Isolated renal scars without associated hypodysplasia predict recurrent urinary tract infections (UTI) but preserved kidney function after febrile UTI in childhood.

Introduction: Acquired renal scarring (RS) and congenital renal hypodysplasia (RHD) are risk factors for chronic kidney disease. Previous studies did not clearly differentiate between them regarding clinical outcomes following febrile UTI (fUTI).

Methods: We reviewed DMSA scans performed at Schneider’s Children Medical center between November 2007 to February 2011. Inclusion criteria were patients with at least one recorded fUTI prior to scan, performed at least four months post fUTI. Scan results were classified according to the presence of scars and/or dysplastic renal parenchyma. Outcomes included subsequent fUTI and last recorded serum creatinine.

Results: Of 100 reviewed scans, 66 patients met inclusion criteria, 48 (73%) were females. Median (IQR) age at scan was 2.1 (1.5, 4.4) years. Thirty- four (51.5%) patients had normal scans, 12 (18%) had only RS, 13 (20%) had only RHD and 7 (10.5%) had RS+RHD. Ten (15%) patients with vesicoureteral reflux required surgical intervention. Sixty- three (95.4%) patients had follow- up data at a mean of 9.3±3 years, 24 (38%) patients experienced recurrent fUTI [median (IQR) 2 (1, 5.5)]. Tendency for fUTI differed between groups (RS only: 91.6%; RS+RHD: 42.9%; RHD only: 25%; normal scan: 21.8%, p<0.001). On multivariate analysis, only RS predicted recurrent fUTI [OR 6.29 (1.57, 25.2)]. Two (3%) patients developed abnormal serum creatinine at last follow up, one had RHD and the other RS+RHD (but none in the RS only group).

Conclusions: Finding of RS following fUTI is a strong predictor of recurrent fUTI. Kidney function was preserved in patients with scars without RHD.