The duplex collecting system in girls with urinary tract infection: prevalence and significance.

The association between vesicoureteral reflux, parenchymal scarring, and urinary tract infection in children with nonduplicated collecting systems is well known, but similar data for children with duplex systems are sparse. The purpose of this study was to determine the prevalence of duplex anomalies in girls with a history of urinary tract infection and to compare the prevalence of associated reflux and parenchymal scarring to that found in girls with nonduplex systems. Voiding cystourethrograms and excretory urograms of 560 girls referred for evaluation of urinary tract infections were reviewed retrospectively. Duplex collecting systems (complete and partial) were found in 8%. Vesicoureteral reflux was seen in 69% of complete duplex systems and in 22% of partial duplex systems. Parenchymal scarring was evident in 17% of those girls with complete duplication and in 6% of those with incomplete duplication. The statistics for girls with partial duplication were very similar to those for girls with urinary tract infection and nonduplex systems. These data indicated that girls with partial duplex systems clinically appear similar to those girls with anatomically normal systems. Girls with complete duplex systems had a higher prevalence of vesicoureteral reflux and associated anomalies, indicating a need for closer follow-up and/or surgical intervention.