Q MY cat has just been diagnosed with hyperthyroid disease.
The vet said this is very common in older cats but she would need to take tablets for the rest of her life, is this necessary? Are there any other options?
A HYPERTHYROIDISM (overactive thyroid glands) is a very common disorder seen most frequently in middle aged and older cats.
It is caused by an increase in production of thyroid hormones from the thyroid glands, which are situated in the neck.
Thyroid hormones are responsible for regulating many body processes, and when too much hormone is produced the clinical signs can be quite dramatic and cats can become seriously ill.
Fortunately, the vast majority of cats that develop hyperthyroidism can be treated very successfully and most cats will make a complete recovery.
In the vast majority of cases, hyperthyroidism is caused by a benign (non-cancerous) change in the thyroid glands causing too much thyroid hormone to be produced.
In affected cats, a wide variety of signs usually develop, often subtle at first, and become more severe over time as the underlying disease gets worse. As it is mostly older cats that are affected, some cats will have other diseases that can complicate and even mask some of the clinical signs.
The “classic” signs of hyperthyroidism are:
- Weight loss;
- Increased appetite;
- Increased thirst;
- Increased activity, restlessness or irritability;
- An increased heart rate;
- A poor and unkempt hair coat.
Thyroid disease is diagnosed by a simple blood test.
If your cat has thyroid disease there are four main treatment options.
The most commonly-used treatment option is tablets, which are given daily for the rest of the cat’s life.
These tablets are very successful in managing the disease but treatment does have to be monitored very carefully, so your cat will need a check-up and a blood sample every three months.
The second option is surgery. Surgery can provide a permanent solution to the problem by removing the thyroid glands. If both glands are enlarged they will most commonly be removed one at a time as there is a very important gland called the parathyroid gland attached to the thyroid gland that controls calcium levels in the blood. If this gland is damaged during surgery the consequences can be life threatening so each gland is removed individually to make sure there are no complications after surgery.
The third option is radioactive iodine therapy which requires referral. This is infrequently used and your vet will discuss this with you if it is felt to be the best option for your cat.
The final option is a special diet that is very low in iodine which limits the amount of thyroid hormone the body can produce.
The diet must be fed exclusively, ie no treats. The diet can be very successful but I have found a lot of cats don’t like eating it so owners have really struggled.
All treatments have pluses and minuses so your vet will go into much more detail and help you select the right treatment for you and your cat.