Cat losing weight, high T4, drinking lots. Is it hyperthyroidism?

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Symptoms of hyperthyroidism (over active thyroid) in cats are: weight LOSS not gain, increased thirst and urination, increased hunger and vocalizing especially at night. They can have heart murmurs and arrhythmia. The side effects on not treating is heart disease and weight loss. I recommend treating if her T4 is above the high end of the reference range. Please feel free to post her blood work results. I hope this helps and I wish Sofi the best!

Good morning! It sounds as if Bunky might have diabetes, or kidney problems, or even an excessive amount of thyroid hormone (hyperthyroidism), based on the weight loss, and excessive thirst. Unfortunately, these are conditions that would need to be diagnosed by blood and urine tests, which would involve taking him to see his vet. Thyroid problems are very treatable with an oral medication, and diabetes is treatable with daily insulin injections, or sometimes just with a special food your vet can prescribe. At home, there isn't too much that you can do; I wish there was more I could suggest!

The main suspicion would be hyperthyroidism, he is showing all the symptoms, you need to take him to the vet ASAP in order to have a blood test done that should confirm this, then your vet can start him on a treatment for this condition (fully treatable).

The thyroid level can change in a month, especially if Dewey’s previous thyroid level was towards the middle of the normal range. There are also some other more specific tests that can be positive before the total thyroid hormone level increases. A few other diseases that can cause weight loss with a normal appetite include intestinal parasites, diabetes or occasionally certain types of cancer. If Dewey is continuing to lose weight I would recommend rechecking with your vet.

Poor Little Man! His lethargy, weight loss and excessive drinking make me concerned about several possible conditions, including kidney disease, hyperthyroidism, and diabetes, among others. At this point, he needs to be seen by his vet for an exam and lab testing (CBC, chemistry, T4 - thyroid) to evaluate his organ function. There isn't much that you can do at home without determining the underlying cause of Little Man's clinical signs.

It is fairly rare, but ask your veterinarian if your kitty may be suffering from Cushing's disease or liver disease. Also sometimes cats can still be hyperthyroid, even though the thyroid parameters are within normal limits (this is called euthyroid sick). He could also have a tumor. In any case, this needs to be investigated further.

These sudden changes in temperament and the weight loss are commonly due to an endocrine problem called hyperthyroidism. The thyroid starts working more than normal increasing the metabolism (that is the cause of the weight loss) and causing behavioural changes similar to what you described. A clinical examination at your local veterinarian is essential to confirm this clinical suspicion and treat appropriately. A blood test and urine analysis are needed. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!