Hyperthyroidism in cats

An over-active thyroid gland is the most common hormonal problem that we see in our feline patients. It is in fact so common that about 1 in 10 older cats will develop this disorder.
It causes a cluster of classic symptoms; weight loss with a paradoxically increased appetite is typical. This is due to the increased metabolic rate from the excessive thyroid hormones. Other symptoms include increased thirst, restlessness, diarrhea, nausea, fast heart rate and ultimately heart muscle disease.
Diagnosis is relatively straightforward, blood tests to measure thyroid hormones will confirm the disease and often an enlarged thyroid gland in the cat’s neck can be palpated.
Treatment options are plentiful and often depend upon the age and health of the individual cat. Medications can be effective, they inhibit the hormone production and are available in tablet, liquid and even a trans-dermal ointment that can be rubbed on to the inside of the cat’s ears. They will be however be required life-long.
Surgery can be a good option for healthy or younger patients as it is relatively straight forward and can be curative. As with any anaesthetic and surgical procedure there are some inherent risks involved.
It is possible to control the condition by feeding an iodine restrictive diet. The diet needs to be strictly adhered to so indoor cats who aren’t fussy eaters tend to be the best candidates for this and it will again be life-long.
Finally it is possible to cure the condition by giving a carefully measured dose of radioactive iodine. It avoids surgery or ongoing medication and has a high success rate but requires a stay in a specialist Centre and is relatively expensive.
The best option for each cat depends on a number of factors so if your cat has this condition discuss with your vet which is the most appropriate treatment. Often times trialling the diet or medications first is sensible before embarking on a more permanent solution.