Hepatitis C, B, D, and A: contrasting features and liver function abnormalities in heroin addicts.

Over 90% of intravenous heroin addicts (IVHAs) carry the hepatitis C virus (HCV). The other hepatitis viruses, A, B, D, and G are relatively unimportant in IVHAs compared to HCV although active hepatitis B may demonstrate a chronic, degenerative course identical to that of HCV. The clinical course of HCV and active hepatitis B may span three or more decades. It is helpful to classify patients as in the active, cirrhosis, or liver failure stages. Only in the active, early stage are the liver enzymes, ALT and AST, likely to be elevated. It is this stage that will most likely respond to antiviral therapy. HCV has so many extra-hepatic manifestations including immune suppression, collagen diseases, and possibly lymphoma and leukemia that the disease is best termed HCV syndrome rather than simple hepatitis.