Signs of Thyroid Problems in Cats

The two primary thyroid problems in cats are hyperthyroidism and hypothyroidism. In hyperthyroidism, a cat's body produces too much of the thyroid hormone; in hypothyroidism, it produces too little. Of the two, hyperthyroidism is more common, but hypothyroidism can become an issue for cats after they have been treated for hyperthyroidism. For this reason, it's crucial for pet owners to closely monitor their cats after hyperthyroidism treatment.

Weight

Cats that have hyperthyroidism will have an increase in appetite that is accompanied with weight loss, sometimes dramatic weight loss. Cats that have hypothyroidism will tend to gain weight even though their food consumption has not increased.

Vomiting/Stools

Vomiting and diarrhea may or may not occur in cats that have hyperthyroidism. Cats with hypothyroidism seem more prone to vomiting and constipation.

Coat Changes

Cats with either type of thyroid problem can have dull coats, flaky skin and hair loss.

Behavior

Cats with hypothyroidism will have a decrease in activity and will sleep more often. They often seek out warm places to hide and rest. Things that would normally interest the cats will not excite them. Cats with hyperthyroidism are often restless and nervous, with higher activity levels. Both types of thyroid problems can produce aggressive behavior in cats.

Urination

Cats with hyperthyroidism will drink more and have more urine output.

Heart Rates/Strength

Hyperthyroidism produces faster heart rates in cats, along with labored breathing, tremors and weakness. Cats with hypothyroidism can also experience weakness.