Ultrasonic indicators of ureteric reflux in the newborn.

There is controversy over the value of ultrasonic screening for detection of vesicoureteric reflux (VUR) in babies. We scanned 300 newborn babies and identified 53 with a dilated renal pelvis or other minor abnormalities. Eventually, 9 of these were investigated by voiding cystourethrography and 3 (5 kidneys) proved to have VUR exceeding grade II. In 3 babies the reason for cystourethrography was persistent renal pelvis dilation; in 3 it was urinary tract infection; and in 3 it was a new ultrasonic sign observed early in the series--ballooning of the renal pelvis during voiding. Whereas persistent dilation of the renal pelvis was a non-specific indicator (absent in 2 of the 5 affected kidneys and present in 5 of those unaffected), ballooning was consistently seen in all 5 affected renal pelvises. This sign, easily obtained in a baby who has been sleeping, deserves prospective assessment for its value in screening.