SIMULTANEOUS POSTINFECTIOUS GLOMERULONEPHRITIS AND THROMBOTIC MICROANGIOPATHY - A RENAL BIOPSY STUDY

The simultaneous occurrence of postinfectious glomerulonephritis and t hrombotic microangiopathy is described in renal biopsy specimens from three patients, Each presented with diverse manifestations: two patien ts had hypertension and acute renal failure, and in the third, it was unclear whether an atypical postinfectious glomerulonephritis or an at ypical thrombotic microangiopathy was present. All biopsy specimens di sclosed a combination of irregular granular complement and immunoglobu lin deposits in mesangial regions and capillary walls along with fibri n in a linear pattern in capillary walls by immunofluorescence. Light microscopy showed diffuse hypercellularity in some glomeruli, endothel ial cell swelling, luminal thrombi and mesangiolysis in others, and bo th types of changes in a third group, Ultrastructurally, subepithelial hump-shaped deposits coexisted with widened and lucent subendothelial spaces, Possible pathogenic mechanisms for the synchronous lesions in clude endothelial injury, perhaps triggered by infection and immunolog ic tissue damage. (C) 1998 by the National Kidney Foundation, Inc.