Extrahepatic manifestations of viral hepatitis.

Recent evidence indicates that viral hepatitis is sometimes associated with the production of extrahepatic tissue injury. Hepatitis B virus (HBV) infection is most commonly incriminated but non-type B hepatitis may also be involved. Three types of syndromes have been recognized. First, a serum sickness-like prodrome consisting of skin eruptions, urticaria and polyarthralgias or arthritis may occur from one to six weeks prior to the onset of hepatitis in 15 to 20 per cent of patients and usually disappears by the time the patient becomes jaundiced. There is extensive evidence that circulating immune complexes are responsible for these symptoms. Second, about 30 to 40 per cent of patients with typical polyarteritis nodosa have persistent hepatitis B surface antigenemia (HBs Ag). Circulating immune complexes composed of HBs Ag, antibody, and complement have been demonstrated together with deposits of immune complexes at sites of vascular injury. Third, an immune complex type of glomerulonephritis may occur following hepatitis B virus infection, usually in association with chronic active hepatitis. Thus there is impressive evidence that hepatitis viruses, especially HBV, may produce a variety of extrahepatic manifestations in which the mechanism of pathogenesis involves an immunologic process rather than direct viral invasion and cytopathogenicity.