Hepatitis B in Children

Abstract

1. Adam R. Davis, MD* 2. Philip Rosenthal, MD† 1. *Clinical Fellow, Division of Pediatric Gastroenterology, Hepatology and Nutrition, University of California, San Francisco, Calif 2. †Professor of Pediatrics and Surgery; Medical Director, Pediatric Liver Transplant Program; Director, Pediatric Hepatology, University of California, San Francisco, Calif After completing this article, readers should be able to: 1. Describe the structure of the hepatitis B virus and the function of its proteins. 2. Delineate the mode of transmission of the virus and identify at-risk populations. 3. Interpret the results of screening laboratory tests for hepatitis B. 4. Describe the various disease presentations and the natural history and complications of chronic hepatitis B infection. 5. List the currently approved therapies for hepatitis B and identify when patients are most likely to benefit from intervention. 6. List the current recommendations for immunoprophylaxis in infants, children, and adolescents. One third of the world's population has been infected by the hepatitis B virus (HBV), causing an enormous worldwide burden of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Although the virus can infect people of any age, those who are infected perinatally or as children are at greatest risk for developing the potentially fatal complications of the infection. Approval of the hepatitis B vaccine in 1982 has been the most important development in the clinical approach to this virus, changing the major goal from treatment to prevention. In this article, we review the nature of the virus, its epidemiology, serologic markers of disease, clinical manifestations of infection, the prevention of transmission, and current treatments. HBV is a member of the hepadnavirus family, which is named for its hepatotropic nature and its double DNA genome. It is the only member of the family that causes disease in humans. The virion has two forms: an empty envelope that does not have the potential to infect or replicate and a complete virion. The complete virion is comprised of an envelope containing the capsid, a DNA polymerase, and the viral DNA (Figure⇓). The DNA is 3.2 kilobases long and circular. Hepadnaviruses are unique among DNA viruses in that they are partially double-stranded and …