ABSTRACT
Background Renal pelvic dilatation is one of the abnormalities detected antenatally by ultrasound scan (USS), incidence being around 0.5-1% of live births. In most children it is benign. Objectives To determine the local occurrence and outcomes of antenatally detected renal pelvic dilatation and to determine whether there is a sex difference in the incidence and outcomes Method The 18-20 weeks morphology scans of all live newborn babies delivered in the maternity ward of Hervey Bay hospital from 01/02/2008 to 30/09/2008 were retrospectively analysed. Infants with antenatally detected renal pelvic dilatation were followed up with 2 weeks postnatal USS. Infants with increasing pelvic dilatation or persistent moderate to severe dilatation were followed up with MCUG / MAG 3 scan. Results Total number of live births during the 8 month period was 695. There were 362 males and 333 females. There were 15 (2.2%) neonates (7 male, 8 female) with antenatally detected renal pelvic dilatation. Occurrence in males was 1.9% and females 2.4% (p =0.671). Five cases were bilateral and 10 unilateral. In unilateral cases, left side involvement was more common (60%). In bilateral cases left side involvement was more severe in 60%. There were 9 (60%) cases with mild dilatation, 4 (27%) with moderate dilatation and 2 (13%) with severe dilatation. Oligohydramnios, thickened bladder or dilated ureters were not detected in any of the cases. Caliectasis was detected in 2 infants (13.3%) who had severe dilatation in antenatal scan. Subsequent postnatal scan was completely normal in 6 (40%), improved in six (40%) and worse in three (20%). There were 4 cases with mild, 2 with moderate and 3 with severe dilatation. All infants with severe dilatation had caliectasis. MCUG was done in 3 infants but did not detect any abnormality or reflux. Antibiotic prophylaxis was stopped after normal MCUG. MAG 3 scan was done in 3 infants including one with normal MCUG and all three detected PUJ obstructions but none required surgery. All 3 infants with PUJ obstruction had either severe (2) or moderate (1) dilatation on antenatal scan and all 3 had severe dilatation on postnatal scan. Of these 3 infants with PUJ obstruction, 2 had caliectasis in antenatal scan and all 3 had caliectasis in the subsequent postnatal scan. Follow up period varied from 1 to 9 months. None developed symptomatic UTI during this period. Conclusions There were 2.2% neonates with antenatally detected renal pelvic dilatation. Outcome was satisfactory in 80% of cases. There was no significant sex difference in occurrence or outcome.