What is Hyperthyroidism in Cats?

Feline hyperthyroidism occurs when a cat’s thyroid glands produce an excessive amount of thyroid hormones. This condition is rare in dogs and most commonly develops in cats that are 12 to 13 years old. Thyroid hormones are involved with the functioning of many organs in your cat’s body; however, overactive thyroids can present problems.

What is Hyperthyroidism in Cats

What Can Hyperthyroidism Do to Your Cat?

Feline hyperthyroidism, also known as thyrotoxicosis, is most commonly caused by the overproduction of T3 and T4 hormones from enlarged thyroid glands in your cat’s neck. Nevertheless, in some cases, hyperthyroidism in cats can also develop due to non-cancerous or malignant tumors.

Since this condition can affect many organs in your pet’s body, overactive thyroids can cause a vast array of serious pet health problems. Some of the problems your cat may develop if it has hyperthyroidism include heart failure, high blood pressure, kidney damage, eye problems and even brain damage.

Common Symptoms of Hyperthyroidism

If your cat’s thyroid glands produce too many hormones, nearly every organ in its body can be affected. This includes the heart, liver, kidneys, digestive system, muscles and nervous system. As such, symptoms of the condition can vary greatly. Typically, signs will develop slowly and may include a few or many of the following symptoms:

  • Weight Loss and/or Increase in Appetite
  • Excessive Thirst and/or Increased Urination
  • Hyperactivity or Aggressive Behavior
  • Loss of Interest in Grooming and/or Increased Shedding
  • Greasy Coat
  • Panting
  • Diarrhea and/or Vomiting
  • Difficulty Breathing
  • Increased Heart Rate
  • Weakness and/or Depression
  • Fever
  • Lumps of Various Sizes Around the Neck Area

Typical Treatments for Feline Hyperthyroidism

Fortunately, there are many treatment options for hyperthyroidism in cats. However, one of the most common drugs administered to cats suffering from this problem is Methimazole, which can usually correct the condition in only two or three weeks. If you choose this option, administration of the medication is required for the life of your pet.

Another option is surgical removal of the thyroid gland. This option is typically preferred when the condition is caused by a benign tumor, also known as a thyroid adenoma. The most modern treatment method is radioactive iodine therapy, which is an injection that is effective in destroying the hyperfunctioning tissue. Unfortunately, while this method is quite effective, it is also the most expensive.

Of course, there are pros and cons associated with each of these treatment methods. As such, it is best for you to discuss each of these techniques with your vet to decide which one will be safest for your cat. Fortunately, when caught in its early stages, feline hyperthyroidism is quite easy to manage.

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