Skip Ribbon Commands
Skip to main content
Health Issues

Ureteropelvic Junction Obstruction

child upset stomach child upset stomach

What is a ureteropelvic junction (UPJ) obstruction?

Our kidneys work to filter waste out of our blood and make urine, which then drains into the bladder through tubes called ureters. When a ureter becomes blocked near the kidney, urine can build up inside the kidney and cause swelling (hydronephrosis).

About 1 in 1,000 children are born with a blocked UPJ. Over time, the blockage can prevent the kidney from doing its job and cause damage.

How do I know if my child has a UPJ obstruction?

Prenatal ultrasound exams sometimes can show a UPJ blockage before birth. In older children and adolescents, the blockage is found after the child gets a urinary tract infection. Other signs and symptoms of UPJ obstruction can include abdominal pain or soreness in their lower back and side. The pain may be vague, and the child may also get an upset stomach, nausea and vomiting.

How is a UPJ diagnosed?

Ultrasound is the main imaging study used to diagnose ureteropelvic junction (UPJ) obstruction. But sometimes, different imagining tests like a computed tomography (CT) scan or magnetic resonance imaging (MRI) done for other reasons reveal the blockage. A nuclear kidney scan (and sometimes a specific type of MRI) can show the doctor how well the kidney is functioning and how big the blockage is. In certain cases, a voiding cystourethrogram test is done to make sure that the swelling is not being caused by another condition called vesicoureteral reflux, a backwards flow of urine.

Why causes a UPJ?

When infants have a UPJ blockage, most often it's because they have an especially narrow ureter where it connects to the kidney. Children and adolescents may have the same situation but are more likely to have a blood vessel crossing the ureter that causes the blockage.

How is UPJ treated?

If a baby is born with a UPJ, doctors may monitor the blockage and any swelling with ultrasound exams. Sometimes, the condition will improve on its own as infants and young children outgrow it. However, if the blockage gets worse or if you child gets repeated infections, surgical repair of the UPJ (pyeloplasty) will be needed. But it is important to have close follow-up with your pediatric urologist, even if your child does not have any symptoms.

What if my child needs pyeloplasty surgery?

UPJ surgery involves removing the blocked or narrowed area of the ureter and rerouting it to let urine to travel through freely. There are different surgical techniques used for pyeloplasty, and the decision about which type is best for your child is best made with your pediatric urologist. Because every child is different, the type of surgery should be individualized. Surgery usually involves an overnight stay in the hospital. Recovery may take one to two weeks, but full recovery is to be expected after a month.

Additional Information from

Last Updated
Section on Urology (Copyright © 2018 American Academy of Pediatrics)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
Follow Us