Does every patient with prenatal hydronephrosis need voiding cystourethrography?

PURPOSE

Prenatal ultrasound has allowed early identification of urinary tract abnormalities that may require urological followup or early intervention. While all children with prenatal hydronephrosis should undergo ultrasound within the first few weeks of life, we believe that there is a subset of postnatal hydronephrosis for which voiding cystourethrography can be avoided if careful observation is continued.

MATERIALS AND METHODS

For 5 years 175 infants with a history of prenatal hydronephrosis were evaluated by ultrasound. Of 60 infants with less than Society for Fetal Urology grade II unilateral or bilateral hydronephrosis 44 underwent voiding cystourethrography as part of the early evaluation and 16 were observed without voiding cystourethrography. Four infants for whom we would routinely obtain voiding cystourethrography were excluded from study due to severe prenatal hydronephrosis, renal duplication, hydroureter, ipsilateral small or echogenic kidney and grade II or higher hydronephrosis.

RESULTS

Voiding cystourethrography was positive in 6 of the 40 infants (15%) with less than grade II hydronephrosis. Of these cases 3 had grade III or higher vesicoureteral reflux and 1 with high grade reflux required reimplantation. None of the 16 patients followed without voiding cystourethrography has required further evaluation or intervention. In all patients with negative or no voiding cystourethrography parenchyma was preserved and hydronephrosis stabilized or resolved.

CONCLUSIONS

Prenatal and postnatal ultrasound in infants should be used to guide further urological evaluation. Among infants with less than grade II hydronephrosis postnatally 15% had reflux on voiding cystourethrography, which is significantly higher than that reported among normal children (approximately 1%). However, none of the 16 infants observed without voiding cystourethrography on short-term antibiotic prophylaxis had deleterious renal events with 6 months to 4.5 years of followup. Therefore, we question the actual significance of the reflux detected in the first cohort of infants. Voiding cystourethrography can provide a definitive answer. However, we also believe that it is not absolutely mandatory based on the outcome in the observed group. With careful counseling and followup most patients with less than grade II hydronephrosis can be observed without urological sequela.