title: 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.
authors.affiliation: Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Persutte
authors.forename: M
authors.initials: M
authors.lastname: Koyle
authors.forename: R R
authors.initials: RR
authors.lastname: Lenke
authors.forename: J
authors.initials: J
authors.lastname: Klas
authors.forename: C
authors.initials: C
authors.lastname: Ryan
authors.forename: J C
authors.initials: JC
authors.lastname: Hobbins
mesh_terms: D000293:Adolescent; D000328:Adult; D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D006869:Hydronephrosis / Q000151:congenital / Q000000981:diagnostic imaging / Q000601:surgery; D007231:Infant, Newborn; D007674:Kidney Diseases / Q000151:congenital / Q000000981:diagnostic imaging* / Q000601:surgery; D007682:Kidney Pelvis / Q000002:abnormalities / Q000000981:diagnostic imaging*; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D016284:Technetium Tc 99m Pentetate; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014567:Urography; D014718:Vesico-Ureteral Reflux / Q000151:congenital / Q000000981:diagnostic imaging / Q000601:surgery
chemical_list: D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate