Acute and Chronic VIRAL HEPATITIS

Reprinted with permission from CME August 2005 Vol. 23 No. 8 M any viruses can infect the liver, but are usually not able to enter hepatocytes due to certain barriers such as the activity of Kupffer cells. Viruses such as Epstein-Barr virus and cytomegalovirus frequently cause hepatitis as part of a systemic illness, but this is seldom the main symptom. The typical hepatitis virus is able to enter and replicate in the hepatocyte and causes hepatitis as the primary disease. Only these hepatotropic viruses, hepatitis A, B, C, and E, will be discussed here. These viruses are collectively responsible for most acute and chronic hepatitis worldwide. For example, chronic hepatitis B and C currently affect approximately 600 million people, and hepatitis A and E have been responsible for large pointsource outbreaks affecting hundreds of thousands of people. Because hepatitis D and E are not thought to be endemic in South Africa, they will not be discussed in this article in any detail. The virological, epidemiological and clinical characteristics of these viruses are contrasted in Table I. ACUTE VIRAL HEPATITIS