Hyperthyroidism in Cats
Hyperthyroidism is the clinical condition in which the thyroid gland produces excessive amounts of the thyroid hormones T3 and T4. Hyperthyroidism occurs in different species as the result of different mechanisms. In people, hyperthyroidism is relatively common and usually the result of an autoimmune disease called Graves’ disease named after the physician, Dr. Robert J. Graves. Graves' disease causes a diffuse enlargement, or goiter, of the entire thyroid gland3. In dogs, hyperthyroidism is a relatively uncommon disease that is usually caused by a thyroid carcinoma (i.e., cancer of the thyroid gland)4.
In cats, hyperthyroidism is almost always caused by one or more small benign tumors of the thyroid gland called adenomas5. These thyroid adenomas function autonomously and hence produce excessive amounts of thyroid hormones. The disease that causes hyperthyroidism in cats is similar to Plummer’s disease (named after the physician Dr. Henry S. Plummer) in people that is also caused by autonomously functioning thyroid adenoma(s)6. The clinical signs of hyperthyroidism are the same in all species and reflect the stimulatory nature of the thyroid hormones T3 & T4 on the cells of the rest of the body. Excessive thyroid hormone levels lead to an increased metabolic rate that if unchecked, ultimately proves life limiting.
Read Dr. Peterson's entire excellent article.
NB: This is a fantastic article by a world leader in veterinary endocrinology and true scientist (exploring all of the evidence while keeping an open mind). I had the honor of externing with Dr. Peterson at the Animal Medical Center in NYC when I was at Penn. At that time I was planning my academic career. My experience with Dr. P and other true scientists helped shape my career. As a result, I was able to fully embrace homeopathic and holistic treatment of the entire animal.