URINARY OBSTRUCTION CAUSES IRREVERSIBLE RENAL-FAILURE BY INDUCING CHRONIC TUBULOINTERSTITIAL NEPHRITIS

Obstruction of urinary tract is a frequent cause of transient renal dy sfunction, which, in the majority of cases, is reversible. Urinary obs truction can occasionally cause chronic renal failure, in spite of suc cessful relief of the obstruction. Sonographic and pathologic studies show renal atrophy, interstitial fibrosis, and interstitial inflammati on, which explain the loss of renal function. Herein, we report two ca ses of bilateral obstructive nephropathy due to prostatic hyperplasia, in which renal ultrasound demonstrated hydronephrosis and normal cort ical thickness. In both cases, the renal failure persisted even after urinary obstruction was relived by continuous catheter drainage. Renal biopsy showed that in each case the cause of the irreversible renal f ailure was chronic tubulointerstitial nephritis. It is concluded that renal biopsy can be of diagnostic, as well as prognostic value in obst ructive nephropathy, especially when relief of the obstruction is not followed by restoration of the renal function.