Prenatal hydronephrosis: early evaluation.

PURPOSE OF REVIEW Fetal hydronephrosis is the most common anomaly detected on antenatal ultrasound examination, and its significance and management remain controversial. This review aims to address the early postnatal evaluation of the child with prenatally diagnosed hydronephrosis. RECENT FINDINGS The risk of significant urological pathology increases with the severity of prenatal hydronephrosis. The most common underlying conditions are ureteropelvic junction obstruction and vesicoureteral reflux. The use of postnatal ultrasonograpy in all patients with a history of any degree of prenatal hydronephrosis is routine, but ascertaining which patients require postnatal evaluation with a voiding cystourethrogram to investigate for vesicoureteral reflux remains controversial. Mild cases are the most controversial as the risk of pathology is lessened, however the risk of vesicoureteral reflux and consequent febrile urinary tract infection may be significant. Early postnatal evaluation of all children with a history of prenatal hydronephrosis with a voiding cystourethrogram may reduce this risk. No prospective randomized clinical trials are available, however, to adequately address the question of which patients require postnatal evaluation. SUMMARY The postnatal management of prenatal hydronephrosis remains controversial. Sufficient data are lacking to inform patient risk stratification. Therefore, early postnatal evaluation of children with a history of any degree of prenatal hydronephrosis with an ultrasound and voiding cystourethrogram is reasonable and may reduce the risk of febrile urinary tract infection.