatitis B is often transmitted by parenteral contact with contaminated blood but can result from mucosal contact with other body fluids. Infants born to mothers with hepatitis B have a 70 to 90% risk of acquiring infection during delivery unless the infants are treated withhepatitis B immune globulin(HBIG) and are vaccinated after delivery; risk is also decreased by treating actively infected third trimester pregnant mothers who have high viral loads with tenofovir. Chronic infection develops in 5 to 10% of patients with acute hepatitis B and often leads to cirrhosis and/or hepatocellular carcinoma. Diagnose by testing for hepatitis B surface antigen and other serologic markers. Treat supportively. Routine vaccination beginning at birth is recommended for all. Postexposure prophylaxis consists of HBIG and vaccine; HBIG probably does not prevent infection but may prevent or attenuate clinical hepatitis. 