UP junction obstruction
Key points
- Ureteropelvic junction (UPJ) obstruction involves a blockage in the area where a ureter, one of the tubes that carries urine from the kidney to the bladder, attaches to the part of the kidney known as the renal pelvis.
- UPJ obstruction is generally a congenital (present from before birth) condition caused by narrowing of the connection between the ureter and the renal pelvis, which is part of the kidney.
- Signs and tests Maternal pregnancy ultrasound may show hydronephrosis in the fetus.
- Surgical correction of the obstruction allows urine to flow normally.
Alternative names
Ureteropelvic junction obstruction; UPJ obstruction; Obstruction of the ureteropelvic junction
Definition
Ureteropelvic junction (UPJ) obstruction involves a blockage in the area where a ureter, one of the tubes that carries urine from the kidney to the bladder, attaches to the part of the kidney known as the renal pelvis.
Causes, incidence, and risk factors
UPJ obstruction is generally a congenital (present from before birth) condition caused by narrowing of the connection between the ureter and the renal pelvis, which is part of the kidney. This blockage causes urine to build up in the renal pelvis, damaging the kidney.
UPJ obstruction is the most frequently diagnosed cause of urinary obstruction in children. It is now commonly diagnosed during prenatal ultrasound studies that show a dilated renal pelvis or a condition called hydronephrosis.
When recognized before the baby is born, UPJ obstruction may require surgical correction in the first few days after birth. Less severe cases may not require surgery until later in life, and some cases do not require surgery at all.
UPJ obstruction may be recognized after birth when an abdominal mass is found on examination, or if the infant develops a Urinary tract infection associated with fever. Back pain and blood in the urine may also be signs of UPJ obstruction.
Symptoms
- Back or flank pain
- Urinary tract infection with fever
- Bloody urine (hematuria)
- Lump in the abdomen (abdominal mass)
Signs and tests
Maternal pregnancy ultrasound may show hydronephrosis in the fetus.
Tests after birth may include:
- Creatinine clearance
- BUN
- Electrolytes
- IVP
- Nuclear scan of kidneys
- Voiding cystourethrogram
Treatment
Surgical correction of the obstruction allows urine to flow normally. Open surgery is usually performed in infants, although adults may be treated with less-invasive procedures:
Frequently asked questions
What is UP junction obstruction?
Ureteropelvic junction (UPJ) obstruction involves a blockage in the area where a ureter, one of the tubes that carries urine from the kidney to the bladder, attaches to the part of the kidney known as the renal pelvis.
What are the risk factors for UP junction obstruction?
UPJ obstruction is generally a congenital (present from before birth) condition caused by narrowing of the connection between the ureter and the renal pelvis, which is part of the kidney. This blockage causes urine to build up in the renal pelvis, damaging the kidney. UPJ obstruction is the most frequently diagnosed cause of urinary obstruction in children. It is now commonly diagnosed during prenatal ultrasound studies that show a dilated renal pelvis or a condition called hydronephrosis. When recognized before the baby is born, UPJ obstruction may require surgical correction in the first few days after birth.
What are the symptoms of UP junction obstruction?
- Back or flank pain
- Urinary tract infection with fever
- Bloody urine (hematuria)
- Lump in the abdomen (abdominal mass) Signs and tests Maternal pregnancy ultrasound may show hydronephrosis in the fetus. Tests after birth may include:
- Creatinine clearance
- BUN
- Electrolytes
- IVP
- Nuclear scan of kidneys
- Voiding cystourethrogram
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.