Upper Urinary Tract Dilatation in Newborns and Infants

Abstract

The main dilemma in the investigation of upper urinary tract dilatation is to distinguish between dilatation with obstruction, dilatation with no obstruction, and dilatation associated with vesicoureteric reflux (VUR). At times the obstructive cause is obvious, e.g., duplex kidney with upper moiety dilatation due to a ureterocele or upper tract dilatation due to posterior urethral valves. However, the commonest abnormality found is unilateral renal pelvic dilatation (RPD), commonly termed ureteropelvic junction obstruction (UPJ). There is controversy concerning the investigations and the treatment of RPD in certain clinical situations. Renal cysts are uncommon in children, and when one is seen in the upper pole of a kidney the examiner should immediately suspect calyceal dilatation either in a single system or as part of an upper moiety of a duplex kidney. Whenever a transonic lesion is seen in the kidney one should always search for a dilated ureter, especially behind the bladder, and examine the bladder base with special care looking for a ureterocele.