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 one of the tubes that carries urine from the kidney to the bladder. Urine backs up and causes kidney swelling (hydronephrosis).

This condition is usually caused by a blockage from ureteral or kidney stones.

Risks for unilateral obstructive uropathy include ureteral stones and tumors, kidney stones, and tumors in surrounding structures such as uterus, cervix, or lymph nodes.

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 may reveal 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