Chronic bilateral obstructive uropathy

Definition

Chronic bilateral obstructive uropathy is the prolonged or progressive blockage of urine flow from both kidneys.

Alternative Names

Causes

Obstructive uropathy occurs when the flow of urine from the kidneys is blocked (obstructed). This causes kidney swelling and damage. The blockage can occur anywhere along the urinary tract.

A slow blockage that gets worse over time causes chronic bilateral obstructive uropathy. Bilateral means the blockage affects both kidneys. The most common cause of this is bladder outlet blockage. In this condition, the kidneys produce urine in the normal manner but the urine cannot leave the bladder. Urine may back up behind this blockage and cause damage to the structures of the urinary tract.

When the blockage causes urine to back up into both kidneys, hydronephrosis (swelling of the kidneys) results. If both kidneys are affected, hypertension and renal failure may occur.

In men, the most common cause of chronic bilateral obstructive uropathy is due to the blockage of  of both ureters (the tubes between the kidneys and the bladder), the bladder, or the urethra. In men, this is most often as a result of a benign enlargement of the prostate (BPH). Such blockage is much less common in women.

Other causes of chronic bilateral obstructive uropathy include:

• Bladder tumors
• Prostate tumors
• Tumors or masses of the uterus or other structures around the bladder neck or urethra
• Retroperitoneal fibrosis  
• Narrowing of the urethra due to a birth defect or scar tissue

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

See also: acute bilateral obstructive uropathy

Symptoms

Symptoms depend on the time course of the obstruction and where in the urinary tract the obstruction occurs.

Some of the most common symptoms of chronic obstructive uropathy include:

• 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 times of increased urine output and decreased urine output
• Fever and chills (if there is also urinary infection)

• Nail problems
• High blood pressure
• Abnormal urine color

Exams and Tests

A physical exam may show swollen or tender kidneys. The bladder may be large and full. A rectal examination may reveal an enlarged prostate. Signs and symptoms of chronic renal failure may be present. Blood pressure may be high.

• A urinalysis and a urine culture (clean catch) may show a urinary tract infection.
• A CBC may show an increased white blood cell count  
• A basic metabolic panel will reveal patient's current kidney function as well as electrolyte balance, which may be abnormal.
• A bladder scan (ultrasound) may show a large amount of urine in the bladder after urinating (more than 50 mL).
• Uroflowmetry may reveal decreased urinary flow due to a swollen prostate (BPH).

The following tests may show hydronephrosis (swelling of kidneys):

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

Treatment

The goal of treatment is to get rid of the blockage. 

If the blockage is at the bladder neck, a tube (catheter) inserted into the bladder area may provide short-term relief.

Surgery such as TURP (transurethral resection of the prostate) or newer techniques that use laser or heat therapy to shrink the prostate may be helpful if the cause of the problem is benign prostatic hyperplasia.

Other types of surgery may be needed for other disorders causing blockage of the urethra or bladder neck.

If the blockage occurs in the tubes (ureters) that move urine from the kidney to the bladder, a stent or nephrostomy tube may temporarily solve the problem. Surgery may be required to cure this type of blockage.

Antibiotics may be needed to treat urinary tract infection. If there is kidney failure, dialysis may be necessary.

Outlook (Prognosis)

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

Possible Complications

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

When to Contact a Medical Professional

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

Prevention

Routine screening (and treatment) for lower urinary tract disorders may help prevent this condition. A digital rectal exam is used to screen men for prostate problems.

Walsh PC. Campbell's Urology. 8th ed. St. Louis, Mo: WB Saunders; 2002:412. 

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