Antenatal renal pelvic dilatation; the long-term outlook

AimThe purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is ≥ 10 mm or if there is calyceal or ureteric dilatation.)Material and methodsData were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of ≥ 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2–8 years.ResultsComplete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10mm. At 28–33 weeks gestation the risk varied from 5% at 5 mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy.ConclusionThe present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.