Ruptured coronary aneurysm and valvulitis in an infant with polyarteritis nodosa.

This report describes a 4-mth-old infant with polyarteritis nodosa who had a rapidly fatal course with the diagnosis ultimately being made at necropsy. The pathological lesions consisted of diffuse arterial disease with severe coronary involvement, and additional unusual features included a ruptured coronary artery aneurysm and a valvulitis of the mitral and aortic valves similar to that seen in rheumatic fever. The aetiology of polyarteritis is briefly summarised and the possibility of an immune reaction to foreign antigens, such as drugs or viruses, is considered.