ureteropelvic junction obstruction
Blockage at the connection between the renal pelvis and ureter, causing hydronephrosis.
Full Definition
Ureteropelvic junction (UPJ) obstruction is the most common cause of prenatally detected hydronephrosis and represents a functional or anatomical narrowing at the junction between the renal pelvis and proximal ureter. This condition can be intrinsic, due to abnormal muscle development or fibrotic tissue, or extrinsic, caused by crossing blood vessels or other external compression. UPJ obstruction typically presents with hydronephrosis on prenatal ultrasound or may manifest later with flank pain, urinary tract infections, or kidney stones. The diagnosis is confirmed through nuclear medicine studies (MAG3 renogram) that assess both kidney function and drainage. Treatment ranges from observation in cases with good kidney function to surgical repair (pyeloplasty) for cases with deteriorating function or symptoms.
Usage
Usage note: Can be abbreviated as UPJ obstruction after first use. Junction should not be abbreviated in formal documentation.
In Context
- "MAG3 renogram confirmed ureteropelvic junction obstruction with delayed drainage from the left kidney." — Nuclear medicine report
- "Laparoscopic pyeloplasty was performed to correct the patient's symptomatic ureteropelvic junction obstruction." — Operative report