A significant percentage of indoor cats are overweight or obese. Diets and weight loss in indoor cats are sometimes a long, frustrating and arduous process. That’s why, when many older cats suddenly start to lose weight, their owners are initially pleased. Unfortunately, it soon becomes obvious that the weight loss program didn’t suddenly become effective.
The thyroid is a butterfly shaped gland in the neck that produces a hormone that controls metabolism. In many senior cats (the average age of onset is 13 years), a benign tumor in one lobe of the gland causes overproduction of the hormone T4. Left untreated, the cat will burn off too much body weight and eventually suffer from heart and other organ problems. This disorder is referred to as hyperthyroidism, or overactive thyroid.
Weight loss, despite a voracious appetite, is the most obvious symptom of hyperthyroidism. Increased thirst and urination, vomiting and restlessness are also seen. The definitive diagnosis for hyperthyroidism is a blood test to measure levels of the hormone T4.
The good news is that this type of thyroid disease responds well to treatment.
Treatment options are:
Radioactive Iodine: a radioactive isotope of iodine is used to seek out and destroy the diseased portion of the thyroid gland. No further treatment is usually needed.
Oral Medication: Tablets, liquid or transdermal medication applied to the skin of the ear are used to block hormone production.
Surgery: Diseased parts of the thyroid gland are removed surgically. This type of treatment is more invasive and is usually only done where owners do not have access to radiation therapy.
Dietary: A prescription diet that is restricted in iodine is an option for some cats.