Hyperthyroid Disease in Cats
Hyperthyroidism is a relatively common endocrine disease affecting cats over 10 years of age. It is an illness which develops quite slowly, which can make it hard for a carer to spot. Routine health checks are especially important in older cats to try and help detect illnesses such as hyperthyroidism at the earliest possible stage.
Feline
Thyroid
Glands
All cats have two thyroid glands, one either side of the neck, below the larynx. The thyroid produces hormones that act on all of the cells of the body and are especially important in controlling the cat’s metabolism. Cats suffer from hyperthyroidism if their thyroid gland is producing too much thyroid hormones. It is usually caused by benign overgrowth of the thyroid gland(s) but very occasionally can result from a thyroid cancer (adenocarcinoma, < 2% cases).
Commonly reported signs of this illness include:
Weight loss: often in spite of a normal or even increased appetite
Vomiting and/or diarrhoea
Increased thirst and amount of urine produced: a carer may spot that litter boxes need emptying more frequently due to an increase in the volume of urine produced
Behavioural changes: including being more irritable/restless/clingy/’wired’, vocalising more
Coat changes, becoming dull and in poor condition
Fortunately, once diagnosed, there are several very effective treatment options for this condition.
Most cats diagnosed with hyperthyroidism can be managed very successfully and in some cases it is possible to cure the condition permanently. The ‘best’ treatment depends on each individual cat and owner situation. All treatments have benefits and disadvantages, which is why it is important that carers discuss management of their cat’s hyperthyroidism in detail with your vet.
Management options include:
Medication block the production of thyroid hormones and are lifelong treatment options:
Methimazole gel - this is a popular treatment option consisting of applying a topical gel to the inside of the patient’s ear daily.
Vidalta Tablets - this consists of tableting your cat once daily ongoing.
Iodine restricted food (Hill’s y/d): the very low iodine content of this food prevents the thyroid gland from being able to over-produce thyroid hormones
Potentially curative options
Referral treatment with radioactive iodine (radioiodine) which locally irradiates the abnormal thyroid tissue
Thyroidectomy - the surgical removal of the abnormal thyroid tissue by a procedure called a thyroidectomy
Dr Raewyn has developed her surgical technique for the removal of an overactive thyroid gland, over the past decade. This solution is a popular and cost effective option when consistent lifelong medical treatment may not be possible or fit the budget of the cat’s carer. A small incision is placed to the neck lower to the larynx, the muscle bellies are split to locate the enlarged thyroid gland. It is carefully teased away and removed. The surgery is minimally invasive and patients typically go home the same day. As with all surgery, there are risks, but these have been minimized by assessing if the patient is a good candidate for surgery and strategically planning what is the best option for every individual patient.
Even if a patient starts on one treatment path, we can adjust and switch to fit the patient and carer’s needs.
If you think your cat might have hyperthyroidism or if you cat is already on treatment but you interested in a change, please contact Omokoroa Pet Vets to discuss your options with Dr Raewyn.
