Abstract

The underlying etiology of antenatal hydronephrosis (ANH) is multifold, ranging from transient hydronephrosis in utero to clinically significant congenital anomalies of the kidney and urinary tract. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evalution depends on anteroposterior diameter (ADP) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obtruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patienst with ureteropelvic junction or ureterovesical junction obtruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obtructed renogram with differential renal function <35-40 or its subsequent decline.