Feline Urinary Obstruction

Feline Urinary Obstruction

Animals Affected

Male cats


Feline urinary obstruction is a life-threatening medical emergency.  It occurs when a plug of mucus or a small stone lodges in the urethra and obstructs it.  Strong spasms of the urethra may contribute to the syndrome.  Because the urethra is the structure used to drain urine from the bladder, this situation makes urination very difficult or impossible.

Cats with urinary obstruction are unable to void their bladders normally. Because of this, urine builds up in the bladder until its maximum capacity is reached. At that point, the kidneys stop producing urine. Untreated, this rapidly leads to kidney failure, electrolyte imbalances, and death.


Initial symptoms may look similar to those of FLUTD (feline lower urinary tract disease) and bladder infections. They are related to discomfort from the inability to urinate, and may include:

  • Straining to urinate
  • Frequent attempts to urinate without producing urine
  • Vocalizing or howling in pain when attempting to urinate
  • Licking the penis
  • Hiding or becoming aggressive
  • Exhibiting pain when the abdomen is handled

As the syndrome progresses and the kidneys stop producing urine, the cat will become sick and may show symptoms such as:

Risk Factors

  • Untreated FLUTD is a major risk factor. However, any cat who has been diagnosed with FLUTD is at increased risk, even if the FLUTD is being treated. For some cats, urinary obstruction will be the first symptom of FLUTD.
  • Younger cats suffer higher rates of urinary obstruction than elderly cats.
  • Cats that have previously suffered urinary obstruction are at high risk of recurrence.
  • A hereditary (genetic) component may contribute to the syndrome.


  • Untreated urinary obstruction is almost always fatal.
  • After successful treatment, recurrence of urinary obstruction is common.
  • Even with appropriate treatment, successful resolution of the syndrome cannot be guaranteed. A small percentage of cats with urinary obstruction die despite appropriate treatment.


Diagnosis is based on physical examination, including palpation of the bladder by an experienced practitioner.  X-rays or ultrasound of the bladder may be used as an aid in diagnosis.


Treatment involves emergency hospitalization and catheterization of the bladder to allow urine to drain. Most cats require several days of hospitalization with intravenous fluids, continuous monitoring of urine output, antibiotics, and pain killers or anti-inflammatory medications. Treatment is not guaranteed to be successful.

A surgical procedure called perineal urethrostomy can be performed to prevent relapses. This surgery usually is reserved for cats who have suffered multiple episodes of urinary obstruction.


After successful treatment for urinary obstruction, it is critical to treat the cat for underlying FLUTD to prevent relapses. Please see the article entitled FUS/FLUTD for more information.

Cats recovering from urinary obstruction may benefit from medications such as phenoxybenzamine, prazosin, or diazepam to relax the muscles of the urethra and promote normal urine flow.



Due to the extremely serious nature of this syndrome, any male cat who shows symptoms consistent with urinary obstruction should receive emergency veterinary attention.

The importance of follow-up care and treatment of underlying FLUTD to prevent relapses cannot be overstated.

Urinary obstruction is essentially unheard of in female cats.

Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.