Hypothyroidism in Cats: Signs & Symptoms

While the words hyperthyroidism and hypothyroidism look similar and can cause confusion for concerned cat parents, these conditions are very different. Here, our specialty and emergency vets in Springfield share the hypothyroidism symptoms in cats, the different types they may experience and how it can be treated.

What is the thyroid gland?

The thyroid gland produces hormones that help regulate many processes in your cat's body, including metabolic rate. Cats have two thyroid glands located in their necks.

What is the difference between hypothyroidism and hyperthyroidism?

Hypothyroidism is a condition characterized by an underactive thyroid that does not produce enough of the hormones essential to maintaining a healthy metabolism. 

On the other hand, if your cat's thyroid produces too much thyroid hormone, your kitty suffers from hyperthyroidism.

Hypothyroidism is rare in our feline friends, unlike hyperthyroidism, which is fairly common in senior cats.

What causes hypothyroidism in cats?

While hypothyroidism is a common condition among humans and dogs, it rarely occurs spontaneously in cats. Hypothyroidism in cats is a result of over-treatment of hyperthyroidism, which is a more common condition affecting felines. This is referred to as iatrogenic hypothyroidism. The other two types are spontaneous and congenital feline hypothyroidism. We will go into a little more detail on each type below:

Iatrogenic hypothyroidism

Hyperthyroidism is typically treated in one of four ways: surgery to remove the thyroid glands, treatment with methimazole to reduce thyroid function, treatment with I-131 injections to destroy the gland, and finally, a low-iodine diet (as iodine is necessary for normal thyroid function). While most cats respond well to these treatments, their thyroid hormone levels may drop below the normal range, leading to iatrogenic hypothyroidism.

Spontaneous hypothyroidism

Spontaneous hypothyroidism occurs when the gland's function decreases without any identifiable causes. This condition, also known as primary hypothyroidism, is rare in cats, with only a few documented cases.

Congenital hypothyroidism

This type of hypothyroidism occurs when a kitten is born with a defect in the thyroid gland, reducing its function. A mutation in the TPO gene (which plays a central role in thyroid gland function) has been identified as a cause of congenital hypothyroidism.

What are the signs and symptoms of hypothyroidism in cats?

When it comes to hypothyroidism in cats, the signs and symptoms are caused by the slowing of their metabolism, which can result in the following symptoms:

Contact your vet immediately if your cat is displaying any of the symptoms listed above. While these symptoms can indicate hypothyroidism in cats, they can also be related to several other serious conditions that require veterinary attention.

Can hypothyroidism in cats be treated?

For many cats with hypothyroidism, no treatment is necessary. That said, if your pet's symptoms are severe, your primary care vet may prescribe synthetic hormone supplements and schedule follow-up blood tests to monitor your kitty's overall health and hormone levels. A modified diet containing reduced fat may also be recommended for your cat while they recover from hypothyroidism.

Typically, cats recover well from hypothyroidism, with a notable improvement in their health in a short time.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.