Obstructive uropathy occurs when the flow of urine from the kidneys is blocked. This causes the kidneys to dilate and become damaged. Obstruction can occur anywhere in the the urinary system. If the obstruction is bilateral (affecting both kidneys), bladder outlet obstruction is the most common cause. The kidneys produce urine in the normal manner but the urine cannot leave the bladder because it is blocked. Urine may back up behind this obstruction and cause damage to the structures of the urinary tract.

When the obstruction causes urine to back up into both kidneys, hydronephrosis (swelling of the kidneys) results. If both kidneys are affected, this can eventually lead to hypertension and/or renal failure. Sudden blockage causes acute bilateral obstructive uropathy, while slow, progressive blockage causes chronic bilateral obstructive uropathy.

Chronic bilateral obstructive uropathy is caused by gradual blockage of both ureters (the tubes between the kidneys and the bladder), the bladder, or the urethra, resulting in a backup of urine into both kidneys. In men, this is most often as a result of a benign enlargement of the prostate (BPH). Bladder outlet obstruction is much less common in women but can be caused by a bladder cystocele.

Other causes include bladder tumors, prostate tumors, and tumors or masses of the uterus or other structures around the bladder neck or urethra, including retroperitoneal fibrosis. Narrowing of the urethra may also cause obstruction secondary to a congenital (present from birth) deformity or scar tissue from injury or infection.

Initially, the bladder reacts to the obstruction by increased irritability. There is a stronger and more frequent urge to urinate, and bladder spasms or incontinence may occur. As urine accumulates and the bladder fails to empty completely (urine stasis), urinary tract infections may occur. Symptoms are the result of urinary retention and damage to the bladder, ureters, and kidneys.

Chronic bilateral obstructive uropathy occurs in about 1 out of every 1,000 people.

• Stronger and more frequent urge to urinate
• Difficulty initiating the flow of urine (urinary hesitancy)
• Dribbling of urine, incontinence
• Decreased urine output
• Decrease in the force of the urinary stream
• Increased need to urinate at night
• Burning or stinging with urination
• Feeling of incomplete emptying of the bladder
• Alternating episodes of increased urine output and decreased urine output
• Fever and chills (if there is also urinary infection)

• Nail abnormalities
• High blood pressure
• Abnormal urine color

• A urinalysis and a urine culture (clean catch) may show a urinary tract infection.
• A CBC may show leukocytosis (increased white blood cell count) if there is an infection.
• A basic metabolic panel will reveal patient's current kidney function as well as electrolyte balance, which may be abnormal.
• A bladder scan (ultrasound) shows significant post-void residual (more than 50 mL of urine remains in the bladder after urinating).
• Uroflowmetry may reveal decreased urinary flow from prostatic blockage (BPH).

• Abdominal ultrasound
• CT scan of abdomen and pelvis
• Renal scan

The initial treatment focuses on relieving urinary obstruction.

If the obstruction is at the bladder neck, catheterization may provide short-term relief. An implanted urinary (Foley) catheter, intermittent self catheterizations, or a suprapubic tube (tube directly draining the bladder through the abdominal wall) may be used, depending on the particular case.

Surgery of the prostate, such as by a TURP (transurethral resection of the prostate) provides correction of enlarged prostate. Other surgical intervention may be appropriate for other disorders causing obstruction of the urethra or bladder neck.

If the obstruction is at the level of the ureters, ureteral stents or nephrostomy tubes may temporarily solve the problem. Surgery is usually required for permanent resolution of the obstruction depending on the cause of the obstruction.

Antibiotics may be needed to treat urinary tract infection. Treatment for chronic renal failure such as correction of electrolyte abnormalities and dialysis may be necessary.

If the obstruction is corrected before the development of renal failure, bilateral obstructive uropathy may be reversible.

If chronic renal failure develops, long-term kidney damage is likely. This can be life-threatening.

Patients with chronic obstruction are at a higher risk for post-obstructive diuresis, which occurs after obstruction is relieved (such as with a Foley catheter) and the kidneys have not had chance to adapt to the change and are unable to concentrate the urine. Thus, the patient voids large quantities of urine that hasn't been properly processed. This can also be a life-threatening condition and close monitoring is required.

If the obstruction was caused by a cancer, the ultimate outcome is determined by the extent of disease and its response to therapy.

• Chronic renal failure
• Post-obstructive diuresis
• Chronic or recurrent urinary tract infection
• Chronic voiding dysfunction (incontinence/urinary retention)
• Urolithiasis (stone formation)

Call your health care provider if decreased urine output or other symptoms of chronic bilateral obstructive uropathy develop.

This condition may be prevented or prevented from causing serious damage by routine screening by primary care physician for signs and symptoms of lower urinary tract disorders, including a rectal examination in men.