Dear Doctor – A gastrointestinal disorder in cats

Letter to Tufts Veterinarians


Q My cat Romeo is 2-1/2 years old, and he has bloody, soft stool with mucous in it. This problem has been going on since he was a kitten. He has been on Albon three times, which helps clear it up and firm the stool. After being off the Albon for about ten days, however, the problem returns.

The last time his stool was tested for blood and parasites, it showed that he had coccidia. He was then put back on the Albon for two weeks, and his stool later showed no parasites. Unfortunately, he still has soft, bloody stool with mucous in it.

Our vet is concerned that it might be a polyp, but this will require further testing and we haven’t reached that stage yet. Any advice would be appreciated.
Autumn Layman

A Dear Autumn: Large bowel diarrhea (otherwise known as colitis) in young cats can have several causes, and I will address the two most common in response to your letter. The first is a parasite called Tritrichomonas foetus. Diagnosis of this parasite via PCR testing of the stool seems to be best, and treatment with a special antibiotic would be required.

The other cause is dietary intolerance, sometimes referred to as “food allergy.” Some ingredient — be it chicken, beef, fish, wheat or something else — is not tolerated and causes diarrhea. The only way to diagnose this condition is through the feeding of special diets containing unique ingredients that your cat has never before eaten. Although limited ingredient diets are available without prescription, the diets with the best chance of success must be purchased through your veterinarian. The choice of the diet should be based upon what foods Romeo has eaten since he was a kitten, and careful review is important.

Therefore, my recommendation is to bring a fresh stool sample to your veterinarian and request a PCR test for Tritrichomonas foetus. If this test is negative, a hypoallergenic food trial should be performed, preferably under your veterinarian’s supervision. If neither of these result in a cure, you may consider referral to a veterinary specialist in internal medicine to look for even less common causes.

Best of luck to you and your pet!

Michael Stone, DVM, ACVIM
Clinical Assistant Professor
Cummings School of Veterinary
Medicine at Tufts University


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