I read your recent article about hyperthyroidism in cats. my mother has a 17 year old Maine Coon cat that weighs six pounds and displays many of the symptoms such as ravenous eating, (as much as 25 times a day), and roaming around night and day crying, etc.). the thyroid test came back yesterday from the local vet as a Level 3, considered normal. are there any other possibilities of disease or brain damage that would explain these symptoms and their correction?

Thank you for your time.

Based on the number value that you give for the thyroid test, I am figuring that your veterinarian ran a T4 blood test. the normal range for this test is 0.8 to 4. the T4 test can be used to diagnose hyperthyroidism, but T4 levels tend to fluctuate in the blood stream. this can lead to inconsistent results. It is possible to have a normal value and still be hyperthyroid. A more accurate test is the free T4 by dialysis. If the T4 test comes back in the high normal range and the cat is exhibiting symptoms of hyperthyroidism, the free T4 is recommended. There are also other thyroid tests that can be run that are even more definitive. I personally have acceptable results with the Free T4 by dialysis, but if there is still any doubt, other tests can be considered.

I think in your case it would really be worth your while to pursue the free T4. the symptoms you describe are very typical of hyperthyroidism. Also, don’t delay in getting this done, because if he is hyperthyroid, then his heart is working over time. Maine Coon cats are known for being prone to cardiomyopathy which is a disease of the heart muscle. Hyperthyroidism could be the straw that breaks the camel’s back. I realize at seventeen years old your mother’s cat has lived way beyond the normal life expectancy, but if the problem were hyperthyroidism, he might respond favorably to treatment.

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