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Felinexpress.com Home > Cat Health > Feline Hyperthyroidism

Feline Hyperthyroidism

Not to be confused with Feline Hypothyroidism, Feline Hyperthyroidism is the over-stimulation of the thyroid gland. The thyroid gland is located in the base of the cat’s neck and responsible for releasing hormones into the body. These hormones help to control the cat’s metabolism (the rate in which food and oxygen is used for energy). In some elderly cats these glands become enlarged. A toxic goiter is formed and hormones explode from the glands. This condition turns into cancer, most cancers stay benign, but in one of thirteen cats, the cancer metastasizes. The causes of this condition are unknown but some of the risk factors appear to be:

Causes of Hyperthyroidism:

  • Diet is a factor, being fed a canned cat food diet especially food containing turkey and giblets puts cats at risk
  • Exposure to cat litter
  • Kidney issues
  • Exposure to second-hand smoke
  • Exposure to household chemicals
  • Over-vaccinating your cat

Signs Your Cat May Have Hyperthyroidism:

  • Increased appetite
  • Drinking more water and frequent trips to the litter pan
  • Energetic activity
  • Weight loss
  • Restlessness, pacing, yowling
  • Short bursts of aggression
  • Sense of smell affected- starts eating odd food items not normal for the cat
  • Oily coat, claws become longer
  • Hair loss
  • Vomiting and diarrhea


If Hyperthyroidism is suspected based on the results of a CBC, your vet will order another test, a thyroid scan. Your cat will be injected with a small, mild, radioactive material and within twenty minutes you will have your answer. The radioactive isotopes are tracked within the body. If the scan reveals a glowing cluster, the tumor is benign. If that glow is spread out throughout the cat’s body the cancer has metastasized and further surgery will be discussed.

How to Treat Hyperthyroidism:

It is a three-tiered treatment-either conventional medicine, Tapazole or Methimazole are the most commonly prescribed. Surgery or radioactive treatments are additional options.

Cats can have an adverse reaction to Tapazole in pill form so ask your veterinarian if it can be compounded

Radioactive Iodine treatments- no anesthesia required the treatment is an injection under the cat’s skin.

Once your kitty undergoes radioactive treatment, he will have to stay secluded in the treatment center until he no longer sheds radioactive waste. This can be anywhere from one week to a month.

Natural Remedies:

Changing your cat’s diet to Dr. Pitcairn’s Cat Allergy Diet is one option. You can find this diet on Page 297 of his book; Dr. Pitcairn’s Complete Guide to Natural Health for Dogs and Cats Third Edition- Dr. Pitcairn advises his patients to go the conventional route of medications first and then if symptoms persist, consult with a holistic veterinarian for further options.


The earlier the disease is caught, the better the outcome will be. Life expectancy especially in the benign cases shows good results. Having an early CBC done at the vet establishes a baseline of health of your cat. If you suspect kitty might be ill, subsequent CBC can be compared to the initial blood work and map out any problems. Once diagnosed, monitoring kidney values becomes a crucial part of your cat’s care. Most cats are easily treatable and go on to live happy lives with their owners. Your cues lie in your cat’s behavior. By watching for subtle or sudden changes in your cat and acting accordingly, you will increase your cat’s chances to survive this disease.

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