Feline Thyroid Disease

What is feline thyroid disease- What To Ask Your Vet?

Feline thyroid disease, also known as cat hyperthyroidism, is a glandular disorder found exclusively in felines. Cats have thyroid glands on both sides of the windpipe. The gland produces small amounts of the thyroxine (T4) hormone into the bloodstream. When excessive amounts are produced, a hyperthyroid condition results. The small nodules (adenomas) that form are almost always benign. There are a small number of hyperthyroid conditions that are caused by cancer. Veterinarians have reported that the occurrences of hyperthyroidism in cats have been on the rise over the last two decades. The reason why some cats are stricken and others are not is unknown, but it is suspected that many factors such as nutrition, environmental factors and immunology could play a role.

What are the symptoms?

One of the most common symptoms of hyperthyroidism in cats is weight loss. In fact about 95% of felines that come down with this condition lose weight. There are a number of other symptoms associated with this condition but the most frequent include increased hunger, vomiting, increased thirst, behavioral changes, hair loss and diarrhea. In some cases, cats can develop high blood pressure. If the condition is not treated, hypertropic cardiomyopathy (thickening of the heart) can occur. This almost always causes the cat’s heart to stop, which leads to death. Strays that have no pet owners and are not monitored for this condition almost always die.

What cats are at risk?

No cat is safe from hyperthyroidism. It can strike all breeds, male or female, but cats who have it are usually adolescent. The average of cats who see the onset of this condition is about 13. Very few under the age of 8 are stricken with the condition. There is no proof that any breed of cat is more susceptible to the condition than others.

How is hyperthyroidism diagnosed?

vet techsThere are three ways to diagnose the onset of hyperthyroidism: Clinical signs previously mentioned; palpitations found within the enlarged thyroid gland and increased thyroid hormone levels. There are occasions when an enlarged gland can be felt by hand, and it sinks into the chest cavity.  A physical examination by a veterinarian will determine if it is enlarged.

Veterinarians can monitor the elevated T4 levels via blood tests. It will be the responsibility of a vet tech to take a blood sample to see If the levels are elevated somewhat, checks will be made to see if the animal has concurrent conditions such as heart and kidney problems.

As added protection, CBC, urinary analysis and serum chemistry tests will be performed. Test results will determine the best course of action when the cat receives treatment. Cats with hyperthyroidism will show an increase in red blood cells, liver enzymes and creatinine. On some occasions, veterinarians will double-check their diagnosis by conducting a t-3 suppression test.

What is treatment?

There are three ways to treat hyperthyroidism in cats; they all have advantages and disadvantages: medical treatment with anti-thyroid drug; surgical removal of infected gland and treatment with radioactive iodine. The anti-thyroid treatment is the most popular of the three. It can be administered to cats in pill form or with a gel that is applied to the ear. The medication works by altering hormone gland synthesis. The good thing is the pill is relatively inexpensive, and it does not cause the parathyroid gland to lose function. The drawback with the anti-thyroid drug is that it is considered a therapy and is not a cure. There are side effects including nausea, vomiting and lethargy. Cats will also need to have check-ups every six months.

Surgery to remove the enlarged thyroid is performed when the thyroid has dropped into the chest cavity or if there is cancer present and it has metastasized. Although the cancer and gland can be thoroughly removed, there can be complications with this as well. Some cats develop nerve damage, kidney issues and laryngeal paralysis called Horner’s Syndrome.

Radioactive iodine therapy is a simple method where the thyroid is injected directly with iodine. The iodine kills overproducing cells without hurting organs. The disadvantages include cats having extended clinic stays due to the amount of radiation in their bodies, and clinics may not be local. This treatment may also not be a good option for cats with present medical conditions.