Cats are masters of subtlety. They curl into quiet corners when they’re not feeling well, sleep a little longer, eat a little less or more, and rarely raise alarm bells. But what if those small changes are actually them calling out for help?
One of the most silent dangers out there is hypothyroidism. The condition affects everything from their energy levels to how their organs function. In this guide, we’re going to discuss everything there is about feline hypothyroidism, from what it is to how we can help our cats.
What Is Hypothyroidism in Cats?
Feline hypothyroidism is a condition that happens when the cat’s underactive thyroid gland doesn’t produce enough thyroid hormones, primarily thyroxine (T4). Because of this, their bodies will have significantly reduced metabolism, energy, and body temperature.
This often happens in older cats due to an overreaction to a previous hyperthyroidism treatment. Hypothyroidism is much rarer than hyperthyroidism in cats, but it’s still possible and dangerous.
What Are the Symptoms of Hypothyroidism in Cats?
As a result of the significantly reduced thyroid hormones, here are the symptoms to expect:
Unexplained weight gain. Cats with hypothyroidism may gain weight even if their diet and activity level have not changed. The slowed-down metabolism makes it harder for cats to burn calories effectively.
Lethargy or lack of interest in play. Along with a slower metabolism, the sluggish thyroid gland can leave cats feeling lethargic, tired, and uninterested in playtime.
Low body temperature. Feline hypothyroidism can also make cats feel colder because it reduces the body’s ability to regulate body heat.
Dry, thinning coat or excessive shedding. A cat with hypothyroidism can also have a much poorer coat quality. This coat will be considerably dry, brittle, and thin.
Constipation. Constipation is also a possible symptom of hypothyroidism in cats. Because they have a slower metabolism, their bowel movements will also be slower.
Mental dullness or "zoned out" behavior. Like their energy levels, they will also appear dull and zoned out.
Slow heart rate (bradycardia). Hypothyroidism in cats can also result in a much slower heart rate, reducing circulation and contributing to weakness.
Sensitivity to cold. Some can feel colder because of their impaired metabolism. You may see cats curling up in blankets and bedding.
Swelling in the neck (goiter). An enlarged thyroid gland can sometimes appear visible around the neck, but it’s quite rare.
What Causes Feline Hypothyroidism?
Feline hypothyroidism is caused by congenital and iatrogenic factors.
Congenital Hypothyroidism
This form is exceptionally rare and typically seen in kittens. It results from abnormal thyroid development or hormone production from birth. Congenital hypothyroidism in cats is associated with the recessive mutation in the TPO gene.
Iatrogenic Hypothyroidism
Iatrogenic hypothyroidism is the more common type of the two. This happens as a result of overtreatment for hyperthyroidism, which may include radioactive iodine therapy, bilateral thyroidectomy, or methimazole overdose.
Frequently Asked Questions
Get 150 AED Off Your Pet's First Visit
Subscribe to Our Newsletter
Worried about your pet?
We’re here for urgent care, wellness checks, or anything in between.
