Clinical Characteristics and Outcome of Fetal Hydronephrosis

Lim, Dae Jung; Lee, Hyun Moo; Choi, Hwang

Abstract

PURPOSE: We performed a retrospective study to determine the clinical characteristics and outcome of fetal hydronephrosis.
MATERIALS AND METHODS
The records of the children diagnosed with fetal hydronephrosis between 1990 and 2001 were retrospectively analyzed. In the postnatal follow-up period, the children were followed by sequential ultrasonography and urinalysis. Diuretic renal scanning and voiding cystourethrography were performed in selected cases. The clinical characteristics and outcome were evaluated and compared to the degree of hydronephrosis.
RESULTS
The study comprised 341 children with 427 dilated kidneys. Mild (Grade 1), moderate(Grade 2 or 3) and severe(Grade 4) hydronephrosis were present in 21.8%, 60.4% and 17.8% respectively. Hydronephrosis resolved spontaneously in 126(29.5%) kidneys, including 52.7% of mild and 2.6% of severe hydronephrosis. Mean interval to spontaneous resolution was 1.39(+/-1.41, SD) years. Dilatation of the renal pelvis was caused by primary ureteropelvic junction obstruction in 65.6%, multicystic kidney in 9.4%, vesicoureteral reflux in 7.0%, duplex system in 5.4%, ureterovesical junction obstruction in 4.0%, and posterior urethral valves in 3.0%. Surgery was performed in 174 kidneys, consisting of pyeloplasty in 105, ureteroneocystostomy in 23, transurethral incision in 11, and nephrectomy in 9. Most patients had initially high-grade hydronephrosis (p<0.05).
CONCLUSIONS
Mild hydronephrosis appears to be relatively benign, and in most cases dilatation improves with time with surgical intervention thereby not required. On the other hand, moderate or severe hydronephrosis often RESULTS in a significantly poorer outcome and requires surgical intervention, and hence closer follow-up both antenatally and postnatally.