Unilateral obstructive uropathy usually occurs when ureteral or kidney stones block the flow of urine. Urine backs up and causes kidney swelling (hydronephrosis ).

Risk factors for unilateral obstructive uropathy include:

• Kidney stones
• Tumors in surrounding structures such as uterus, cervix, or lymph nodes
• Ureteral stones and tumors

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

• Abdominal pain , right or left lower belly area
• Back pain , may be on only one side
• Blood in the urine
• Increased urinary frequency/urgency
• Frequent need to urinate at night
• Painful urination
• Severe flank pain that may occur on one side, but may also be felt in the groin, thigh, and genitals
• Urinary tract infection

Your health care provider will perform a physical exam, which includes feeling your abdomen. The exam may reveal a swollen kidney.

A blood pressure measure may reveal high blood pressure. A urinalysis may show blood in the urine . A urine culture can determine if you have an infection.

Kidney swelling or blockage of the ureter may appear on these tests:

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

The goal of treatment is to reduce or remove the blockage.

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 relieve the blockage.

Surgery to repair the underlying cause will usually correct the blockage.

This condition damages the structures of the urinary tract. It may result in permanent damage to the kidney. If only one kidney is involved, the other kidney usually continues to work, and kidney failure or insufficiency does not occur.

• Chronic or recurrent urinary tract infection
• High blood pressure
• Permanent failure of the affected kidney (chronic kidney failure )

Call your doctor if you have flank pain or other symptoms of chronic unilateral obstructive uropathy.

If you have already been diagnosed with this condition, call your health care provider if symptoms worsen or persist despite treatment, or if 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.

A diet low in sodium and oxalates and high in citrate may reduce your risk of calcium-based kidney stone formation. Talk to a nutritionist for more information on such diets.

Urinary tract infections should be treated promptly and thoroughly.

Wein AJ, et al. Campbell-Walsh Urology. 9th ed. St. Louis, Mo: WB Saunders; 2007.

Goldman L, Ausiello D, et al. Cecil Textbook of Medicine, 22nd ed. Philadelphia, Pa: WB Saunders; 2004:741-742.