Don't Turn Your Nose Up at the PU

Published: August 29, 2012
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"Dogpeople" recently asked, "Would you consider discussing the dreaded PU surgery in male cats? Ours had it, and ever since, he's a "new man" with magnificent unblocked streams of urine, lol!" For the uninitiated out there, PU stands for perineal urethrostomy, a surgery that can be a life-saver for male cats that experience recurrent urinary blockages.

Neutered male cats have very narrow urethras (the tube through which urine flows on its way out of the bladder), which puts them at high risk for becoming blocked when they develop lower urinary tract disease. Urinary crystals, stones, or "sludge" can be to blame, but in some cases involuntary muscular spasms alone are enough to completely close off the urethra.

Cats that are unable to urinate freely will usually spend a lot of time in the litter box but produce very little. As the condition progresses, the pain becomes excruciating. Toxins begin to build up in the blood stream and the bladder can even rupture. Without prompt treatment, a blocked cat will experience an agonizing death.

Emergency treatment involves draining the urine from the bladder, relieving the urethral blockage, dealing with biochemical abnormalities, providing a relaxing environment, fluid therapy, pain relief, and sometimes medications to relax the urethra and promote muscular contractions of the bladder.

Unfortunately, cats that have become blocked are at higher than average risk for developing the problem again. If preventive strategies (e.g., promoting water consumption, keeping litter boxes scrupulously clean, and providing environmental enrichment to relieve stress) fail to prevent the problem (or if it’s impossible to unblock the cat in the first place), it’s time to consider the perineal urethrostomy.

The PU surgery is radical. It involves removing the penis and creating a permanent opening in the urethra, subcutaneous tissues, and skin above the site of the blockage (I can picture the guys out there cringing). This shouldn’t stop you from considering a PU for your cat under appropriate circumstances, however. As "Dogpeople" said, her cat was a "new man" after surgery … and yes, he’s still a man. I take exception to comments about how this surgery makes male cats female in some way. The external appearance of male and female feline genitalia is pretty similar to the untrained eye, and these guys still have all their Y chromosomes.

In most cases perineal urethrostomies are very successful at preventing future blockages, but this is not the easiest surgery to perform. The feline urethra is so tiny it’s difficult to manipulate without promoting the formation of scar tissue that can obstruct the flow of urine, and some very important nerves reside near the surgical site. If you have any doubt about your regular veterinarian’s ability to perform this procedure, ask for a referral to a board certified veterinary surgeon.

It is important to remember that a PU does not deal with the underlying cause of the blockage, so if your cat has a history of idiopathic cystitis, bladder stones, etc. these problems will continue, just without the risk of urethral obstruction. Also, PU cats are at higher than average risk for urinary tract infections and so should be closely monitored with regularly scheduled urinalyses and/or urine cultures.

Despite these potential complications, a PU is a wonderful option for a cat that has experienced multiple or severe urinary blockages and is facing the possibility of euthanasia if his condition cannot be ameliorated.

Dr. Jennifer Coates

Image: Dmitry Berkut / via Shutterstock