[Clinical aspects and therapy of viral hepatitis].

Acute hepatitis can be caused by the enterically spread hepatitis A and E viruses and the parenterally spread hepatitis B, C or D viruses. The clinical features of acute viral hepatitis are similar among the five viruses and include non-specific symptoms and icterus. In general, a specific therapy is not necessary, but patients with fulminant hepatitis may require liver transplantation. For acute hepatitis C, the effect of interferon-alpha on the risk of chronicity is evaluated in clinical trials. Chronic hepatitis is defined as inflammatory reaction in the liver that continues without improvement for at least 6 months after infection with hepatitis B, C or D viruses. Hepatitis B resolves in more than 90% of the patients, but chronic infection can lead to liver cirrhosis and hepatocellular carcinoma. Chronic hepatitis C is an insidious disease, because early diagnosis is missed easily due to asymptomatic presentation and about 70% of infected patients develop chronic hepatitis. The benefits of interferon-alpha and/or nucleoside analogues have been proven in recent clinical trials that show sustained responses in more than a third of all patients with chronic viral hepatitis. The future treatment of chronic viral hepatitis will likely include immunomodulation and gene therapy.