[Baltimore Sun] Ask The Vet: Why is cat with thyroid condition losing weight?

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My car 13- to 14-year old cat Gator is eating wet food well. However, he is losing weight, sometimes throwing up and once, diarrhea. Gator is on medication for a thyroid condition.

— Dennis H., Frankford, Delaware

Hi Dennis, thanks for messaging me about your feline friend, Gator.

So, it sounds like Gator was diagnosed with hyperthyroidism by his veterinarian and you are currently treating the disease. However, Gator is still losing weight, vomiting and having occasional diarrhea.

If Gator were my patient, the first thing I would do is recheck his thyroid values. Two of the most common signs of hyperthyroidism are vomiting and weight loss. Even though you are currently treating him for the disease, it is possible that the dose of the medication needs to be increased to better regulate his levels.

Now, if thyroid values have been checked and are normal, full blood work would be an appropriate next step. This will allow your veterinarian to evaluate Gator for kidney disease (among others), which is a common age-related disease in cats that can be masked by uncontrolled thyroid disease and that can also cause vomiting and weight loss.

Finally, if blood work is normal, I would consider an abdominal ultrasound to evaluate Gator’s abdomen for any potential tumors or cancerous changes. Gastrointestinal lymphoma is a disease we often see in our elder feline patients that can absolutely contribute to weight loss as well as cause vomiting and diarrhea. Please let us know how he gets on.

Ask The Vet is a weekly series by Dr. Devon B. Smith, a Baltimore veterinarian who is an associate at Madonna Veterinary Clinic in White Hall. Send your pet questions or photos via the forms below.