Diagnosing Cat Thyroid Problems

Cat thyroid problems affect your cat's endocrine system, which is responsible for a proper hormone balance within the body. There are two types of feline thyroid dysfunction: hyperthyroidism and hypothyroidism. Hyperthyroidism occurs when your cat's thyroid becomes overactive and produces too many thyroid hormones. Hypothyroidism occurs when your cat's thyroid is underactive and doesn't produce enough of the appropriate hormones. While these dysfunctions can make your cat seriously ill, they're easy to treat and aren't considered life threatening.

The Role of Your Cat's Thyroid

Your cat's thyroid gland is a small gland located in the throat. The thyroid plays an important role in your cat's body as a member of the endocrine system, along with the pituitary and adrenal glands. The endocrine system secretes hormones into your cat's body and is responsible for an appropriate balance of hormones within the body.

Feline Hyperthyroidism

Feline hyperthyroidism is far more common than hypothyroidism, and is in fact the most common feline endocrine disorder. Feline hyperthyroidism occurs when your cat's thyroid becomes too active and secretes too many thyroid hormones into the body. These are the hormones responsible for regulating your cat's metabolism.

Hyperthyroidism usually occurs as a result of non-cancerous enlargement of the thyroid gland, though as many as two percent of feline hyperthyroidism cases occur as a result of thyroid cancer. Cats can develop hyperthyroidism as young as age 4, but the average age of onset is about 13.

Symptoms of feline hyperthyroidism include:

  • Weight loss
  • Vomiting
  • Diarrhea
  • Tremors
  • Increased appetite and thirst
  • Behavioral changes
  • Dullness of the coat and hair loss
  • Weakness
  • Panting
  • Lethargy
  • Loss of appetite

Hyperthyroidism is diagnosed by the evaluation of three principal criteria. Your vet will first consider your cat's symptoms. He may palpitate your cat's throat to check for enlargement of the thyroid gland. Then he'll take blood from your cat to check for increased levels of thyroid hormones. Because the symptoms of hyperthyroidism can be identical to the symptoms of other serious diseases including diabetes, kidney and heart disease, your vet will perform blood and urine tests to rule out these possibilities.

Feline Hypothryoidism

Hypothyroidism is less common than hyperthyroidism and can occur as a result of hyperthyroidism treatment. Vets often have to experiment with dosage levels before they can restore the thyroid gland to an appropriate level of activity. A high dosage of thyroid suppressants may result in an underactive thyroid, which your vet can resolve by lowering the dosage. Hypothyroidism is also likely to occur in a cat who has undergone thyroid surgery, especially if all or some of the thyroid gland has been removed.

Symptoms of feline hypothyroidism include:

  • Weight gain
  • Loss of appetite
  • Thinning of the fur
  • Constipation
  • Slow heartbeat
  • Sensitivity to cold
  • Lethargy
  • Mental dullness

Hypothyroidism is diagnosed in much the same manner as hyperthyroidism, but your vet will check this time for lowered levels of thyroid hormones in the blood.

Treating Cat Thyroid Problems

Cat thyroid problems are easily treated with daily oral medication, though your vet may need to experiment in order to prescribe the right dosage. Hormone replacement therapy is quite effective and can restore your cat's normal quality of life.