Clinical course of prenatally-detected hydronephrosis: Focus on ureteropelvic junction obstruction

Abstract

Purpose: The diagnosis and treatment of prenatally-diagnosed hydronephrosis remain controversial. We have conducted a retrospective study to examine the clinical characteristics and course of prenatally-diagnosed hydronephrosis, especially when in the presence of ureteropelvic junction obstruction (UPJO). Materials and Methods: Among all pediatric patients diagnosed with hydronephrosis by prenatal ultrasonography between September 2002 and June 2008, the study was performed on 103 patients (126 renal units), and the mean follow-up period was 19.2 months (range, 6-24 months). Ultrasonography was performed 2-3 days after birth, and after 1, 3, 6, and 12 months, and annually thereafter. Hydronephrosis was graded according to the Society for Fetal Urology (SFU) classification guidelines. Results: On ultrasonography performed 2-3 days after birth hydronephrosis was graded as follows: grade 1, 45 (35.7%); grade 2, 49 (38.9%); grade 3, 23 (18.3%); and grade 4, 9 (7.1%) renal units. In cases with UPJO complete improvement of hydronephrosis was detected in 16 renal units (40%); the renal units and rate of complete improvement in grades 1, 2, 3, and 4 were 12 (75%), 3 (17.6%), 1 (16.7%), and 0 (0%), respectively. The anticipated times of complete improvement of hydronephrosis in UPJO grades 1, 2, and 3 were 22.0, 31.3, and 50.4 months, respectively. Conclusions: In UPJO, the possibility of improvement of hydronephrosis lower than grade 2 was high, and thus follow-up for approximately 30 months may be needed. In patients with hydronephrosis > grade 3, the rate of improvement was low, thus compulsive follow-up is required.