Understanding Hyperthyroid Disease in Cats


The good news is that if your cat is diagnosed with feline hyperthyroidism, your cat has likely lived long, as this is mostly a disease found in older cats – most often cats  in their teens, and nearly always in cats over 10-years old.

Feline hyperthyroidism is caused by an overactive thyroid gland that secretes excess thyroid hormone. Cats typically have two thyroid glands, one gland on each side of the neck. One or both glands may be affected. The excess thyroid hormone causes an overactive metabolism that stresses the heart, digestive tract, and many other organ systems.

Also, there’s often underlying kidney disease in many hyperthyroid cats – which is very important to know about.

If your veterinarian diagnoses your cat with hyperthyroidism, your cat requires treatment.

American Association of Feline Practitioners hyperthyroid cats with cat expert Steve Dale The question is what should that treatment be?

Over the course of the past few decades technology has offered new options.

Surgery still remains a possibility, but given that hyperthyroid cats are older and that other choices are now available, surgery is rarely done these days.

Instead, options include radioactive iodine treatment (it’s come down in price some and is more readily available than say five or 10 years ago, and may be curative), medication (means frequent veterinary visits to check thyroid levels and getting medication into the cat)  or a medicated prescription diet (which the cat must be on from now on, and no other food or treats are given).

The best choice depends on lots and lots of factors, all detailed in the new American Association of Feline Practitioners free cat owners’ education brochure Feline Hyperthyroidism.

One of many reasons to visit the veterinarian once every six months (especially for older cats) is that hyperthyroid cats often don’t appear ill, in fact, their appetites and activity levels may both increase – seemingly these cats may appear surprisingly youthful. The only way to really diagnose feline hyperthyroidism is a visit to the veterinarian.

Various other free cat owner brochures are available from the American Association of Feline Practitioners.