Kahler: Cat won't use litter box to defecate

Alice's 20-year-old cat has developed a nasty habit -- defecating outside her litter box.

The cat uses the box to urinate, but insists on defecating on the outside edge of the box. Because Alice did not provide the cat's name, we will call her Kelly.

Alice has changed the litter and washed the box but neither effort has made a difference. She is questioning whether Kelly may have senility and possibly forgets that she is supposed to use the box. Alice is frustrated with Kelly and the mess she's causing and is to the point of considering euthanasia.

Certain behavioral changes in felines and canines are called cognitive disorders. However, any physical disease process should be ruled out before we assign a behavioral diagnosis.

Kelly may have a change in her bowels causing a change in her defecation habits. There may also be a metabolic change that has led to this objectionable result.

A blood panel will assess major organ systems, including the liver and kidneys. Checking electrolyte levels and blood sugar can provide other clues. A radiograph of Kelly's bowel can help determine if there is an abnormality there.

Another consideration is the condition of Kelly's skeleton. Kelly likely has developed a bit of arthritis, which might be playing a role in Kelly's reluctance to get into the litter box.

I realize you're thinking that Alice told us Kelly was using the box to urinate, but defecation is a different function requiring different muscle use and skeletal positioning. It simply may involve too much discomfort for Kelly to climb into the box to defecate, then back out again.

If after a physical examination and some routine testing Kelly is found to be in good physical condition, then we should consider a mental/behavioral cause. As I mentioned, we do categorize some conditions in dogs and cats as cognitive disorders based on the limited types of testing we can perform on them. This is something Kelly would have to have done through her veterinarian, and if she is found to have a condition that fits this category, there are medical therapies that can be effective.

Defecation outside the litter box is objectionable, and I think we can all share in Alice's frustration. But if it's within Alice's means, Kelly deserves a chance at a diagnosis and, if feasible, treatment. She has been Alice's companion for two decades and perhaps that relationship can continue for some time to come.

Jeff Kahler is a veterinarian in Modesto. Questions can be submitted to Your Pet in care of LifeStyles, The Modesto Bee, P.O. Box 5256, Modesto 95352.