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Feline Hyperthyroidism was first described in 1979; about 2 years after the first pop-top cans of cat food were developed. It is actually associated with an abnormal immune response to the thyroid. It has been associated with feeding food from pop-top cans which are lined with a BPH containing substance (BPH is goitrogenic.) However, there are cats that have eaten only dry food who also have developed hyperthyroidism.


In the early 1970's, the only vaccines available for cats were feline panleukopenia, and rabies vaccine. Rhinotracheitis vaccine was developed around 1975. The first feline leukemia vaccine became available in 1985. Increasing elements in a vaccine are associated with increasing immune response, and some believe that this also has contributed to the problem.




Clinical treatments for cats with Functional Thyroid Adenomatous  Hyperplasia typically include the following three options:


» Daily treatment with an anti-thyroid drug (typically methimazole). The primary problem with this treatment is that it is not a cure. Treatment will be needed to be given every day (one pill given once or twice a day) for the rest of the feline’s life. Side effects may include vomiting, anorexia, fever, anemia and lethargy.



» Surgical intervention is another effective treatment using a procedure called a “thyroidectomy” (the removal of the thyroid gland). This option is usually selected when only one thyroid lobe is involved. While it offers a cure; it is possible for the hyperthyroidism to re-occur. A feline with kidney disease cannot have this surgery. A possible side effect is hypothyroidism (an underactive thyroid) which will require life-long thyroid supplementation.


»  Radioactive Iodine Treatment is a fairly new treatment that provides a permanent cure in 95% of all feline hyperthyroidism cases. A single injection of radioactive iodine ‘finds’ and destroys all the diseased tissue while sparing the healthy tissue.


1.There are no known serious side effects and minimizes stress to the feline.


2.The procedure is invasive and requires radioactive material to be put in your feline’s body.


3.Your cat must be isolated away from you for a few days until the radioactivity is gone.


4.This treatment is expensive – approximately the same cost as the surgical option.


5.A possible side effect is hypothyroidism which will require life-long thyroid supplementation.


Integrative Medicine


The following nutraceuticals or natural/herbal formulas can also provide effective treatment for felines living with Functional Thyroid Adenomatous Hyperplasia.


» Rehmannia Root (Cooked): An herbal root effective in treating auto-immune diseases in general and to also reduce hyperthyroid function.


» Cornus Fruit: A dried fruit pulp which helps balance an overactive thyroid.


» Poria Sclerotium (Hoelen): A mushroom that in many part of the world is used as a food instead of a medicine.


» And other herbal remedies such as: Dioscorea Root, Moutan Bark, Alisma Rhizome, Anemarrhena Rhizome, Phellodendron Bark, Kelp Thallus, Vervain Rhizome and Bugleweed Leaf.


Functional Thyroid Adenomatous Hyperplasia
– Feline Products –

(Reference: Veterinarians’ Desk Reference)

(Live Link)


Species affected: Cats.

Background: Occurs in older cats for unknown reasons. Recent studies suggest that sand/clumping cat litter and canned diets are risk factors. The lesion is either a hyperplasia or benign tumor of the thyroid, and the symptoms relate to an overproduction of thyroxine (not metastasis from a tumor, for instance). The syndrome is commonly associated with hypertrophic cardiomyopathy (also common in the cat in the absence of hyperthyroidism) and renal failure.

Symptoms: Increased appetite, rapid, pounding heart rate. If the disease is advanced enough, the appetite may decrease.

Diagnostics: Thyroid panel. Often the enlarged thyroid gland can be palpated.

Special Notes: Treatment is most successful when begun early.

Principles for Supplementation: Herbs that decrease the function of the thyroid gland, as well as Chinese herbs to deal with other signs. Do not judge by the thyroid panel alone, but also by improvement in symptoms. Track renal function, which often worsens when hyperthyroidism is brought under control.








Cats: ½-1 scoop/day

Inhibits thyroid, moisten tissues, decreases heat.


Cats: ½ capsule sid

If associated cardiomyopathy is present.


To help you quickly find the right Integrative Medicine formulas and manufacturers to help treat your dogs, cats and horses, please refer to the Veterinarians’ Desk Reference
(Click Here)




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