Recognizing and treating hyperthyroidism in cats

Posted: June 9th, 2017 | Featured, Lifestyle, Pets | No Comments

By Sari Reis

Is your senior cat eating more but losing weight? Has he shown an increase in thirst and a resulting increase in urination? Perhaps he has become hyperactive or his coat has become dull, matted and greasy looking. Is he vomiting or does he have diarrhea? If your kitty is displaying these clinical signs, it could be hyperthyroidism.

A cat suffering from hyperthyroidism (

Hyperthyroidism is when the thyroid gland, located at the base of the neck, over-produces a hormone that is released into the body in excess amounts. It is often caused by a benign tumor that develops. Since the thyroid gland controls metabolism, as well as having other functions, when it is out of sync, it can create havoc in the body. This disease has reached epidemic proportions not only in the U.S. but in Canada, Europe, Japan, Australia and New Zealand. Although hyperthyroidism can affect any breed or sex, it is more prevalent in cats over 10 years of age.

In a recent article in the New York Times titled “The Mystery of the Wasting House-Cats,” author Emily Anthes discusses how some scientists have narrowed down a possible explanation for this wide-ranging illness. They are Polybrominated diphenyl ethers (PBDE), common chemicals found in fire retardants that reside in our furniture, carpeting, and electronics and many other household goods that leech into the dust and air in our homes. These chemicals, which were originally used in the 1970s, were phased out by mid-2000. However, they can take decades to degrade and many products containing them could still exist in people’s homes. Since indoor cats seem to be more commonly diagnosed than outdoor cats or ferals, it is assumed these chemicals could be the culprit.

Diagnosing hyperthyroidism involves a physical exam, as well as blood tests and other diagnostic testing. If your furry feline is diagnosed with hyperthyroidism there are three treatments to consider.

The first treatment is medication. Anti-thyroid drugs can reduce the excess hormones being released by the thyroid gland but do not provide a cure. They are, however, easy to obtain and affordable. There can be side effects and treatment is usually lifelong dosing twice-daily. Routine blood tests will need to be done to evaluate efficacy.

The second form of treatment is surgery. A thyroidectomy, removal of the thyroid, has a good success rate. It will likely eliminate the disease and the need for medication. There are, however, risks with the surgery that must be considered.

Lastly, there is radioactive iodine treatment, which has become the treatment of choice. It is given by injection. It is 95 percent curative and is quite safe. There are no serious side-effects and it does not require anesthesia. Due to the radioactivity, the cat does need to remain in the vet hospital for 10 days to two weeks following the procedure to prevent radioactive contamination with humans. This procedure can be expensive ranging from $500 upwards.

Since many of the symptoms found in hyperthyroidism could be caused by other illnesses, it is imperative you have your kitty checked out so that a definitive diagnosis can be made.

—Sari Reis is a Certified Humane Education Specialist and the owner of Mission Valley Pet Sitting Services. For further information, you can contact her at 760-644-0289 or

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