New renal scars in children with urinary tract infections, vesicoureteral reflux and voiding dysfunction: a prospective evaluation.

PURPOSE: Established renal scarring represents areas of the kidney that imaging reveals to be damaged at presentation for medical management of urinary tract infection. New renal scarring represents new renal damage in parts of the kidney that imaging reveals to be normal at presentation. We attempted to characterize patients in whom new renal scars developed while they were under our care.

MATERIALS AND METHODS: In 1988 a data base was started to identify patients with new renal scarring. All patients presenting with urinary tract infections were enrolled. Our data base has 250 possible fields per event with multiple events per patient. More than 2,100 patients have been enrolled to date. All patients with pyelonephritis, defined as a febrile urinary tract infection with flank pain and tenderness, and all with reflux underwent dimercapto-succinic acid (DMSA) scan at least 4 months after presenting with infection to assess established renal scars. New renal scars were identified when new renal defects were demonstrated on a second DMSA scan.

RESULTS: In our data base there are 1,426 patients with urinary tract infections, 685 (46%) with pyelonephritis and 1,062 (74.5%) with vesicoureteral reflux, including 558 found to have bilateral vesicoureteral reflux and 504 diagnosed with unilateral reflux. A history of daytime urinary incontinence was noted in 538 patients (37.7%), 192 (13.5%) had established scars at initial presentation and in 31 (2.1%) new renal scars developed while they were under our care, including 30 with established scars as well. Of the 25 patients in whom new renal scars developed while on medical therapy 11 underwent surgery. In 6 patients with dysfunctional voiding who were receiving medical treatment renal scars developed postoperatively. Surgery was performed in 17 of the 31 patients and 24 (77%) with new renal scars had a history of dysfunctional voiding.

CONCLUSIONS: Previous characterizations of patients with new renal scars have relied on excretory urography for assessing renal architecture and ignored voiding patterns of the children affected. Using the DMSA scan we identified 31 children with reflux, urinary tract infection and dysfunctional voiding in whom new renal scars developed while they were under our care.