Pediatric Radiology > Genitorinary > Hydronephrosis > Ureteropelvic Junction Obstruction

Ureteropelvic junction obstruction

Ureteropelvic junction obstruction (UPJ) is the most common anomaly of the GU tract. UPJ obstruction may be due to intrinsic causes from a defect in the musculature of the ureter or less commonly from extrinsic causes like a crossing renal vessel. UPJ is more common on the left but is frequently bilateral (20%). UPJ is evaluated with a nuclear medicine renal scan. If the renal function is severely impaired, the UPJ may be surgically repaired.
UPJ obstruction resulting in severe hydronephrosis as demonstrated on ultrasound.