Renal papillary necrosis associated with Wegener's granulomatosis.

Review of the kidneys from 23 cases of Wegener's granulomatosis revealed necrosis of the renal papillae in five (21.7 per cent). These cases took a fulminant course of the disease consistent with the classic description of Wegener's granulomatosis, prevalence in the older age group, and rapid deterioration of renal function. Morphologic examination of the kidneys uniformly disclosed a variety of lesions in the blood vessels supplying the renal papilla. The most conspicuous was the widely distributed glomerular lesion represented by thrombotic and necrotic occlusion of capillary loops and crescent formation. A medullary interstitial lesion characterized by fibrinoid necrosis of the vasa recta was invariably found in the outer portion of the necrotic papilla. In addition, acute segmental and diffuse necrosis and occlusion by thrombosis were identified in the branches of spiral arteries in the adjoining papilla. The results provide an anatomic basis for the assumption that papillary ischemia due to impairment of the dual blood supply from the vasa recta and the calyceal arteries is the essential factor in papillary necrosis.