Abnormal contralateral kidney in unilateral multicystic dysplastic kidney disease.

We performed a retrospective study of infants with unilateral multicystic dysplastic kidney (MCDK) in order to investigate the associated urological abnormalities. We examined the records of seven patients, in five of whom a diagnosis had been made prenatally using ultrasonography. Our investigation focused on the associated urological abnormalities, particularly on the contralateral side, and the results of voiding cystourethrography (VCUG). Four of the seven patients (57%) had urological abnormalities other than MCDK: three exhibited vesicoureteral reflux (VUR) of the contralateral side including one patient who also had an ipsilateral ectopic ureter, and the fourth patient had a ureterocele of the ipsilateral side. The results indicate that contralateral VUR, was the most common abnormality associated with MCDK. Two infants had high-grade VUR and underwent anti-reflux surgery soon after the diagnosis. Both have remained free of recurrent urinary tract infection.