Overactive thyroid disease in the cat


This is a common disease in middle aged and older cats. It is technically known as hyperthyroidism

cat2The two thyroid glands are oval shaped and lie one on each side of the trachea (windpipe) on the underside of the neck. They produce thyroxin (thyroid hormone), which controls the speed of the cat’s metabolism.

In hyperthyroidism the thyroid glands are benignly (not cancerously) enlarged and produce excessive amounts of thyroid hormone. The enlarged glands can often be felt and are called goitres.

Hyperthyroidism is a common condition of middle aged and elderly cats. Due to excessive stimulation of the heart hyperthyroidism can eventually cause heart failure.

  1. Increased thirst
  2. Increased hunger
  3. Weight loss
  4. Poor coat condition
  5. Diarrhoea
  6. Increased yowling and feisty behaviour
  7. Over-activity – an old cat will often seem much more active, stressed and anxious than normal. Occasionally cats will be lethargic and very inactive instead.

Please Note: Not all hyperthyroid cats will show all these signs.