By: Dr. Kerry Fost
The Cat Doctor Veterinary Hospital
For Pets Best Insurance
Feline hyperthyroidism is the most common endocrine disease affecting pets health in middle aged and older cats. It is a multisystemic disorder characterized by the overproduction of thyroid hormone.
The thyroid gland is located in the neck region and has an important role in regulating the body’s metabolic rate. With hyperthyroidism the gland becomes enlarged producing too much hormone and subsequently increases cats’ metabolic rate. The thyroid size increases most often due to a benign tumor. Less than 2% of cases involve a malignant tumor.
The prevalence of feline hyperthyroidism is increasing. In 1979 there was 1 reported case. From 1980 to 1990, 1 cat in 3,000 was found to have the disease. From the year 2000 on, it may be more common than 1 cat in 300. This increase is not thought to be just because of the increasing number of older cats. A specific cause has not been identified. The current theory is some type of environmental agent stimulates mutation of the regulatory proteins in the gland. Some of the environmental agents being looked at include, iodine in cat food, preservatives, pesticides, flame retardants in fabrics, heavy metals and plasticizers in non- stick can linings.
The most consistent finding with this disorder is weight loss, often with a good to ravenous appetite. With an increased metabolism the cat can’t eat enough to keep from losing weight. They also often have increased thirst and urination. Soft stool and vomiting may increase as well. Some cats have behavior changes with restlessness or changes in sleeping pattern. Hyperthyroid cats often have elevated heart rates and increased blood pressure. They may pant because they feel hot.
The diagnosis of feline hyperthyroidism is usually straightforward. It is made on the basis of typical clinical signs, the presence of palpable thyroid enlargement, and a high total thyroxin (T4) level in the blood. However, in some cats with mild hyperthyroidism, the diagnosis may be more difficult and require additional testing. Cat insurance can help to make this more afforable.
Treatment of the disease is usually successful. There are three choices for treatment; and any one of these could be the best choice in certain situations. Many factors must be considered when choosing the best therapy for an individual cat. These options include:
1) Oral or transdermal medication, usually methimazole, which ties up the excess thyroid hormone. This medication will have to be continued for the life of the cat.
2) Radioactive iodine treatment. This is a permanent cure but requires the patient to be hospitalized for several days at veterinary radiation treatment center. Not every state has a treatment facility available. And because this treatment can be expensive, it’s wise to research pet insurance so you’re prepared.
3) Surgical removal of the thyroid tumor. Surgery is less common than it once was due to potential complications.
Because this is a disease of older cats other concurrent diseases can complicate the prognosis. Most cats do well with treatment and the outcome is usually positive for both the owner and the cat. At present there are no known preventive measures, which why it’s a good reason to invest in pet insurance.