Risk of renal scarring in vesicoureteral reflux detected either antenatally or during the neonatal period

Objectives. To evaluate both the demographic features and the renal outcome of fetal vesicoureteral reflux (VUR), two well-defined populations were analyzed: those with hydronephrosis detected by obstetric ultrasonography, and neonates diagnosed after developing their first urinary tract infection within the first 4 postnatal weeks. Methods. Twenty-one neonates with antenatally detected VUR were compared with 30 patients with neonatally detected symptomatic disease. The mode of presentation, fate of reflux, and renal outcome were analyzed. Results. Significantly more bilateral dilating VUR was found in postnatally versus antenatally diagnosed patients (53% versus 29%; P = 0.05). Fourteen percent presented with congenital renal dysplasia. No difference was,found in the incidence of congenital dysplasia between the two groups. Focal renal scars developed during follow-up in 19% of renal units. New scars were observed in dilating VUR only, especially in grades 4 and 5 (P <0.05), and these were exclusively in the postnatal patient group (P <0.005). Conclusions. Several demographic features of fetal VUR differ, depending on whether detected antenatally or postnatally. The incidence of bilateral dilating VUR was greater in postnatally detected cases, suggesting a more severe manifestation of the disease. Renal injury occurred in an appreciable number of renal units. The damage may be of congenital origin or may be acquired secondary to urinary tract infection. The risk of acquired renal scarring is particularly significant if dilating VUR is not detected until neonatally after the first urinary tract infection. (C) 2003 Elsevier Inc.