Hyperthyroidism is common in middle-aged and senior cats. The signs of hyperthyroidism may be confused with other diseases. Learn what to watch for and how hyperthyroidism is diagnosed in this FAQ.
Common signs seen with hyperthyroidism
Cats with a overly active thyroid gland usually have a increased level of metabolism.
Common signs include:
- weight loss, often despite increased appetite
- increased appetite
- increased activity
- increased thirst and urination
- increased vocalization
- vomiting and diarrhea
- always "hot" -- seeking cooler temperatures
- fast heart rate
Clinical signs seen vary with each cat. Many of these signs may be seen with other common senior cat diseases, such as diabetes mellitus and kidney failure. In some cases, more than one disease process may be present, for example kidney failure and hyperthyroidism.
Diagnosis of hyperthyroidism
Sometimes a thyroid nodule can be palpated in the neck. This is not a definitive diagnosis however. The primary way to diagnose hyperthyroidism in cats is by a blood test. The T4 levels will be elevated in a cat with hyperthyroidism.
Age and other diseases may suppress T4 levels, making diagnosis more difficult. For those cases, there are a multitude of specialized tests, primarily Free T4 and the T3 suppression test. Nuclear medicine thyroid scans are also available to diagnose this disease.
Treatment of hyperthyroidism
There are three treatment options for cats:
-
1) Medication - methimazole.
2) Surgical removal of the thryroid tumor - called a thyroidectomy.
3) Radioactive iodine therapy - selectively destroys hyperactive thyroid tissue.
4) Prescription Y/D Diet
Learn the pros and cons of each treatment method: Hyperthyroid Treatment Options
