Q: My 14-year-old female shorthaired domestic cat lives strictly indoors. When she defecates, there’s a bit of blood at the end, a drop of blood afterwards. Her appetite is good and she seems to be her normal self. Earlier this summer, I brought a sample of her stool to the vet to have it analyzed and it came back normal. Why is she still having the bit of blood at the end of defecation?
A: When cats bleed from their stomach or small intestine, the blood gets digested. This turns the stool a dark, tar-like color. When cats bleed from their colon (large intestine), it is beyond the point where digestion occurs, so the blood comes out looking red, like blood. Because you’re seeing red blood, I believe it is coming from your cat’s colon. Your cat might have colitis.
Feline colitis has several causes, such as intestinal parasites, infection with giardia (a protozoan parasite), inflammatory bowel disease and stress colitis, to name a few. A 14-year-old indoor cat is unlikely to have intestinal parasites. The negative fecal test confirms that. I would make sure, however, that the fecal test also included analysis for giardia, as this protozoan can sometimes flare up and cause intermittent colitis and blood in the stool.
Try switching your cat’s diet to a high-fiber food. Your cat’s veterinarian can recommend a prescription diet designed for feline colitis. You may also want to try a short course of a colitis medication such as metronidazole and see if your cat responds.
My main concern is that your cat is 14 years old. Senior cats are at increased risk for cancer. Colorectal cancer is uncommon in cats, however, a tumor or growth in the colon or rectum has to be on the list of possibilities. If your cat doesn’t respond to symptomatic therapy — diet change and medication — you may need to have further diagnostics performed, such as a rectal exam, or colonoscopy, to determine the origin of the blood.