NEW ORLEANS, LA USA (UroToday.com) - The role of voiding cystourethrogram (VCUG) as a screening tool for vesicoureteral reflux (VUR) in the setting of febrile urinary tract infections, sibling reflux, and mild prenatal hydronephrosis has recently been a controversial subject. Posterior urethral valves (PUV) are a rare but important cause of congenital hydronephrosis that can have disastrous effects on renal development and bladder function if undiagnosed. Thus, it is common practice to order a screening VCUG for valves in any newborn male infant with bilateral hydronephrosis, regardless of grade. Dr. Vemulakonda and her colleagues set out to identify which infants would most benefit from screening VCUG for PUV. They hypothesized that infants with mild hydronephrosis (SFU grade 2) would have a low risk for PUV.
The authors have prospectively collected data since 2012 on patients with congenital hydronephrosis. They analyzed a cohort of male infants with bilateral hydronephrosis on initial postnatal US who ultimately underwent VCUG. Infants that were prenatally diagnosed with PUV were excluded.
Of the 82 male infants with bilateral hydronephrosis, 6 were ultimately diagnosed with PUV (7.3%) on VCUG. The valves were subsequently confirmed at the time of surgery. Half of these patients had SFU grade 2 bilateral hydronephrosis, and the other half had at least one side with SFU grade 3 or higher. Thus, the authors concluded that the severity of hydronephrosis does not correlate with the likelihood of valves. During the question and answer session, Dr. Vemulakonda revealed that there was also no association with the presence or absence of a dilated ureter.
Clearly, this series reflects a very small cohort of patients. However, even though the number needed to treat with a VCUG in order to diagnose PUV is large, the consequences of a missed diagnosis outweigh the risks and inconvenience of the test. We are lacking more specific predictors of disease which would allow us to narrow the population that are subjected to VCUG at this time.
Presented by Vijaya Vemulakonda at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
University of Colorado, Aurora, CO USA
Reported by Michaella M. Prasad, MD (Medical University of South Carolina, Charleston, SC USA), medical writer for UroToday.com