Associated urological anomalies in children with unilateral renal agenesis

Unilateral renal agenesis has been noted in 1:1,000 autopsies. Recently an increased incidence of vesicoureteral reflux was reported in patients with a solitary kidney. We determined the incidence of associated renal abnormalities in children with unilateral renal agenesis.

We retrospectively reviewed 46 consecutive cases of unilateral renal agenesis diagnosed at our hospital between January 1985 and February 1998. Patient age at diagnosis ranged from newborn to 12.5 years (mean 2.8 years). There were 24 boys and 22 girls. The left kidney was absent in 27 patients and the right kidney was absent in the remaining 19. A total of 24 patients were evaluated for urinary tract infection and in the other 22 a solitary kidney was found during examination for congenital malformations, enuresis or abdominal pain. The diagnosis was made in all patients by abdominal ultrasound and confirmed by excretory urography, or diethylenetriaminepentaacetic acid or dimercapto-succinic acid scan. A voiding cystourethrogram was performed in 40 patients (87%).

Associated urological anomalies were present in 22 of the 46 patients (48%) with unilateral renal agenesis, including primary vesicoureteral reflux in 13 (28%), ureterovesical junction obstruction in 5 (11%), ureteropelvic junction obstruction in 3 (7%), and ureterovesical and ureteropelvic junction obstruction in 1 (2%). Of the 22 patients 14 (64%) underwent surgical intervention.

Nearly half of the patients with unilateral renal agenesis had associated urological anomalies. Vesicoureteral reflux was the most common associated anomaly and it was usually of high grade. Early recognition and treatment of urological anomalies in a patient with a solitary kidney are imperative to decrease the long-term risk of renal damage.