Feline Hyperthyroidism Treatment Explained

Feline hyperthyroidism is the most frequent endocrine disorder that occurs in cats. When the circulating levels of thyroxine and triiodothyronine (two of the hormones secreted by the thyroid gland) increase, a multisystemic disease starts developing. Identifying the symptoms and getting the diagnosis confirmed are preliminary steps to following a treatment.

Occurence of Feline Hyperthyroidism

Feline hyperthyroidism is most common in middle-aged and old cats, regardless of breed and sex. The gravity of the symptoms is not always the same, so while some cats may display extremely mild clinical signs, other may feature dysfunctions of many organ systems. Multiple organ failure appears as a result of the multisystemic effects of cat hyperthyroidism.

Clinical Signs and Symptoms

This cat thyroid disease is characterized by such symptoms as:

  • Weight loss
  • Hyperactivity
  • Increased appetite
  • Increased water consumption
  • Frequent urination
  • Intermitent vomiting
  • Diarrhea
  • Increased heart rate
  • Arrhythmia
  • Congestive heart failure
  • Enlarged cat thyroid gland

A variation of common hyperthyroidism, which is present in around 10 percent of the cats, is called apathetic hyperthyroidism. This type of endocrin disorder has a few characteristics. For example, hyperactivity and increased appetite are replaced by lack of appetite and depression. More than that, the cats that suffer from this variation of the disease will lose weight more rapidly.

How Cat Hyperthyroidism Is Diagnosed

Measuring the circulating hormone levels is not enough when diagnosing cat hyperthyroidism. Planar thyroid scintigraphy, also known as thyroid imaging, is a far more accurate way of determining whether your cat suffers from this endocrin disease. Hyperfunctional thyroid tissue can be easily detected when using this procedure.

Therapy Options for Your Pet

Once the diagnosis is confirmed, the veterinarian will decide which treatment is best for your cat. The available options are:

  • Antithyroid drug administration
  • Surgery
  • Radioactive iodine

Methimazole (Tapazole) is among the most common drugs used for blocking the production of hormones. If the veterinarian opts for antithyroid drug administration, you need to know that the treatment is lifelong, and that the symptoms will start reappearing as soon as you stop administering the drug.

Surgical thyroidectomy is a cat surgery procedure that implies reducing the size or total removal of the gland. This treatment method has major downsides, as the anesthetic and the complications that may appear during or after the procedure typically lead to death. Complications that are usually observed after the surgical intervention include:

  • Persistent hypothyroidism
  • Laryngeal paralysis
  • Horner's syndrome
  • Hypoparathyroidism

In more than 70 percent of the cats, both lobes of the gland are affected by this disease, so the removal of the entire gland is mandatory.

Radioactive iodine therapy focuses on treating damaged thyroid tissue. The procedure takes from 3 days to a week, period in which the pet needs to be hospitalized. Since this treatment option provides the best results, it is preferred by most of the vets. There are no fatality risks, and more than that, no adverse reactions have been noticed. Anesthetics are not required and the results are more than promising, reductions of hormone synthesis being observed in more than 95 percent of the cases.

Since hyperthyroidism is quite frequent among cat diseases, having your pet diagnosed and treated as soon as possible is highly recommended. Even though all three methods are somehow effective, it is best to go for radioactive iodine therapy, because this one has no serious downsides.