Multicystic dysplastic kidney: is an initial voiding cystourethrogram necessary?

INTRODUCTION: Traditionally, a voiding cystourethrogram (VCUG) has been obtained in patients diagnosed with multicystic dysplastic kidney (MCDK) because of published vesicoureteral reflux (VUR) rates between 10%-20%. However, with the diagnosis and treatment of low grade VUR undergoing significant changes, we questioned the utility of obtaining a VCUG in healthy patients with a MCDK. We reviewed our experience to see how many of the patients with documented VUR required surgical intervention.

MATERIALS AND METHODS: We performed a retrospective review of children diagnosed with unilateral MCDK from 2002 to 2012 who also underwent a VCUG.

RESULTS: A total of 133 patients met our inclusion criteria. VUR was identified in 23 (17.3%) children. Four patients underwent ureteral reimplant (3.0%). Indications for surgical therapy included breakthrough urinary tract infections (2 patients), evidence of dysplasia/scarring (1 patient) and non-resolving reflux (1 patient). All patients with a history of VUR who are toilet trained, regardless of the grade or treatment, are currently being followed off antibiotic prophylaxis. To date, none have had a febrile urinary tract infection (UTI) since cessation of prophylactic antibiotics. Hydronephrosis in the contralateral kidney was not predictive of VUR (p = 0.99).

CONCLUSION: Routine VCUG in healthy children diagnosed with unilateral MCDK may not be warranted given the low incidence of clinically significant VUR. If a more conservative strategy is preferred, routine VCUG may be withheld in those children without normal kidney hydronephrosis and considered in patients with normal kidney hydronephrosis. If a VCUG is not performed the family should be instructed in signs and symptoms of urinary tract infection.