Mild pyelectasis ascertained with prenatal ultrasonography is pediatrically significant

Abstract

Isolated 'mild renal collecting system dilatation' (mild pyelectasis) is a common prenatal sonographic finding. An association between mild pyelectasis and fetal aneuploidy has been established, but in the absence of a concomitant anomaly, mild pyelectasis is usually regarded as benign and of no clinical consequence, and follow-up is often not obtained after the initial ascertainment. To test this, we investigated the relationship between mild pyelectasis and (1) progression to hydronephrosis; (2) postnatal vesicoureteral reflux (VUR); and (3) postnatal surgery. Between 1 January 1992 and 1 January 1995, we performed 453 prenatal sonographic examinations of 306 patients with mild fetal pyelectasis and no other anomalies. During the course of a routine sonographic examination, we performed a detailed evaluation of the fetal genitourinary tract, Mild pyelectasis was defined as a pelvocalyceal fluid-filled space with the smallest of two transverse perpendicular sonographic measurements of > or = 4 mm and < 10 mm. Hydronephrosis was defined similarly, but with a measurement of > or = 10 mm. Postnatal urological assessment was obtained with routine renal ultrasonography, and voiding cystourethrography (VCUG), measurement of 99mTc-labelled diethylenetriamine pentaacetic acid (DPTA) mercaptacetyltriglycerine (MAG3), and intravenous pyelogram, as necessary. After exclusion criteria were applied, 294 (96%) patients with isolated fetal pyelectasis were considered. A total of 251 (82%) of these were followed with ultrasonography prenatally and during the postnatal period. Two or more prenatal examinations were carried out in 129 patients (51%) and in 35 (27%) of these cases the biometry progressed to frank hydronephrosis (> 10 mm). In only six (5%) of the cases followed prenatally did the measurement diminish to < 4 mm. We found a greater variability in prenatal renal biometry throughout gestation in infants found to have VUR, when compared with those who had no VUR. On postnatal follow-up, 84 patients had VCUG. Sixteen of these patients (6% of all patients [16/251] and 19% [16/84] of those who had the test) were found to have an abnormal finding. Whereas the prenatal appearance of mild pyelectasis improved in only a small number of cases, we found that it progressed to hydronephrosis in 27% of cases. Postnatal evaluation found VUR to be common in apparent uncomplicated mild prenatal pyelectasis. Although postnatal surgery was necessary in only a small number of cases, surgical intervention was necessary in 33% (four of 12) of those with VUR.

Antenatal and postnatal ultrasound in the evaluation of the risk of vesicoureteral reflux

“…The incidence of VUR in normal children is estimated at 9% [19], while studies that have included VCUG at birth estimate that VUR varies from 4 to 30% in children with ANH [15,20]. Many studies have demonstrated a lack of correlation between the degree of pelvic dilatation and the risk of VUR, leading many authors to recommend performing a VCUG on all children with ANH regardless of the degree of postnatal dilatation [5,15,21,22].…”

Mild Dilatation of Renal Pelvis in Term Neonates with Urinary Tract Infection

“…They suggested that values between 5 and 10 mm found in the second trimester of pregnancy should be confirmed by a repeat scan in the third trimester and that postnatal investigations should be limited to those with antenatal pyelectasis of 110 mm. Persutte et al [12] defined fetal mild pyelectasis when transverse ultrasonographic measurements of 64 to !10 mm were found. They concluded that prenatal appearance of mild pyelectasis improved in only a small number of their cases (5%) and that it progressed to hydronephrosis in 27%.…”

Prenatal diagnosis for paediatricians

“…Pyelectasis should always be followed up with a renal ultrasound in the first week of life after feeds have been established. If there is evidence of reflux, then a urology consult should be considered (45,46). Echogenic bowel: As well as being associated with chromosomal anomalies, echogenic bowel can be associated with viral infections and cystic fibrosis (CF) (47,48).…”