Ureteral Obstruction

What Is Acute Unilateral Obstructive Uropathy?

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, which are the tubes that allow urine to pass from your kidneys to your bladder. This condition is fairly rare, affecting one out of every 1,000 people, according to the National Institutes of Health (NIH).

What Causes Acute Unilateral Obstructive Uropathy?

The most common cause of this condition is kidney stones. These stones, which are made of tiny crystals, can form in one of your kidneys and create a blockage. This leads to a buildup of urine in the affected kidney, which in turn causes swelling.

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, cervical, or uterine cancer
  • scar tissue inside a ureter
  • enlarged prostate
  • bladder stones

What Are the Symptoms of Acute Unilateral Obstructive Uropathy?

Problems With Urination

Acute unilateral obstructive uropathy will usually cause problems with urination. You should still be able to pass a normal amount of urine since only one kidney is affected, but you might have to urinate more often than usual. Your urine might have an unusual appearance, such as a tan or brownish color. Your urine may contain blood or have a foul or strong odor.


Acute unilateral obstructive uropathy can cause pain in certain parts of your body. This pain might occur in your back or abdomen on the affected side. It can also occur in the area between your back and upper abdomen on the affected side. When pain occurs in this region, you might experience episodes when it becomes more intense and then subsides. The pain might also spread to your thigh and groin area.

Other Symptoms

Other symptoms of this condition include:

  • nausea
  • vomiting
  • fever
  • a recent increase in blood pressure

How Is Acute Unilateral Obstructive Uropathy Diagnosed?

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 will 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
  • intravenous pyelogram, which involves using a contrast dye and taking X-rays of your bladder and the affected kidney and ureter. Your doctor will examine how your kidney gets rid of the dye and how it looks once it’s in your urine.
  • abdominal ultrasound, which uses sound waves to create an image of your abdomen

Other Tests

Your doctor might perform additional tests, such as:

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

Treatment Options

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.

Long Term Outlook

Mild cases of acute unilateral obstructive uropathy are usually successfully 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

  • chronic unilateral obstructive uropathy, which is a long-term blockage in the ureter
  • frequent or chronic urinary tract infections
  • high blood pressure (hypertension)

How Can I Prevent Acute Unilateral Obstructive Uropathy?

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 that you drink more if you have a history of kidney stones.

Avoid eating foods that are high in sodium, since a high salt intake can increase the risk of having kidney stones. You might also benefit from eating fewer foods that are high in oxalates, an organic acid found in beets, rhubarb, spinach, blackberries, and soy products. This might help if you’re prone to developing a specific type of kidney stone called a calcium oxalate stone.