Causes

Obstructive uropathy occurs when urine cannot drain through a ureter (a tube that carries urine from the kidneys to the bladder). Urine backs up into the kidney and causes it to become swollen (hydronephrosis).

Obstructive uropathy is grouped according to whether it affects one or both kidneys and whether it occurs suddenly or is long-term:

• Chronic unilateral obstructive uropathy - Long-term uropathy that affects one kidney
• Chronic bilateral obstructive uropathy - Long-term uropathy that affects both kidneys
• Acute unilateral obstructive uropathy - Sudden uropathy that affects one kidney
• Acute bilateral obstructive uropathy - Sudden uropathy that affects both kidneys

Common causes of obstructive uropathy include the following:

• Urinary tract stones
  • Ureteral stones
  • Bladder stones
• Urinary tract tumors
• Retroperitoneal fibrosis
• Benign prostatic hyperplasia (enlarged prostate)
• Tumors of nearby organs
• Bladder or ureteral cancer
• Colon cancer
• Cervical cancer
• Uterine cancer
• Any cancer that spreads
• Idiopathic hydronephrosis of pregnancy

Symptoms

Symptoms associated with obstructive uropathy vary depending on whether the obstruction is acute or chronic, whether it is unilateral or bilateral, whether it is complete or partial, and what caused it. Common symptoms of obstructive uropathy include the following:

• Flank pain
  • Bilateral or unilateral
  • Colicky or severe
• Urinary tract infection
• Fever
• Difficulty or pain while urinating
• Nausea or vomiting
• Renal failure
• Weight gain or swelling (edema)
• Decreased urine output
• Blood in the urine

Exams and Tests

The diagnosis of obstructive uropathy is made on imaging studies. Common radiographic studies used to diagnose obstructive uropathy include:

• Abdominal ultrasound
• Abdominal CT scan
• Intravenous pyelogram (IVP)
• Voiding cystourethrogram
• Renal nuclear scan

Treatment

Stents or drains placed in the ureter or in the renal pelvis may provide short-term relief of symptoms. Nephrostomy tubes, which drain urine from the kidneys through the back, may be used to bypass the obstruction. A Foley catheter, inserted through the urethra, may also be helpful.

Although temporary relief from the obstruction can be achieved without surgery, the cause of the obstruction must be removed and the urinary system repaired. Long-term relief from obstructive uropathy requires surgery.

Outlook (Prognosis)

If an acute obstruction is rapidly diagnosed and repaired, kidney damage is minimal or reversible -- regardless of being unilateral or bilateral.

If chronic unilateral obstruction is not relieved promptly, there could be permanent damage to the kidney. Chronic unilateral obstruction usually does not cause kidney insufficiency or failure because most patients have normal function from the other kidney.

Chronic bilateral obstruction may lead to kidney insufficiency or failure because both kidneys may become damaged and fail to function even after the obstruction is repaired.

For more specific information, see the individual articles below:

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

Possible Complications

Obstructive uropathy can cause permanent and severe damage to the kidneys, resulting in renal failure. Obstructive uropathy caused by bladder outlet obstruction can lead to permanent and severe damage to the bladder, resulting in problems such as incontinence and urinary retention.

When to Contact a Medical Professional

Contact your health care provider if you have symptoms of obstructive uropathy or believe that you may be suffering from this condition.

Prevention

Obstructive uropathy can be prevented by addressing any underlying disorders that can cause it.

Alternative Names

Uropathy - obstructive

References

Pais VM Jr, Strandhoy JW, Assimos DG. Pathophysiology of urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Saunders 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: Saunders Elsevier; 2007:chap 38.

McAninch JW, Santucci RA. Renal and ureteral trauma. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 39.

Frøkiaer 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.

Update Date: 3/22/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.