Acute unilateral is a sudden blockage in one of the tubes (ureters) that drain urine from the kidneys.

See also:

• Acute bilateral obstructive uropathy
• Chronic unilateral obstructive uropathy
• Chronic bilateral obstructive uropathy
• Obstructive uropathy

Unilateral obstructive uropathy is most often caused by a kidney stone, although injury or other conditions could cause the disorder.

When urine flow is blocked, it backs up into the kidney. This leads to kidney swelling, also called hydronephrosis.

You have a greater risk for unilateral obstructive uropathy if you have ureteral stones and tumors, kidney stones, and tumors in nearby body structures such as the uterus and cervix.

Acute unilateral obstructive uropathy occurs in 1 in 1,000 people.

• Abdominal pain, right or left lower quadrant
• Abnormal urine color (tan, cola colored, tea colored)
• Back pain, may be on only one side
• Blood in the urine
• Fever
• Flank pain or pain in the side
  • Severe enough to require strong pain medicine
  • Pain on one side; it may move to the groin, genitals, and thigh
  • Pain comes and goes; intensity changes over minutes
• Foul-smelling urine
• High blood pressure that has increased recently (within 2 weeks)
• Mental status changes
• Nausea
• Urinary frequency
• Urinary urgency
• Urinary tract infection
• Vomiting

The health care provider will perform a physical exam. Pressing with the fingers on (palpation of) the belly area may reveal a swollen or tender kidney. Blood pressure may be high.

The following tests may be done:

• Basic metabolic panel
• Complete blood count (CBC)
• Urinalysis
• Urine culture

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

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

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

Antibiotics may be given if there is a urinary tract infection.

Stents or drains placed in the ureter or nearby area may provide short-term relief of symptoms. Surgery to repair the underlying cause of the obstruction will usually cure the problem.

Kidney surgery, including removal of the kidney (nephrectomy) may be needed if kidney function is poor or if there is a bad infection.

The outcome varies. The disorder may result in permanent damage to the kidney. However, kidney failure usually does not result because the second kidney continues to function.

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

Call your health care provider if you develop flank pain or other symptoms of acute unilateral obstructive.

Call your health care provider if symptoms worsen during or after 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 chance 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.

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

Peters CA. Perinatal urology. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Sauders Elsevier; 2007: chap 109.

Pais VM, Strandhoy JW, Assimos DG. Pathophysiology of urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Sauders Elsevier; 2007: chap 37.

Hsu THS, Streem SB, Nakada SY. Management of upper urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Sauders Elsevier; 2007: chap 38.

Frokiaer J, Zeidel ML. Urinary tract obstruction. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa ; Saunders Elsevier; 2007: chap 35.