Phenylbutazone-induced systemic vasculitis with crescentic glomerulonephritis.

Two patients had phenylbutazone-induced systemic vasculitis syndrome. Both presented with acute oliguric renal failure, and renal biopsies showed severe crescentic glomerulonephritis with marked interstitial inflammatory cell infiltration. Withdrawal of phenylbutazone and treatment with immunosuppressives and plasma exchange led to recovery of renal function in one case.