Urinary Tract Dilation

Urinary tract dilation (UTD), also commonly referred to as hydronephrosis, is a congenital anomaly detected prenatally. The term UTD is now used to describe all degrees of antenatal and postnatal dilation, superseding other terms like hydronephrosis, pelviectasis, caliectasis, and pelvicaliectasis. UTD denotes the dilation or enlargement of the renal pelvis and calyces and can be related to a spectrum of urologic pathologies collectively referred to as congenital anomalies of the kidney and urinary tract (CAKUT). These entities are associated with risk of chronic kidney disease (CKD) and are the main cause of End Stage Kidney Disease (ESKD) in children. UTD is a common form of presentation of CAKUT and commonly appears as an initial “sign” of obstructive uropathy [1]. Causes of antenatal UTD comprise obstructive and non-obstructive etiologies such as ureteropelvic junction (UPJ) obstruction, vesicoureteral reflux (VUR), lower urinary tract obstruction ([LUTO] posterior urethral valves, ureterocele, and urethral atresia), ectopic ureter, and idiopathic transient dilation [2]. The degree of dilation correlates with the presence of urologic disease and the need for surgery [3].