Hyperthyroidism is a very common disease in older cats. It usually affects cats who are at least 10 years of age, and the average age of diagnosis is 13 years old. Many pet parents are surprised by the diagnosis, since the symptoms can be subtle and gradual. The good news is that hyperthyroidism in cats a highly treatable and manageable disease.

What is hyperthyroidism?

When the thyroid becomes enlarged, usually due to a benign, non-cancerous tumor, it produces excess hormones that can have an adverse and fatal effect on vital body organs, such as the heart. The thyroid is responsible for producing hormones that regulate vital functions, such as body temperature, blood pressure, heart rate, bowel function, and metabolism.

What are the symptoms?

Usually a heart murmur or fast heartbeat is the first clue to hyperthyroidism that your vet may notice. Afterward, your vet may order a blood test that checks for increased levels of thyroid hormone. However, at home, the symptoms can be much more subtle. Since the thyroid regulates so many aspects of a cat’s body, you may notice symptoms that include increased irritability, weight loss despite an increase in appetite, increased activity, increased drinking and urination, vomiting, and diarrhea.

How is it treated?

After diagnosis, your vet may recommend that you give your cat a pill, usually methimazole, two or three times a day. Methimazole in pill form is usually inexpensive and fairly safe, but other methods of administration include liquid suspensions and a gel that can be massaged into the back of your cat’s ear. One of the downsides of methimazole is that it has to be administered for life. It takes a few weeks to reach effectiveness, and ceasing the prescription can lead to a dangerous increase of thyroid hormone.

What are other treatment options?

Another treatment option is a radioactive iodine injection. It’s a more pricey treatment, and it involves hospitalization for several days while it runs its course. Since the thyroid uses dietary iodine to create its hormones, the radioactive iodine absorbs into the thyroid, thereby shrinking it permanently.

Building on the same principal, therapeutic veterinary diets have been recently developed that limit the amount of iodine your cat consumes. Lastly, surgery may be performed to remove your cat’s thyroid glands, so it’s always best to follow the advice of your vet when considering your cat’s unique circumstances.

If your cat has been recently diagnosed with hyperthyroidism, talk to your pet sitter about possible ways to pill your cat. Even the sweetest cats can become difficult when it’s time to take their medicine, so it’s best to schedule a meet and greet with your sitter to show how your cat prefers to be dosed.

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Candace Elise Hoes is a pet sitter and blogger at Katie’s Kitty. She is a graduate of the MFA Writing Program at California College of the Arts.

photo by PROMartin Cathrae on flickr