The coexistence of primary megaureter and reflux.

Primary megaureter is a common cause of obstruction of the urinary tract in children. Vesicoureteric reflux is a common lower-tract abnormality. The seemingly paradoxical coexistence of these entities was found to occur nine times over the 10-year period, 1973 to 1983 (in about 2800 children with reflux and about 75 children with primary megaureter). This coexistence should be suspected on voiding cystourethrography when the juxtavesical segment of the megaureter is normal in caliber, the refluxed contrast agent is diluted by urine that is trapped in the ureter, and drainage of refluxed contrast agent into the bladder is impeded. The diagnosis can be confirmed by excretory urography with a catheter draining the bladder to temporarily prevent the reflux. The surgical treatment consists of resection of the distal aperistaltic segment and reimplantation of the ureter.