Rheumatic disorders associated with hepatitis C.

The hepatitis C virus (HCV) is a common virus of world-wide distribution affecting up to 3% of the world's population. Its genetic diversity, with multiple subtypes, and existence in the form of quasispecies in individual hosts, is, in part, responsible for high rates of chronic infection. Individuals with HCV infection will undoubtedly present to rheumatologists and other health care professionals with rheumatic and other immunological disorders related to what was usually a remote and asymptomatic acute infection. The goals of this review are: (1) to summarize clinical observations regarding rheumatological and immunological diseases linked with HCV infection; (2) to provide relevant information on the molecular biology of HCV; (3) to discuss the state of the art regarding the use of diagnostic studies; (4) to consider the differential diagnosis of liver disease and rheumatic disorders; and (5) to provide a practical guide to the history, physical examination, laboratory work-up, disease monitoring, and therapy of HCV patients with rheumatic disorders.