Purpose: We determined the prevalence, anatomical variants and coexisting complications of duplex collecting systems in children with a history of UTI. Additionally, we compared the prevalence and severity of the coexisting anomalies with those found in single systems.
Materials and methods: We reviewed the records of children younger than 6 years who were evaluated following a first UTI during a 9-year period to identify those with duplex systems. Children without duplication anomalies comprised the control group.
Results: Of 774 evaluated children 63 (8%), more commonly females than males, had duplex systems. CDS were as common as IDS. VUR was the most commonly associated anomaly, with a higher prevalence in CDS (66%) and IDS (47%) compared to single systems (26%, p <0.0001 and p = 0.007, respectively). Ectopic ureterocele, which was the second most common associated anomaly, was found in 20% of the CDS but in none of the IDS or single systems. The occurrence of renal scarring was similar among CDS, IDS (13%) and single systems (10%). Poorly functioning pole moieties occurred more often in CDS (40%) compared to IDS (4%, p = 0.003), and were observed in none of the single systems. The resolution rate of reflux tended to be higher in IDS compared to CDS.
Conclusions: CDS were a common finding among children with UTI who had duplication anomalies. Although CDS and IDS were accompanied by VUR more often than were single systems, CDS were associated more often with severe VUR, other serious complications and poor renal function.