causes of hyperthyroidism cat
The causes of cat hyperthyroidism may include: 1  A high amount of benign cells in the thyroid gland, which is the most common cause of hyperthyroidism in cats. 2  These cells may cluster in small nodules on the thyroid gland; these nodules are known as adenomas.
Hyperthyroidism in cats is caused by an increase in production of thyroid hormones from enlarged thyroid glands, located on both sides in the cat's neck. In most cases, enlargement of the thyroid glands is caused by a tumor called an adenoma, which is almost always non-cancerous. The average age of cats with hyperthyroidism is 13 years of age; only about 5 percent of hyperthyroid cats are younger than 10 years of age.