Veterinarian-written / veterinarian-approved articles for your cat.

Urinary System Blockage

If you suspect that your cat may have a urinary system blockage, meaning he cannot urinate, it is an emergency situation.

cat_litterIf the blockage lasts for greater than a day, death can result from the buildup of toxins.

Kidney failure or burst bladder may occur as other complications.

If you have not been checking the box daily, if your cat goes outdoors, or you have a multi-cat household, it may be tough to tell exactly when he last urinated, but do your best! See the signs below, and if in doubt, it is essential that you seek veterinary attention for your cat immediately!

Look for:

  • No urine produced
  • Straining in the box
  • Blood or crystals in the fur at the back end where the urine comes out
  • Lethargy, hiding, inactivity, aggression, restlessness, crying, pacing
  • Vomiting
  • Swollen hard tummy
  • Loss of appetite
  • Small amounts of urine +/- blood in the box or elsewhere in the home.

Complete blockage of the flow of urine out of the urethra (the tube from bladder to outside) is a very serious condition. This problem is a consequence of some of the conditions associated with Feline Lower Urinary Tract Disease (FLUTD). There are many causes of urethra blockage, but the two most common are stones and plugs. Mucous, crystals, and tiny bits of urinary debris (cells and protein) can aggregate together to form a soft, compressible material that can lodge in the urethra and completely block the flow of urine. This is what plugs are. Stones, as the name implies, are mineral “stones” that are hard, and may or may not be round in shape.

Blockage is most common in male cats due to the fact that their urethra is longer and narrower than in the females. Female cats can become blocked though! Cats that are straining to urinate frequently and not producing urine may be blocked or just exhibiting these signs due to bladder discomfort associated with sterile interstitial cystitis, or bladder infection; other types of conditions we class as FLUTD complex.

With simple palpation of the abdomen, the veterinarian can usually quickly determine whether blockage is the problem.

Although on occasion, gentle pressure by the veterinarian on the bladder can expel the obstruction and relieve the blockage, usually a urinary catheter will be required. The passage of the catheter into the bladder requires sedation or light anesthesia unless the patient is near death. Although most catheters can be inserted, occasionally the stone or plug is so tightly lodged within the urethra that the urinary catheter cannot be passed. Flushing may be done to help move it out back into the bladder.

If male cats develop repeated episodes of this condition, a surgery called “ perineal urethrostomy” will be performed to permanently change the size of the outflow tract to make it less likely a stone can become stuck. In this surgery, the urethra is shortened and widened making him more like a girl cat in the anatomy. The male cat will then urinate from an opening in the skin below the anus, and not out of the penis.

The surgery will not prevent subsequent bouts of blockage, and may slightly predispose the cat to bladder infections. This is life saving surgery though, since repeated bouts or intractable blockage will lead to death of the cat.

If the bladder was very over-distended during blockage, some damage to the bladder wall may have occurred and only time will tell whether the muscles that produce normal emptying and squeezing down of the bladder will recover. Rarely, if extremely over-distended, tears can occur in the wall of the bladder, requiring surgical repair in another type of surgical procedure.

Once the obstruction has been relieved, cats will require at least a few days stay in the hospital. The urine is analyzed and cultured (to see if the urine contains bacteria) and antibioticswill be started if needed. Intravenous fluid therapy is provided as most blocked cats have dangerous levels of toxins in the blood and have bloodstream electrolyte imbalances that need to be corrected.

The veterinarian will leave the urinary catheter in place until it is less likely the cat will block again when it is removed. Spasms and pain will be attended to with medication, and sometimes tranquilizers are administered in order to relax an unhappy patient.

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed veterinarian. If you require any veterinary related advice, contact your veterinarian promptly. Information at is exclusively of a general reference nature. Do not disregard veterinary advice or delay treatment as a result of accessing information at this site.