Feline Hyperthyroidism Symptoms and Treatments

The thyroid is a small gland found in the throat around the front of the trachea or windpipe, and is responsible for food metabolism and body organ function. In cases of hyperthyroidism too much thyroxine is produced and in many cases this is due to the growth of a small, non-malignant within the gland itself causing the increase in production. The reasons for the appearance of this benign growth are unclear.

It can occur in cats over one year old but it affects middle aged and older cats in the main. Its signs and symptoms are weight loss with an increased appetite (although, the reverse is true in a mall number of cases), vomiting and diarrhea, frequent and increased intake and output of water and a marked change in the cat's behaviour. He will become more active - hyperactive in many cases, and will often call and be far more skittish than usual. You may notice his eyes are kept wider than usual and that he reacts suddenly to stimuli.

High thyroxine levels need to be controlled and managed as they can affect the heart, and can cause cardiac problems such as a very fast heartbeat and possibly be a causative factor in the development of hypertrophic cardiomyopathy and other cardiac conditions. Kidney malfunction is a serious complication of high thyroxine levels and if this is present the treatment for hyperthyroidism will need to be balanced in order not to worsen the condition of the renal system. Your cat is also at risk from diabetes mellitus and dental disease.

Diagnosis is confirmed by blood tests, which will show a marked increase in thyroxin levels, and a thyroid scan which will show where a growth is present on the thyroid.

Depending on the severity of the condition there are three courses of feline hyperthyroid treatment open to the vet.

If your cat is suffering with associated kidney problems the vet will prescribe a drug such as Methimazole to lower the thyroxine levels, and this will need to be taken daily for the rest of the cat's life. The cat will need careful and regular monitoring for side effects and to assess the thyroxine levels over a period of time so that medication can be reviewed and altered if necessary.

If the cat is not suffering any kidney problems, the vet can either use an insertion of radioactive iodine to treat the benign tumour, which is implanted into the thyroid gland and removed after thyroxine levels have reached a satisfactory level, or surgically remove part of the thyroid gland to remove thyroxine producing cells. There is no harm caused to the cat in removing thyroid tissue, as the vet is simply removing enough tissue to compensate for the over-production of thyroid

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