Urinary Obstruction in Cats

Urinary Obstruction in Cats

A cat, facing the camera, stands with one paw in its litter boxA cat, facing the camera, stands with one paw in its litter box
A cat, facing the camera, stands with one paw in its litter boxA cat, facing the camera, stands with one paw in its litter box

Male cats frequently develop an obstruction of the urethra, which is the duct that transports urine out of the body from the bladder and through the penis. These obstructions are often a result of mucous, crystals, and even tiny bladder stones that bind together to form a plug. The opening in a male cat’s urethra is so narrow that a small amount of debris is required to cause a full obstruction and an inability to urinate. A urinary obstruction is a medical emergency and there should be no delay in seeking veterinary care.

Symptoms To Look Out For

  • Straining to urinate
  • Frequent trips in and out of the litter box
  • Excessive licking or grooming at the urogenital area
  • Passing only small volumes of urine
  • Loud meowing when attempting to urinate
  • Blood in the urine (hematuria)
  • Urinating outside of the litter box
  • No urine clumps seen in the litter box

There are multiple causes of urethral obstruction in cats, and it is often multifactorial. The most common cause, however, is an inflammation of the urethra.

Causes of Urination Problems in Cats

  • Urethritis (inflammation of the urethra)
  • Urinary tract infection
  • A stone in the urethra
  • Bladder stones
  • Masses (tumors) in the bladder or urethra
  • Stricture (narrowed area within the urogenital tract)
  • Neurologic dysfunction resulting in increased urethral tone (dyssynergia) or decreased bladder tone (atony)

Diagnostics and Tests

Physical examination and bladder palpation. Your veterinarian will feel your cat’s bladder and attempt to express urine. A urinary blockage will cause the bladder to be hard and firm like a nectarine. It is difficult for most pet owners to feel for the bladder correctly and if there is any question about whether your cat has a blockage, they should be taken to the vet for evaluation as soon as possible.

Diagnostic tests that may be needed to determine the cause of dysuria include:

  • Blood tests such as a complete blood count and serum chemistry profile may be needed to assess for changes suggesting infection or elevations in kidney values.
  • Urinalysis to identify crystals, abnormal cells, or evidence of inflammation
  • Urine culture and sensitivity to identify the presence of infection
  • Plain abdominal radiographs to assess for the presence of cystic (bladder) calculi (stones)
  • Contrast cystourethrogram. A radiographic dye study to evaluate for the presence of calculi in either the bladder or urethra. This study will also establish filling defects like mass or a tear in the urethra.
  • Abdominal ultrasound to assess the kidneys, ureters, bladder, and proximal urethra.

Initial Treatment and Hospitalization

  • Unblock. The first step for an obstructed cat is to relieve the obstruction as soon as possible. Your veterinarian will likely sedate your cat depending on how painful and awake they are, and place a urinary catheter in the urethral opening. In rare cases, your veterinarian may not be able to pass the urinary catheter successfully, and an emergency surgery known as perineal urethrostomy may be required.
  • Leave the urinary catheter in place. Once your cat’s urinary obstruction has been resolved, the catheter needs to be secured and stay in for several days. A urinary collection bag collects the urine and the volume is measured while in the hospital. The urinary catheter can be flushed if there is excessive debris causing the obstruction.
  • Intravenous fluids and medications. Once your cat’s urinary catheter has been in place, fluids and medications are critical in further stabilizing your cat.

Discharge from the Hospital

Your cat will stay in the hospital for several days before the catheter is removed. They will then be closely observed for re-blockage and will not be allowed to leave the hospital until they are able to urinate a normal volume. There can be some urinary leakage in between normal urination and this may persist for several days to weeks.

Monitoring and Treatment at Home

Once at home, your cat will need to be monitored CLOSELY over the next several weeks.

Your cat is at risk for re-blocking, especially over the first two weeks at home.

There is still inflammation and pain associated with urinating during this time and they are still at risk.

Tips for Preventing Re-blockage

  • Give all the medications prescribed for your cat. Preventing pain and inflammation is key to preventing re-obstruction.
  • Environmental enrichment. Stress relief and environmental factors play a huge role in maintaining your cat’s urinary health. Deal with any behavioral problems in the house with other cats by separating them. Give your cat stimulation with toys, food puzzles, and interactive time. Provide scratching surfaces and secure places for relaxation.
  • Dietary change. Depending on the make-up of your cat’s urine, your veterinarian will recommend a prescription diet as needed to alter the composition of your cat’s urine.
  • Increase water consumption. Provide water fountains and feed wet food to increase your cat’s water intake.
  • Feline pheromones. Synthetic feline facial pheromones (FFP) are used to help prevent a urinary obstruction. This pheromone mimics the natural marking that cats undertake when they rub their faces on objects. When FFP is applied to bedding or other surfaces in a cat’s environment, it is associated with a reduction in spraying behavior.
  • Anxiolytics. Your veterinarian may recommend a behavioral modification medication to help decrease anxiety and stress. Drugs that have been investigated include amitriptyline and fluoxetine.

Follow-up Care

Follow-up may require long-term medical management. Also, subsequent radiographs may need to be taken or repeat ultrasound examinations. Frequent examinations of the urine and repeat cultures will be required to monitor for infections and response to antibiotic management.



Lee JA, Drobatz KJ. Characterization of the clinical characteristics, electrolytes, acid-base, and renal parameters in male cats with urethral obstruction. J Vet Emerg Crit Care. 2003;13:227–233.

Finco DR, Cornelius LM. Characterization and treatment of water, electrolyte, and acid-base imbalances of induced urethral obstruction in the cat. Am J Vet Res. 1977;38:823–830.

Kruger JM, Osborne CA, Goyal SM, et al. Clinical evaluation of cats with lower urinary tract disease. J Am Vet Med Assoc. 1991;199:211–216.

Gunn‐Moore DA, Cameron ME. A pilot study using synthetic feline facial pheromone for the management of feline idiopathic cystitis. J Feline Med Surg. 2004;6(3):133‐138

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