Urine is drained from the kidneys through tubes called ureters. Obstructive uropathy occurs when a one or both ureters becomes blocked; the condition may be acute or chronic.

Chronic unilateral obstructive uropathy involves a slow, progressive blockage of one ureter, resulting in a backup of urine and injury to the kidney.

Unilateral obstructive uropathy occurs when urine cannot drain through a ureter because of an obstruction, often ureteral or kidney stones. Urine backs up into the kidney and causes distention of the renal pelvis and calyces (hydronephrosis).

Risks for unilateral obstructive uropathy include ureteral stones and tumors, kidney stones, and tumors in surrounding structures such as the uterine cervix.

The disorder damages structures of the urinary tract. It may result in permanent damage to the kidney and may be a cause of hypertension. It usually does not cause kidney failure because the second kidney continues to function.

Chronic unilateral obstructive uropathy occurs in approximately 5 out of every 1,000 people.

• Flank pain
  • Severe
  • May travel or radiate to the groin, genitals, thigh
  • Colicky or spasmodic
  • On one side
• Back pain, may be on only one side
• Abdominal pain, right or left lower quadrant
• Blood in the urine
• Urinary tract infection
• Painful urination
• Increased urinary frequency/urgency
• A need to urinate at night

An examination of the abdomen reveals an enlarged kidney. Blood pressure may be elevated. A urinalysis may reveal blood in the urine. A urine culture may reveal an infection.

Hydronephrosis or obstruction of the ureter may appear on these tests:

• Intravenous pyelogram (IVP)
• Abdominal ultrasound
• Kidney or abdominal CT scan

Treatment focuses on eliminating or minimizing the obstruction.

Stents or drains placed in the ureter or in the renal pelvis may provide short-term relief of symptoms. A nephrostomy tube, which drains urine from the kidney through the back, may be used to alleviate the obstruction. Surgery to repair the underlying cause of the obstruction will usually eliminate the problem.

The outcome varies. Kidney damage may be permanent. However, if the cause of the obstruction is diagnosed and treated early, the damage may be temporary. If only one kidney is involved, the other kidney usually continues to function adequately and renal insufficiency or renal failure does not occur.

• Permanent failure of the affected kidney (chronic renal failure)
• Chronic or recurrent urinary tract infection
• Hypertension

Call your health care provider if flank pain or other symptoms of chronic unilateral obstructive uropathy develops.

Call your health care provider if symptoms worsen or persist despite treatment, or new symptoms develop.

If you are prone to kidney stones, drink plenty of water (6 to 8 glasses per day) to reduce the chances of their formation.

Research suggests that a diet low in sodium and oxalate and high in citrate significantly reduces risk of calcium-based kidney stone formation. Consult with a nutritionist for more information on such diets.

Urinary tract infections should be treated promptly and thoroughly.

Seek medical attention if kidney stones persist or recur to identify the cause and to prevent new stones from forming.