Rapidly progressive glomerulonephritis. A clinical and pathologic study.

Twenty-nine cases of rapidly progressive glomerulonephritis were reviewed. In all cases there was less than three months between the onset of renal symptoms and renal biopsy. The serum creatinine was greater than 2.5 mg/100 ml at the time of biopsy, and the histology showed a 50 per cent or greater incidence of crescents in the glomeruli. Infectious or febrile episodes were present in 21 cases, microscopic hematuria was noted in 15 and proteinuria exceeding 2.5 g/24 hours in eight. Oliguria less than 500 ml/24 hours was present in 20 cases and dialysis was required in 22. In 10 cases there was sustained improvement; in the remainder the disease progressed or the patient died. The prognosis was related to the number and size of the glomerular crescents. Histologically cases fell into two main groups, one with predominantly extracapillary proliferation and the other with endo- and extracapillary proliferation. In the first group the disease was histologically and clinically more severe, and Immunofluorescence histology was heterogeneous and often non-specific except for three cases in which there were linear immunoglobulin deposits. In the second group the lesions were less severe and immunoglobulin deposits were common. Electron microscopy in 14 cases was confirmatory, and also demonstrated capillary rupture and necrosis of podocytes in some loops. Transition from group I to group II was observed in serial biopsy specimens in one case. The histologic and immunofluorescent heterogeneity suggest that rapidly progressive glomerulonephritis is the end result of several different pathogenetic mechanisms.