Ureteropelvic junction obstruction is a blockage in the area that connects the renal pelvis (part of the kidney) to one of the tubes (ureters) that move urine to the bladder. Ureteropelvic junction obstruction generally occurs when a baby is still growing in the womb. This is called a congenital condition (present from birth).
What is Causes Ureteropelvic Junction Obstruction?
Most of the time, the blockage is caused when the connection between the ureter and the renal pelvis does not develop normally and causes urine to build up, possibly damaging the kidney.
The condition can also be caused when a blood vessel is located in the wrong position over the ureter, causing a kink in the ureter. In older children and adults, ureteropelvic junction obstruction can be due to scar tissue, infection, previous treatments for a blockage, or kidney stones.
Ureteropelvic junction obstruction is the most frequently diagnosed cause of urinary obstruction in children. It is now commonly diagnosed during prenatal ultrasound studies. In some cases, the condition isn't seen until after birth. Children may have an abdominal mass, urinary tract infection, or pain in the stomach or side.
Symptoms of Ureteropelvic Junction Obstruction
There may not be any symptoms. When symptoms occur, they may include:
- Abdominal, back, or flank pain (pain in the side)
- Bloody urine (hematuria)
- Lump in the abdomen (abdominal mass)
- Urinary tract infection (may include a kidney infection, where there is fever)
- Poor growth in infants (failure to thrive)
Exams and Tests
An ultrasound during pregnancy may reveal kidney problems in an unborn baby.
Tests after birth may include:
- Kidney ultrasound study – this will almost always be done to determine the degree of dilation or stretch of the kidney.
- Nuclear scan of kidneys
- Voiding cystourethrogram
Treatment of Ureteropelvic Junction Obstruction
The most severe cases of ureteropelvic junction obstruction may require surgery early in life, while many do not require early surgery. The majority of cases do not require surgery at all, but do need to be checked up periodically until the obstruction has gone away.
Regular testing is required to make sure the kidney is still functioning properly. If the function of the kidney appears to be getting worse, or the obstruction is getting worse, surgery may be recommended.
Surgery to correct the blockage allows urine to flow normally, and can be performed using open methods (incision) or laparoscopic methods. Both methods are called a pyeloplasty and involve removing the abnormal part of the ureter and reconnecting it to the kidney to permit normal urine flow.
Open surgery is performed at all ages, and involves an incision in the side or back to get to the kidney and remove the blockage, then repair the ureter.
Laparoscopic surgery, a minimally invasive technique, can now be used in all ages, and usually involve the assistance of robotic surgery to help with the delicate repair. The success rates of both are similar, but children having a laparoscopic procedure can usually return home sooner (one day) and are back to normal activity sooner.
A tube called a stent may be placed to drain urine from the kidney until the patient heals. A nephrostomy tube, which is placed in the patient's side to drain urine, may also be needed for a short time after the surgery. This type of tube may also be used to treat severe infections before surgery.
Early diagnosis and treatment of ureteropelvic junction obstruction can help preserve future kidney function. Ureteropelvic junction obstruction diagnosed before birth or just after birth may actually improve on its own.
Most patients do well with no long-term consequences. Significant kidney damage may occur in those who are diagnosed later in life. Current treatment options provide good long-term outcomes. Pyeloplasty provides the greatest long-term success for severe cases of obstruction.
In severe cases, rapidly taking pressure off the kidney (kidney decompression) immediately following birth may greatly improve kidney function.
The pediatric specialists will develop a care plan that best meets the needs of each individual child.
Permanent loss of kidney function is a possible complication of untreated ureteropelvic junction obstruction. Even after treatment, the affected kidney may be at increased risk for infection or kidney stones.