Acute urethral obstruction

Alternative names
Urethral obstruction; Acute bilateral obstructive uropathy; Obstructive uropathy - bilateral - acute

Acute bilateral obstructive uropathy is a sudden blockage of the flow of urine from both kidneys, which can cause the backup of urine and injure the kidneys.

Causes, incidence, and risk factors

Obstructive uropathy occurs when the flow of urine is blocked. The kidneys continue to produce urine in the normal manner, but the urine does not drain properly because of the obstruction. Pressure in the urinary tract rises, resulting in hydronephrosis (swelling of the kidneys) and bilateral obstructive uropathy (damage to both kidneys caused by obstruction of urine). Obstructive uropathy may eventually lead to hypertension or acute renal failure. Sudden blockage causes acute bilateral obstructive uropathy, while slow, progressive blockage causes chronic bilateral obstructive uropathy.

Acute bilateral obstructive uropathy is usually caused by a blockage of the urethra that occurs (suddenly or over a brief time). In men, it is most often a result of an enlarged prostate. Other causes in men include Prostate cancer, bilateral obstructing kidney stones and bladder cancer. It is much less common in women, but may occur as a result of a bladder cystocele, pregnancy, injury from surgery involving the reproductive organs, or Cervical cancer. Other causes include posterior urethral valves in infant boys, neurogenic bladder, papillary necrosis, coagulated blood, fungus and other rare retroperitoneal processes.

At first, the bladder reacts to the obstruction with increased irritability. There is a stronger and more frequent urge to urinate, and bladder spasms or incontinence may occur. As urine accumulates, it may lead to stasis of urine and Urinary tract infections (see UTI - acute). Urine may back up into the ureters (tubes which carry urine from the kidneys to the bladder) and kidney.

Acute bilateral obstructive uropathy occurs in about 5 out of 10,000 people.


  • Decreased urine output (may be less than 10 mL per day)  
  • Urinary hesitancy  
  • Abnormal urine flow - dribbling at the end of urination  
  • Incontinence  
  • Decrease in the force of the urinary stream, stream small and weak  
  • Increased urinary frequency or urgency  
  • Need to urinate at night  
  • Frequent strong urge to urinate  
  • Burning or stinging with urination  
  • Feeling of incomplete emptying of the bladder  
  • Sudden flank pain or pain on both sides  
  • Blood in the urine  
  • Fever  
  • nausea and vomiting  
  • high blood pressure (hypertension), recent increase  
  • Urine, abnormal color

Signs and tests
Examination by touch (palpation) shows enlarged and tender kidneys. Palpation over the bladder shows bladder distention. Placement of a catheter in the bladder may relieve the lack of urine output. Post-void residuals (catheterized measurement of the volume of urine that remains in the bladder after urinating) are repeatedly more than 50 mL. Rectal examination usually shows an enlarged prostate in men. Blood pressure may be elevated. There may be signs and symptoms of acute renal failure. Fever with infection is common.

  • A urinalysis may be abnormal.  
  • A clean catch urine specimen may show infection within the urinary tract.  
  • Serum creatinine may increase suddenly, by 2 mg/dL or more over a two-week period.  
  • Creatinine clearance may be decreased.  
  • Blood BUN may increase suddenly.  
  • A blood potassium test may be elevated.  
  • Arterial blood gas and blood chemistries may show metabolic acidosis.

Hydronephrosis may be apparent in any of the following tests:

This disease may also alter the results of the following tests:

  • Radionuclide cystogram  
  • Creatinine - urine


Treatment is focused on relieving the obstruction, which will allow urine to drain from the urinary tract. This allows the body to begin the natural healing process.

Catheterization may provide short-term relief of symptoms. This may be a urethral (Foley) catheter, intermittent self-catheterization, or a suprapubic tube (tube directly draining the bladder through the abdominal wall).

Antibiotics or other medications may need to be given upon diagnosis of infection or renal failure. Initial evaluation and treatment may require hospitalization.

Long-term relief is accomplished through correction of the cause of the obstruction.

Surgical reduction of the prostate - such as by a TURP (transurethral resection of the prostate) - may relieve blockage from enlarged prostate. Surgical intervention may also be appropriate for other disorders causing blockage of the urethra or bladder neck.

Expectations (prognosis)

If the acute obstruction is quickly relieved, symptoms usually subside within hours to days . If untreated, the disorder causes progressive damage to the kidneys, and may cause kidney failure and death.


Calling your health care provider

Call your health care provider if decreased urine output, difficulty urinating, flank pain, or other symptoms of acute bilateral obstructive uropathy occur.


This disorder may not be preventable in many cases. Routine annual physicals with a primary care physician are recommended. If found to have acute obstructive uropathy, the patient should go to the nearest emergency room and consult a urologist.

Johns Hopkins patient information

Last revised: December 4, 2012
by Janet G. Derge, M.D.

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