Acute and chronic viral hepatitis.

Hepatitis A, B, C, D, E, and G are important causes of viral hepatitis. It is estimated that there are at least 32,000 new cases of hepatitis A, 300,000 new cases of hepatitis B, and 150,000 new cases of hepatitis C each year in the United States alone. Risk factors for hepatitis infection include sexual activity with multiple partners, intravenous drug use or sharing cocaine straws, tattooing or body piercing, exposure to blood and body fluids through health-care work, and having a blood transfusion or transplant. Diagnostic markers are important to determine the type of hepatitis and to differentiate acute from chronic infection. Up to 5% of adult patients infected with hepatitis B virus and up to 80% of those infected with hepatitis C virus become chronic carriers. Whereas acute hepatitis C virus infection is usually mild, chronic hepatitis C infection develops insidiously after an average of 10 years and may lead to cirrhosis and possibly hepatocellular carcinoma. Currently, interferon-alpha is the only FDA-approved agent to treat chronic hepatitis B and C and relapses are common with hepatitis C infection. There are many clinical trials using other antivirals and combination therapies to treat these chronic infections. Prevention through patient education of high-risk behaviors and immunization remain the best defense against acute and chronic viral hepatitis.