Ureteropelvic Junction Obstruction

What is ureteropelvic junction (UPJ) obstruction?

Ureteropelvic junction (UPJ) obstruction is a blockage in the renal pelvis of your kidney. Each of your kidneys has a renal pelvis. The renal pelvis is located at the upper end of each tube that drains pee from your kidneys to your bladder (ureter). The renal pelvis has a funnel-like shape, and it collects pee.

Typically, each kidney has one ureter. Your kidneys filter fluids and waste out of your blood and create pee. Pee collects in your renal pelvis, flows through the UPJ and then flows from your ureters to your bladder.

If you have a UPJ obstruction, your pee flow is slow or stops completely. This increases your risk of kidney damage.

In most cases, a UPJ obstruction is present at birth (congenital urinary abnormality). It also typically affects only one kidney.

Other names for ureteropelvic junction obstruction include:

• UP junction obstruction
• Obstruction of the ureteropelvic junction
• UPJO

Is UPJ obstruction serious?

Yes, a UPJ obstruction is serious. Without treatment, a UPJ obstruction can cause kidney failure.

How common is ureteropelvic junction obstruction?

UPJ obstruction occurs in about 1 of every 1,500 births.

What are the symptoms of ureteropelvic junction obstruction?

Common symptoms of ureteropelvic junction obstruction include:

• A lump in your abdomen
• Urinary tract infection (UTI) with fever
• Flank pain
• Kidney stones
• Blood in your pee (hematuria)
• Nausea and vomiting
• Developmental delay

What is the most common cause of ureteropelvic junction obstruction?

Most ureteropelvic junction obstructions are present at birth. That means the structures of the ureter or kidney didn’t form as expected during fetal development. The other reason is that there’s a blood vessel going across the UPJ and causing compression. They typically occur randomly. But sometimes, you may be more likely to have a UPJ obstruction if someone else in your family has one.

UPJ obstruction is rare in adults. But it can happen after:

• Kidney stones
• Upper UTIs
• Surgery in the area
• Swelling in the upper part of your urinary system

Who does this condition affect?

People assigned male at birth (AMAB) are more than twice as likely to have UPJ obstruction as people assigned female at birth (AFAB). Your left kidney is also about twice as likely to have a UPJ obstruction than your right kidney.

What are the complications of ureteropelvic junction obstruction?

Ureteropelvic junction obstruction complications may include:

• UTIs that go away and come back, with swelling of the fat around your kidneys (perinephric stranding)
• Long-lasting (chronic) pain in your affected area
• The development of more kidney stones (secondary kidney stones)

Without treatment, a prolonged UPJ obstruction can cause kidney damage or kidney failure.

How is ureteropelvic junction obstruction diagnosed?

In most cases, healthcare providers can diagnose ureteropelvic junction obstruction during prenatal imaging (ultrasound). As pee backs up due to the blockage, the kidney will swell beyond its typical size (hydronephrosis).

After birth, providers can order tests that measure how well your kidneys are making and draining pee. These tests may include:

• Blood tests and pee tests (urinalysis). Blood urea nitrogen (BUN) and creatinine clearance tests can see how well your kidneys filter blood.
• Intravenous pyelogram (IVP). A provider will inject a dye into one of your veins (usually in an arm) and see how it moves (trace it) with an X-ray as it flows through your kidney, renal pelvis and ureter.
• Renal scan. A provider will inject a radioactive substance into one of your veins and trace it with a special camera. It shows how well your kidneys work and the size of the blockage.
• Ultrasound, CT scan and MRI. These imaging tests can show obstructions in your kidney as well as the structure of your kidneys, ureters and bladder.

How do you fix a UPJ obstruction?

It depends. If your infant has a ureteropelvic junction obstruction, it may improve on its own within the first 18 months of life. During this time, your child’s healthcare provider will schedule regular ultrasounds and scans to make sure the UPJ obstruction isn’t causing any harm.

If your child’s pee flow doesn’t improve and the obstruction is still there after your child is 18 months old, they’ll likely need an open pyeloplasty. During this surgical procedure, a pediatric urologist will use a surgical knife (scalpel) to make one large cut (incision), remove the obstruction and reattach your child’s ureter to their kidney with a wider opening. An open pyeloplasty usually takes a few hours to complete and has about a 95% success rate.

In some cases, the surgeon may be able to perform a minimally invasive pyeloplasty with a surgical robot to treat UPJ obstruction. They’ll make one small incision and use a surgical robot to operate a laparoscope and other surgical tools. A minimally invasive pyeloplasty has a comparable success rate to an open pyeloplasty. But it’s more technically demanding of a surgeon. It also depends on a child’s age and size.

Another option is an endopyelotomy. The surgeon will insert an endoscope through your urethra, past your ureter, to see the obstruction. They’ll then insert a wire through a channel in the endoscope and use it to cut the obstruction and insert a drain. The drain will remain for a few weeks while you heal. An endopyelotomy doesn’t require any incisions and is more comfortable than an open or robotic-assisted laparoscopic pyeloplasty. But it has a lower success rate. You may need an endopyelotomy more than once.

How soon after treatment will I feel better?

It depends on the type of procedure you have to treat ureteropelvic junction obstruction. Most people recover in two to four weeks. But your body is unique, and how you recover from UPJ treatment may be different from others. A healthcare provider will give you a better idea of what to expect.

Can ureteropelvic junction obstruction be prevented?

Medical researchers haven’t found a link between diet and nutrition during pregnancy and the formation of UPJ obstruction in a developing fetus. You can’t prevent UPJ obstructions that are present at birth.

In adults without a congenital history of UPJ obstruction, you can help reduce your chances by avoiding:

• Kidney stones
• UTIs
• Trauma to your kidneys

What is the prognosis for ureteropelvic junction obstruction?

With early diagnosis and treatment, the outlook for ureteropelvic junction obstruction is good. Most children don’t have long-term complications. And if a healthcare provider diagnoses it before birth, it may go away without treatment.

If a provider diagnoses you with UPJ obstruction later in life, you may be more likely to have kidney damage. In severe cases, untreated UPJ obstruction can cause kidney failure and death.

When should I see a healthcare provider?

Reach out to a healthcare provider if you or your infant has the following symptoms:

• Bloody pee
• An abdominal lump
• Upper abdominal or back pain
• Fever
• Growth faltering (failure to thrive)

When should I go to the ER?

Go to the nearest emergency room if you can’t pee.

What questions should I ask a healthcare provider?

You may want to ask your provider:

• How will you diagnose ureteropelvic junction obstruction?
• Do you think my child’s UPJ obstruction will go away without treatment?
• What are the treatment options?
• If surgery is necessary, what approach do you recommend?
• What are the chances UPJ obstruction comes back?

What is the difference between a ureteropelvic junction obstruction and a ureterovesical junction (UVJ) obstruction?

Ureteropelvic junction obstructions and ureterovesical junction (UVJ) obstructions happen at opposite ends of your ureter. The UVJ is where your ureter connects to your bladder. A UVJ obstruction occurs in this area. A ureteropelvic junction obstruction occurs in the renal pelvis, where your ureter connects to your kidney.