If your cat has been diagnosed with hyperthyroidism, don’t panic. Approximately 98% of all hyperthyroid issues are benign! Treatment for this disease is usually very successful; affected pets can live a long and healthy life with proper treatment.
There are three basic courses of treatment for hyperthyroidism in cats. Your veterinarian can help you pick the best treatment based on the age and health of your cat, chances for complication, and budget.
Radioactive iodine treatment is the most effective way to handle hyperthyroid disease in cats. The cat is injected with radioactive iodine that destroys all abnormal tissue and essentially cures the disease. The injection causes no damage to normal, healthy tissue — it only destroys the bad stuff. Afterwards, 97% of cats need no further treatment.
This treatment can be more expensive than other options, and your cat will need to be hospitalized for the procedure. After the treatment, you may need to take special precautions when handling cat waste, as it may contain radioactive materials. Your state may have specific regulations on how to handle this waste, but your vet will be able to advise you.
Surgery is another option for thyroid treatment. Your veterinarian can simply remove the affected thyroid lobe. This may be a risky choice for older cats, but cats who are in good health may be a good candidate for thyroid surgery. This may be a less certain option in terms of a cure — the surgeon may not be able to determine visually if only one lobe is affected. There may be thyroid tissue that is not in the expected location (known as ectopic thyroid tissue). With surgery, there is also a risk of damage to adjacent glands. It may take multiple surgeries to clear up a thyroid issue entirely.
Many owners choose to administer medication — methimazole — to control an overactive thyroid gland. Around eighty percent of patients respond well to drug therapy and have no adverse reactions to the drug. Methimazole works to tie up excess thyroid hormone so it isn’t used by the body. Side effects of the drug therapy can include digestion issues, lethargy, anemia, anorexia, and facial itching. In some cats, methimazole use causes a dangerous bone marrow suppression.
Your cat will need blood tests periodically to help regulate the medication dose. Choosing the medication route means your cat will need to take methimazole once or twice daily for the rest of his life. Methimazole is available as a tablet, a liquid suspension, and a gel that can be applied to the inside of the ear.
Which treatment is right for your cat? That is a decision for you and your doctor.