There are four main types of treatment for cats with hyperthyroidism. But every cat is different, so your vet will be able to advise the best course of action for your feline friend.
Oral medication
Anti-thyroid drugs slow down your cat’s thyroid glands so they don’t produce and release as many hormones. These are most often taken twice daily, which can be difficult to keep up with, especially as it’s a lifelong treatment. Your cat will also need regular blood tests done for the rest of their life. This is to make sure the medication is working and not having negative side effects on their kidneys.
Outlook
Treatment with anti-thyroid medication can be adjusted depending on how effective it is. Your cat should experience a reversal of any hyperthyroid symptoms for as long as they stay on the medication. If you stop the medication, or give too low a dose, the symptoms will come back.
Surgery
Surgery – called a thyroidectomy – involves removing the enlarged gland tissue. This can mean a permanent cure (or at least a long-term cure) as the tissue is no longer there. It can re-develop later down the line if any remaining tissue becomes infected.
With surgery comes risks as your cat will have to be put under a general anaesthetic. So it might not be the best route for older cats or those with additional health needs. There’s also the possibility of damaging the parathyroid gland which sits right next to the thyroid. This might leave your cat needing lifelong treatment for low calcium levels, and this medication is expensive. Another risk with surgery is that removal of the whole gland can cause thyroid levels to drop too low, and supplementation with tablets are needed.
Outlook
After surgery your cat shouldn’t show any signs of hyperthyroidism. There is a small risk that if just one gland was removed that the other gland may show signs later down the line. Your cat still needs to have regular blood tests to make sure their thyroid hormones stay at normal levels.
Radioactive iodine therapy
Radioactive iodine therapy may sound daunting, but it’s a safe and effective treatment.
A vet injects a small dose of iodine under the skin, which is absorbed directly by the thyroid without affecting other organs. This targets and inactivates the overactive thyroid tissue.
For most cats, a single injection can provide a long-term cure. While not all vet clinics offer this treatment, your vet can refer you to a specialist clinic within a reasonable distance.
Outlook
Many cats experience a complete reversal of symptoms after one radioactive iodine injection and can go on living their adventurous lives. Occasional blood tests may be recommended to check symptoms have not returned.
Dietary therapy
Another treatment for hyperthyroidism is a low iodine diet, which prevents the thyroid from becoming overactive. This is usually available on prescription from your vets.
Outlook
If your cat is fed an exclusively low iodine diet, then they shouldn’t show symptoms of hyperthyroidism. If you change their diet, then symptoms may come back.
If they are a hunter, or snack on anything other than their special diet, a low iodine diet may not be enough to control their thyroid levels.
This treatment is normally best suited to indoor cats. As with medications, regular blood tests are recommended to make sure the thyroid hormones are in the normal range.