Radiologic recognition of extrahepatic manifestations of hepatitis B antigenemia.

Extrahepatic manifestations due to an immunologic response to a surface antigen of hepatitis B virus have been identified. These include a serum sicknesslike syndrome and a necrotizing vasculitis. The latter is far more important and in indistinguishable histologically from nonhepatitis related polyarteritis. At least 90 cases have been reported in the decade since 1970, and five are added here. The necrotizing vasculitis syndrome results from fibrinoid necrosis and inflammation of small and medium-sized arterial walls recognizable angiographically by arterial microaneurysms and often by visceral infarction and hemorrhage. Renal failure is common and often associated with pulmonary edema. Gastrointestinal symptoms are a prominent feature due to bowel ischemia. Infarction and perforation are significant causes of morbidity and mortality. Necrotizing vasculitis is also one cause of pancreatitis and of cholecystitis. Plain films, contrast studies, computed tomography, and sonography have been shown to be useful in the recognition of these complications.