The thyroid glands rest on each side of the neck. These small glands secrete thyroid hormone to regulate the body’s metabolism. Middle aged and older cats may develop a benign (non-cancerous) enlargement of the thyroid gland known as hyperthyroidism; cancer of the thyroid gland is rare in cats. The cause of the overactive thyroid gland remains a mystery. The enlarged thyroid gland produces excessive amounts of thyroid hormone resulting in an increased metabolic rate in the body. To compensate for the increase in metabolism, the heart must work harder and pump blood faster to deliver more oxygen to the tissues for energy. Cats with hyperthyroidism develop a voracious appetite with weight loss, vomiting, diarrhea, excessive thirst and urinations, and behavioral changes. Physical examination findings reflect the effects of the increased metabolic rate: an elevated heart rate and blood pressure; a heart murmur may develop. Treatment options for cats with hyperthyroidism include: medical therapy to inactivate the thyroid hormone, radioactive iodine therapy, and surgical removal of the thyroid glands. Your veterinarian will discuss with you the best choice for your cat.

• Hyperthyroidism