The Endocrine System - Guide to a Healthy Cat - page 183

is under too much continual stimulation and the muscle begins to
weaken. High blood pressure can also result from hyperthyroidism.
There are three accepted treatments for hyperthyroidism:
1. Drug therapy
2. Surgery
3. Radioisotope treatment
Each treatment has its pros and cons. A veterinarian should discuss
all the options and help you decide on the most appropriate course,
based on your individual situation. Once a cat becomes hyperthyroid,
it will always be hyperthyroid unless the overactive tissue is removed.
Drug Therapy
This is the least expensive option for treating hyperthyroidism, and usu-
ally means giving the cat methimazole twice a day. Most cats tolerate
this drug extremely well, but others can have side effects such as vom-
iting, bone marrow suppression and dermatitis.
To monitor for side effects and the effectiveness of the treatment,
a cat is started on a low dose of medication and then evaluated two
weeks later. At that time it is advisable to do a red blood cell count to
look for bone marrow suppression. Based on the results, the cat may
stay on the same dose or the dose could be modified. Cats are gener-
ally checked every two weeks until the thyroid level is in the normal
range.
Medical treatment will continue the rest of the cat's lifetime. It is
not the end of the world if an owner misses giving a dose every now
and then, but to be properly regulated, the cat must receive medication
regularly. Long-term medication costs and repeated follow up testing
will add up over years, so don't disregard other treatment options.
Take Them Out
Surgical removal of the thyroid glands can be a successful treatment.
Both glands are usually removed because it is difficult to tell if one or
both glands are affected without looking at the tissue microscopically.
The surgery involves the tissues of the neck and no body cavities are
opened. Once the thyroid is removed, it will not grow back. Some
glands have malignant tumors called thyroid carcinomas, which are dis-
covered when a biopsy is performed.