Ureteropelvic Junction Obstruction (UPJO)
What is it?
An ureteropelvic junction obstruction
(UPJO) is a blockage where the ureter and
renal pelvis meet. The ureter is a tube that
drains urine from the kidney to the
bladder. The renal pelvis is the collecting
area of the kidney. A blockage at this
place can lead to urine backing up,
causing the kidney to enlarge
How common is it?
UPJO is one of the most common birth
defects of the ureter. It is more common
in males. It affects the left kidney more
than the right. A blockage in both kidneys
occurs in about 10-15% of the cases.
What causes it?
This defect occurs while the kidney develops in the
unborn infant. The cause of UPJO is not well known.
The result is a narrow segment of the ureter that causes
a blockage. It can often be found on prenatal
What are the signs and symptoms?
UPJO may cause flank or back pain, blood in the urine, and repeat urinary tract infections. But
most often there are no symptoms.
How is it diagnosed?
Special tests are done to look for UPJO. A renal ultrasound can help find out if the kidney is
enlarged. A renal scan is needed to confirm blockage and assess how well the kidney is
working. It is done by putting a dye into a vein and taking pictures as it travels into the kidney
and down the ureter to the bladder.
How is it treated?
If the UPJO is severe, an operation called a pyeloplasty is done. The blockage is removed and
the ureter is re-attached to the kidney. This is done in the operating room under general
anesthesia. In some cases, a stent may be placed in the ureter to help drain the kidney. The stent
will remain in place for about six weeks. Risks linked with a pyeloplasty include return of the
blockage and infection. The success rate is greater than 95%.
How do I get more information?
UW Health Urology 608-263-4757
UW Health at The American Center Urology 608-440-6464
UW Health One South Park Urology 608-287-2900
After Hours, Nights, Weekends, and Holidays, the clinic number is answered by the paging
operator. Ask for the Urology Doctor on call. Leave your name and phone number with the area
code. The doctor will call you back.
Toll Free: 1-844-607-4800
Your urology doctor is _________________
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