Are My Cat's Digestive Troubles Simply Part of "Growing Old?"

Q: My 19-year-old cat’s digestive behavior has changed dramatically in the last few months. She went from constipation to daily vomiting and diarrhea. Her appetite is ravenous and she can’t to drink enough water to satisfy her thirst. I do not believe the condition is parasitic; the four other cats in the house show no symptoms of this.

My vet believes this comes with being an elderly cat and not disease or infection. Her hearing is mostly gone, her eyesight is clouding, her mobility is still good even though she is obviously arthritic, but she responds enthusiastically to affection and, being part Siamese, meows at the top of her lungs at all times (we think because she can no longer hear herself). 

This is the oldest cat I’ve owned. Am I doing my elderly cat a disservice by letting this continue?  I am too close to the situation to decide from a realistic viewpoint.

A: Your cat shows clinical signs that fit with a number of common illnesses that affect older cats, such as diabetes and hyperthyroidism.
Kidney failure, a common illness in older cats, can cause vomiting and weight loss, but usually causes poor appetite and doesn’t cause diarrhea. Diabetes causes excessive thirst and urination, and usually a ravenous appetite, but rarely causes diarrhea. It is also unlikely to develop in a cat this old; it tends to be more of a middle-age disease.

I would place my bets on hyperthyroidism, a condition commonly seen in older cats. In this condition, the thyroid gland in the neck makes too much thyroid hormone, which causes cats to lose weight and have a ravenous appetite. Some cats will have other clinical signs, such as excessive thirst and urination, vomiting, and diarrhea. Blood tests easily can diagnose hyperthyroidism, which is very treatable. 

If your vet thinks that this is all a part of old age, go to another vet. If, however, blood tests do not reveal the cause of your cat’s excessive thirst and urination, ravenous appetite, diarrhea and weight loss, then a gastrointestinal disorder such as inflammatory bowel disease or gastrointestinal lymphoma should be considered, and I would understand if you were reluctant to pursue the advanced diagnostics required. In this case, your vet could at least offer symptomatic therapy for the vomiting and diarrhea; many drugs can address these issues.

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