Posterior urethral valves: are neonatal imaging findings predictive of renal function during early childhood?

Background Obstructive renal dysplasia as observed on US is associated with posterior urethral valves and is regarded as predicting poor renal functional outcome. Objective To investigate whether any characteristic of urinary tract imaging at birth is predictive of renal function in children with prenatally diagnosed posterior urethral valves. Materials and methods We reviewed clinical data including renal function (at birth and up to 3 years of age) and clinical outcome (urinary infection, dialysis, renal transplantation). Imaging data included US (dilatation of the urinary tract, renal cortical echogenicity, signs of cystic dysplasia, urinoma) and cystourethrography findings (vesicoureteral reflux, bladder anomalies, presence of valves) from imaging performed directly after birth. Results We retrospectively studied 30 children. Three of the 30 (10%) were in renal failure by the age of 3 years. Twelve of 14 (85%) children with parenchymal anomalies (cortical hyperechogenicity or cystic changes) and 8/9 (89%) children with bilateral high-grade reflux had normal renal function at age 3 years. One child without cystic dysplasia or reflux had abnormal renal function from birth. None of the six children with urinoma developed renal failure by the age of 3 years. Conclusion Presence of cortical hyperechogenicity, cystic changes or bilateral reflux cannot be considered prognostic of renal failure by the age of 3 years.