Age of Spontaneous Regression of Congenital Hydronephrosis in Children

Kim, Ki Kyung; Oh, Chang Hee

Abstract

PURPOSE
It is difficult to anticipate the prognosis of hydronephrotic kidneys in children. Therefore, the progress of hydronephrosis detected after birth were investigated prospectively according to the ultrasonographic findings.
MATERIALS AND METHODS
The study included 36 patients (51 kidneys) who were diagnosed with hydronephrosis caused by a ureteropelvic junction stricture. The patients' age ranged from newborn to 9.8 years (mean, 10.2 months). There were 26 boys (72.2%) and 10 girls (27.8%). 4 cases (11.1%) were in the right kidneys, 17 cases (47.2%) were in the left kidneys and 15 cases (41.7%) in both. The patients were divided into three groups; the spontaneous regression group (SR), the no change group (NC) and the operation group (OP). The average age of each group were 1.5 months, 2.4 months, and 53 months, respcetively. Regression was defined as a decrease in the anteroposterior diameter (APD) of less than 4mm or more than 50% of the initial diameter during the follow up period.
RESULTS
The SR group had 21 cases (27 kidneys, 52.9%). The NC group included 10 cases (14 kidneys, 27.5%) and the OP group had 8 cases (10 kidneys, 19.6%). In the SR group (N=27 kidneys), the APDs of the renal pelvis decreased abruptly from 8.6mm to 1.3mm by the average age of 5.9 months. However, in NC group (N=14 kidneys), there was no significant interval change (from mean 10.1mm to 10.3mm) in the APDs of the renal pelvis by 10.4 months of average age.
CONCLUSIONS
The congenital hydronephrosis, which was caused by a ureteropelvic junction stricture and was identified after birth, regressed spontaneously in 52.9% of cases and it had usually occurred by 5.9 months of age. Therefore, it is supposed that age is an important factor in the follow-up and management of hydronephrosis in children.