Impact of Urinary Tract Infection on Progression of Renal Scars and Formation of New Scars in Patients with Primary Vesicoureteric Reflux.

Abstract

Primary vesicoureteric reflux (VUR) is a prevalent cause of end-stage renal failure in children. Scars on radionuclide imaging indicate irreparable damage to the growing kidneys. This study aims to determine whether a urinary tract infection (UTI) associated with primary VUR promotes the development of new renal scars or progression in the pre-existing ones. Children with primary VUR on continuous antibiotic prophylaxis at a tertiary teaching hospital's paediatric nephrourology clinic were observed prospectively. At recruitment, a renal cortical (dimercaptosuccinic acid [DMSA]) scan was done, and the children were followed up every 3 months. Breakthrough UTIs were documented, and follow-up DMSA scans were performed to document new scarring/grade advancement of existing scars in the renoureteric units (RUUs). Seventy-two RUUs in 36 patients were monitored. Fifty-four (75%) RUUs were exposed to VUR of different grades, and 46 (85.1%) had a UTI. On the DMSA scan, these showed new scar development in 10/18 (55%) RUUs and scar progression in 13/28 (46.4%) RUUs. Of the 8 RUUs with VUR and without UTI, new scars manifest in 4/5 (80%) and progressed in 1/3 (33%). On univariate analysis, there was no significant difference in the formation of new scars or scar advancement on the DMSA scan between RUU with VUR and UTI and those without UTI. There was a significant positive correlation between the scarring on DMSA scan and the grade of reflux (P < 0.001). Primary VUR patients had fresh or progressed scarring regardless of urinary infection. A higher VUR grade at presentation was a significant risk factor for scarring.