She is now hypothyroid

We adopted Meg 2 years ago from CP, the day after she had a thyroid gland removed. She was found as a stray, very thin and was found to be hyperthyroid.

She was fine for about 18 months and then she started vomiting a bit and her coat started to look very scruffy and she just seemed generally not herself. We took her for a blood test and she had become hyperthyroid again. She was put on medictaion which made her itch and she scratched her face so much it was sore.

Our vet recommended radioiodine treatment which we decided to opt for and she had this in February this year. We were warned that it might not work or that she may develop an underactive thyroid (hypothyroid) but was told it was very rare.

Initially her thyroid level stabilised but then she got really lethargic and was sleeping all the time so we took her for another blood test which showed that now is is hypothyroid. This is apparently really rare in cats and only seen in cats who have had radioiodine treatment. My own vet has never had a case. So, in consultation with the vet who administered the radioiodine treatment she is now taking thyroxine drops. They are not licensed for use in cats as it is so rare.

She has been taking the drug for a month and has had a blood test. Her thyroid level has gone up slightly but when I spoke to the vet today he suggested doubling the dose to get her to mid range of normal.

So fingers crossed for her. She's been through so much. Does anyone else have a hypothyroid cat?

Hi there!

Sorry to hear about your cat! As you mention naturally occurring hypothyroidism is extremely rare in cats and is usually the result of over-medication or in some cases like yours, as a result of radioactive iodine treatment.

I think you'll find the best information on the following Yahoo group. Not sure if there are any hypothyroid cats on there at the moment but the people there are extremely experienced-a number have undergone RAI treatment.

feline-hyperT : A support list for people whose cats have been diagnosed as hyperthyroid (hypothyroid also welcome).

Hope your cat improves on the thyroxine treatment.

I am a congenitally hypothyroid cat. I have very short legs and a barrel chest. I was slow to mature. I really slowed down at around two yrs of age and became unable to walk. X-rays revealed my undeveloped skeleton. Blood tests revealed extremely low levels of thyroid hormone in my body.

Now, I take thyroid medicine daily. No big deal. I just have to get my thyroid levels tested annually to be certain I am getting the correct amount. I am now 6 yrs. old and live a very normal life.

Yes, hypOthyroidism is very rare in cats, esp. congenital cases, but it's not unheard of. Cats are usually hypERthyroid , while dogs are prone to hypOthyroidism. There are tell-tale signs of hypOthyroidism which are often overlooked or thought to be a manifestation of some other condition simply because it is so uncommon in cats. Please see my profile for more details about me.