Vesicoureteral Reflux in Neonates with Hydronephrosis; Role of Imaging Tools

Objective: Neonatal Hydronephrosis is a common abnormality diagnosed ante- or postnatally. The aim of this study was to determine the prevalence and severity of vesicoureteral reflux (VUR) in neonates with antenatal or postnatal hydronephrosis and the value of ultrasonography as a noninvasive tool for VUR prediction. Methods: in a prospective study, 202 infants with neonatal hydronephrosis were studied. Two successive renal ultrasound examinations were performed at 1 and 4-6 weeks after birth in neonates with antenatal hydronephrosis or immediately after presentation. Voiding cystourethrography (VCUG) was performed in all infants. Findings: The incidence of VUR was 29.7%, of which 17.8% had severe (grade IV-V) reflux. 27% of 133 neonates with unilateral and 34.8% of 69 cases with bilateral hydronephrosis had VUR. Although a significant association was observed between severity of hydronephrosis and VUR, 5.9% of normal appearing and 7.8% of grade 1 hydronephrotic neonates had high-grade reflux. Conclusion: VUR was observed significantly in hydronephrotic neonates. A normal or mildly hydronephrotic urinary tract on ultrasound scan cannot exclude presence of severe VUR. We recommend performing VCUG in all hydronephrotic newborns.