My 12 y/o American Shorthair cat

Question
My 12 y/o female cat, Sassy, has been defecating outside of the litter box once or twice a day for weeks. The stool is always very soft and sometimes green in color, but usually yellow. I have tried everything I can think of to get her back on track. Since she is older and has arthritis issues (she limps alot hind quarters), I bought her a new litter box with a shorter entry, but she doesn't use it. I have been very vigilant in cleaning the 4 litter boxes (6 cats in house) daily. She has been to the vet and all her labs ( liver, kidney, and thyroid; no UTI) are essentially fine. The vet dewormed her since I had noted worms in some vomit and injected her with steroids for her arthritis pain. I've noted over the past few days that her stools now look as if they have oil in them. Also, they are mucousy and I have seen, on occasion, some frank blood in them. She has developed some foul smelling gas, too. She is also vomiting partially digested food maybe once a day. I still see her eating and drinking, though. So, she gets 1/2 baby aspirin (40.50 mg) once or twice per day. I was giving her some glucosamine/ chondrotin, but discontinued it since her limping was actually worse after 3 weeks of treatment. I just started giving her a 1/2 tab of centrine twice daily for diarrhea that I just observed today. Also, all the other cats are really terrorizing her. My sister's cats, who were living here when I moved here 15 months ago, always had their litter box in my mother's bathroom. I found it necessary to move it to another room in the house in which the other litter boxes are kept. But, the litter box misses had begun before this move. And, my sister moved out, but has been gradually moving her stuff out. So, things always seem to be going from one place to another in the house. Sassy had IBS as a kitten, but outgrew it. I have lost two other cats and another sister that lived here this year to cancer. That's all I can think of to tell you. Thanks in advance for whatever help you can offer.

Answer
Aspirin can be toxic to cats so I would stop that immediately. They cannot metabolize it the way humans can so it can be a real problem. We can use it for certain conditions such as in heart disease to prevent clots but even then we use an extremely low dose, usually every three days. Also, aspirin can cause bleeding of the gi tract so I am concerned about that. Lastly, never mix steroids and aspirin use. That can create real problems for the gi tract.

The gi signs you are describing could be from Inflammatory Bowel Disease or possibly a type of cancer called Lymphoma. You may want to talk to your vet about getting xrays and an abdominal ultrasound to further evaluate her. If these tests are all normal then endoscopy and biopsies may be the only way to assess whether she has IBD or Lymphoma.
Hope this helps.
Dr. G.