Obstructive uropathy is a blockage that prevents urine from leaving your kidneys. When this condition develops suddenly and only affects one kidney, it’s called acute unilateral obstructive uropathy.

The blockage occurs in one of your ureters, the tubes that allow urine to pass from your kidneys to your bladder. Acute unilateral obstructive uropathy is fairly rare, affecting 1 out of every 1,000 people, according to the National Institutes of Health (NIH).

The most common cause of this condition is kidney stones. Kidney stones are small, hard mineral deposits. They form in your kidneys and can create a blockage anywhere along the urinary tract from the kidney all the way to the urethra.

This leads to a buildup of urine in the affected kidney, which in turn causes increased pressure and can damage the kidney.

Other less-common causes of this condition include:

  • injuries
  • certain cancers that affect the ureters or parts of the body that are close to the ureters (such as bladder, colon, cervix, or uterus)
  • scar tissue inside a ureter

Problems with urination

Acute unilateral obstructive uropathy may cause problems with urination. You may still pass a normal amount of urine since only one kidney is affected.

Your urine may have an unusual appearance, such as a tan or brownish color. Your urine may also contain blood or have a foul or strong odor.

Pain

Acute unilateral obstructive uropathy can cause pain in certain parts of your body, typically only if the obstruction is caused by a stone.

You may experience pain in your back or abdomen on the affected side. Pain in these areas may come in intense waves and then subside. The pain can also spread to your thigh and groin area.

Other symptoms

Other symptoms of this condition include:

  • nausea
  • vomiting
  • fever
  • elevated blood pressure

Diagnosis involves both physical examination and tests.

Physical exam

Your doctor will perform a physical exam to check for high blood pressure and tenderness in the kidney area.

Imaging tests

Imaging tests can help your doctor make a more accurate diagnosis. Your doctor will look for a blockage in your ureter or swelling in your kidney on the affected side. Tests that might be used include:

  • abdominal CT scan, which involves using several X-rays to form a detailed picture of your abdomen
  • abdominal ultrasound, which uses sound waves to create an image of your abdomen
  • intravenous pyelogram, which involves using a contrast dye and taking X-rays of your bladder and the affected kidney and ureter, examining how your kidney gets rid of the dye and how it looks once it’s in your urine

Other tests

Your doctor might perform additional tests, such as:

  • renal scan, which involves injecting a tiny amount of radioactive material into a vein in your arm that travels to your kidneys and allows your doctor to measure each individual kidney’s function
  • urinalysis, to check for signs of kidney problems and urinary tract infections
  • basic metabolic panel, which consists of blood tests that allow your doctor to check your kidney function

Treating this condition involves reducing the blockage and relieving the symptoms it causes.

Short-term relief

Your doctor might place a stent in your ureter for temporary relief. A stent is a small tube inserted into your ureter to hold it open and allow urine to pass through.

If you have a urinary tract infection, your doctor can prescribe antibiotics to clear it up.

Long-term relief

Your doctor will need to treat the underlying condition causing the blockage. This might include surgery to remove or break up kidney or bladder stones or to reduce scarring in the ureter. Medications or surgery can be used to treat an enlarged prostate.

If you have cancer, your doctor will advise you on which treatments would work best.

If you have a severe case of acute unilateral obstructive uropathy, you might need to have the affected kidney removed. This is usually done when there is a serious infection or when your kidney function is severely impaired.

Mild cases of acute unilateral obstructive uropathy are usually cured when the underlying condition is treated.

Severe cases can lead to permanent kidney damage. Since only one kidney is affected, kidney failure generally doesn’t occur. Kidney failure is a life-threatening condition that develops when both kidneys stop working.

Other complications that might develop include:

Since kidney stones cause most cases of acute unilateral obstructive uropathy, preventing these from forming can lower your risk of having a blockage:

  • You can reduce your chances of having kidney stones by drinking six to eight glasses of water each day. Your doctor might recommend more if you have a history of kidney stones.
  • Keep an eye on how much salty food you eat. Too much sodium can increase your risk of having kidney stones.
  • You may also want to watch how many oxalates you eat. Oxalates are organic acids found in beets, rhubarb, spinach, blackberries, soy products, and more. Decreasing these might help if you’re prone to developing a specific type of kidney stone called a calcium oxalate stone.