Hyperthyroidism ranks as the most common glandular disease in cats, and typically affects cats 10 years or older. Cats with this disease may display some or all of these symptoms: increased appetite coupled with unexplained weight loss, irritability or nervousness, frequent vomiting, excessive thirst, diarrhea and lethargy.
Three treatment options are available: medication, surgery and radioactive iodine.
Medication involves twice-a-day doses of a drug called methimazole, available in pill or topical form. Cats receiving this drug must be monitored by veterinarians every few months to ensure that side effects such as vomiting, anemia or lethargy do not occur. The medication is designed to keep the disease in remission, but does not affect the tumor.
You can opt to have the thyroid gland surgically removed; however, complications are possible, including damage to the parathyroid glands located near the thyroid. In addition, cats with uncontrollable hyperthyroidism are regarded as potential anesthetic risks. Finally, the procedure needs to be performed by a surgeon skilled in performing thyroidectomies to ensure the thyroid has been completely removed without complications. Costs for anesthesia, surgery and post-operative care average $1,500, depending on where you live.
Radioactive iodine is regarded as the treatment of choice for curing this condition. It involves giving an injection of radioactive iodine (R131) under the skin. The iodine travels to the thyroid gland where it disrupts the function of the thyroid cells, preventing them from releasing excessive amounts of thyroid hormone thyroxine (T4). The T4 levels return to normal and the cat is cured. The cat is required by law to stay quarantined for a short period of time at veterinary specialty hospitals.
“In my opinion, radioactive iodine treatment is curative, non-invasive and very effective.” Said Arnold Plotnick, DVM, ACVIM, who operates Manhattan Cat Specialists in New York City and serves as medical editor for Catnip, a monthly newsletter affiliated with Tufts University’s veterinary school. “It is costly, usually between $1,200 and $1,600, but does not require post-procedure medication. This treatment is safe with a nearly 100-percent cure rate.”
By Sarah Zumhofe