The area where the kidneys and ureters meet is called the ureteropelvic junction (UPJ). When this area forms abnormally during fetal development, it can cause a blockage—a congenital condition known as ureteropelvic junction obstruction (UPJ) obstruction. It occurs only once out of every 1,500 births.
In a healthy body, the kidneys filter the impurities in our blood and flush waste into urine. Urine flows into renal calyces, which are collecting areas for urine located in the kidneys. From there, urine drains into the renal pelvis and then the ureter. When this area is obstructed, urine cannot flow normally. This obstruction can cause serious damage to the affected kidney.
UPJ obstructions typically occur on one side of the body—usually the left side. Most blockages are minor and resolve on their own over time; only 15 – 20% of babies affected by this condition undergo surgical repair.
Diagnosis of Ureteropelvic Junction Obstruction
Children are typically diagnosed with UPJ obstruction after a prenatal ultrasound shows swelling in one of the kidneys—a secondary condition called hydronephrosis that happens in 1- 5 percent of all pregnancies. Once these babies are born, pediatric urologists at Riley at IU Health follow them closely with serial ultrasounds to see if the swelling subsides. Depending on their progress, we may also run other tests to fully assess their anatomy. Among them are:
- Blood tests. Your child's doctor will perform a blood test to measure kidney function and see how well infants excrete creatinine—a waste product that results from the kidneys doing their work..
- Voiding cystourethrogram (VCUG). In this test, contrast dye is injected into a bladder catheter and allows the doctor to see any vesicoureteral reflux—the amount of urine that backs up into the kidneys.
- Mercaptoacetyltriglycine (MAG3) renal scan. This diagnostic nuclear medicine test allows the doctor to see his/her kidneys and learn more about how they are functioning.
- Renal scan. This is a nuclear scan to check kidney function and the ability of the kidneys to drain.
Once these tests are done, we can begin planning treatment for any obstructions.
Treatments
Treatments
The degree of swelling noticed during fetal development is a good predictor of which babies will need surgical treatment after they are born. Surgery is only necessary if swelling does not decrease or if further tests show the kidneys are not functioning as they should. The age at which we encourage surgery varies based on each child’s progress. Some children may have surgery during the first few months of life; others may not need it until they are 2 or 3 years old.
An open or robotic surgery repairs the tube that drains the kidney (the ureter) by removing the part that does not allow proper drainage. Surgeons use healthy tissue from the body to create a normal funnel. This surgery has a 98 percent success rate. We continue to follow these children after surgery with routine ultrasound, but most never have another problem with the urinary tract system afterwards.
Another form of obstruction—symptomatic ureteropelvic junction obstruction––can occur in older kids and even adults. This version of UPJ is usually caused by a congenital condition that was too mild to be detected during fetal or newborn development; it can also stem from a blood vessel that crosses the ureteropelvic junction, causing occasional blockage. It is diagnosed after a child complains of side pain, nausea and vomiting and diagnostic imaging shows hydronephrosis. These children always need surgery and have similar success rates to those of younger children and babies after they are treated.
Key Points to Remember
Key Points to Remember
Some babies are born with a blockage in the area between the kidneys and the ureters. Physicians call this abnormality ureteropelvic junction obstruction (UPJ).
- UPJ is often detected during pregnancy when prenatal ultrasound reveals swelling in one of the kidneys.
- At birth, children who show symptoms of UPJ will be closely monitored to see whether the swelling in their kidneys subsides and determine how well the kidneys function.
- In some cases, older children can develop another form of this congenital condition, usually because their condition at birth was so mild that it could not be detected until later.
- Most children born with UPJ outgrow their condition without any treatment, but one out of every 1,000 newborns will eventually need surgical treatment.
- Most babies and very young children who require surgery have the operation performed through a small incision on their side, while older children and young adults are candidates for robotic-assisted surgery. This is an innovative, minimally invasive surgical technique that uses very small tools to perform complex surgery inside the body.
Support Services & Resources
Support Services & Resources
This patient education resource is published by the American Urological Association to offer information about urological conditions such as UPJ obstruction.
The U.S. National Library of Medicine shares public health information on thousands of conditions, including UPJ obstruction.
Ureteropelvic Junction (UPJ) Obstruction Research
Ureteropelvic Junction (UPJ) Obstruction Research
Pediatric urologists at Riley at IU Health have a grant from the National Institutes of Health to compare robotic surgery with open techniques for repairing ureteropelvic junction obstruction. They are studying any differences between recovery times, length of hospital stays and issues related to pain management.