Relapses of idiopathic diffuse crescentic glomerulonephritis without immune deposits: report of 6 cases.

Idiopathic diffuse crescentic glomerulonephritis without immune deposits is a variant of rapidly progressive glomerulonephritis which can account for up to 40% of crescentic nephritis. The prognosis may depend on both the severity of histological injury at presentation and the efficacy of treatment. Recent advances in therapy have improved the outlook further, and prolonged stable remissions with mild renal failure can occur which contrast with the previously common evolution towards end-stage renal failure within a few weeks. However, relapses in otherwise stable remission may be seen, and we describe a series of 6 acute relapses interrupting such prolonged remissions. The relapses were defined by clinical and histological means. This modification of the natural history of some crescentic glomerulonephritis may reflect new therapeutic strategies, and the relapses may reflect a cyclical nature to the disease evolution which was previously hidden by hemodialysis. The possibility of successive flares suggests that kidney biopsies should be repeated when a rapid deterioration of renal function occurs, since treatment such as high-dose steroids and/or plasma exchange can be again effective if started early.