Feline Hyperthyroidism
Problem: Hyperthyroidism is a common glandular condition in older cats (the average age of onset is 12 years) and occurs when there’s an excess of thyroxine-a (a thyroid hormone, also referred to as T4) in the bloodstream. Cats with feline hyperthyroidism are also at risk of developing heart disease, kidney disease, and hypertension.
Most cases of hyperthyroidism in cats are caused by enlargement of the thyroid glands. Rarely, the cause is a cancerous tumor on one of both glands.
Symptoms:
Treatment: Your veterinarian can diagnose hyperthyroidism with a simple blood test to check your cat’s T4 levels and prescribe a treatment that is best for your cat. Possible treatments include
Most cases of hyperthyroidism in cats are caused by enlargement of the thyroid glands. Rarely, the cause is a cancerous tumor on one of both glands.
Symptoms:
- Weight loss despite an increased appetite
- Overconsumption of food
- Increased thirst
- Increased urination
- Increased vocalization
- Vomiting
- Diarrhea
- Changes in activity level
- Increased shedding
- Unkempt appearance
Treatment: Your veterinarian can diagnose hyperthyroidism with a simple blood test to check your cat’s T4 levels and prescribe a treatment that is best for your cat. Possible treatments include
- Oral medication (Methimazole) - This medication blocks excess thyroid production but does not shrink the thyroid gland so it must be given over the duration of the cats' lifetime. It does have potential, though not common, side effects. Cats taking Methimazole should have blood tests every 3 to 6 months.
- Radioactive iodine therapy is highly effective and permanent. It involves an injection of radioactive iodine, which destroys the excess thyroid tissue. The downsides are that cats must be hospitalized for one week after injection, and may require hospitalization for a second week or isolation at home with minimal contact with humans, because their urine will be radioactive during this time.
- Surgery to remove the thyroid gland(s). This is an effective treatment, unless the cat has thyroid cells in other locations than the thyroid glands, as some cats do.