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Different Thyroid Problems in Cats [ Must Know ]

cat suffering with thyroid issue and laying sad

The thyroid gland is an endocrine gland that gives rise to thyroid hormones for the regulation of numerous metabolic activities in the body. Thyroid hormones are required for the continuance of usual, healthy activity levels of various body organs in your cat.

Cats possess a pair of thyroid glands, which are positioned ahead of the neck, under the larynx (voice box). The thyroid gland comprises of two lobes, one on both sides of the windpipe, and every gland is entirely penetrated in the pliable tissues of the neck that encircle the voice box.

Endocrine disorders like hyperthyroidism and hypothyroidism are usually not lethal and are curable. Both types of thyroid disorders are the consequence of a thyroid condition occur generally in older cats.


Hypothyroidism in cats

Although hypothyroidism is uncommon but serious, and is not a situation to take lightly. When the thyroid glands don’t produce enough hormone it’s known as hypothyroidism, or an underactive thyroid which results in a slower metabolic rate.

In cats, the most common reason for hypothyroidism is surgical removal or destruction (for example, by radioiodine or anti-thyroid drugs) of the thyroid gland as a treatment for hyperthyroidism.


Clinical symptoms of hypothyroidism in cats include

  • Weight gain (Obesity)
  • Messy hair coat
  • Loss of hair around the ears
  • Laziness
  • Low body temperature
  • Entangled hair


A medical history and thorough physical inspection are very essential for the detection of this disease. In addition to complete records there are also some medicinal tests that can be carried out by your vet. Some of these specific tests are

  • Complete blood count (CBC)
  • Urinalysis
  • also chest and abdomen X-Rays in a few particular cases

Your vet may also take other tests to prevent other complications.


In cats, normally no treatment is as such needed for hypothyroidism, as this condition is usually temporary in cats. The insufficient hormones are provided in synthetic form, with the dosage modified from time to time based on your cat’s physical situation. For cats that need thyroid hormone supplementation, a beginning dose of levothyroxine 0.075 mg twice a day is recommended by doctors but you must visit the vet and consult because taking any medicine without proper diagnosis can harm your cat’s health.


Hyperthyroidism in cats

Hyperthyroidism is the most frequent glandular complication in cats. It is caused by immoderate quantity of circulating thyroxine-a thyroid hormone usually known as T4-in the bloodstream. Mostly enlargement of thyroid glands result from a non-malignant tumor called an adenoma. Few unusual cases of hyperthyroid disorder are caused by non-toxic tumors known as thyroid adeno-carcinomas.


Cats affected with hyperthyroidism generally develop various symptoms that may be minor at first but become more harsh as the disease progresses.

  • Weight loss
  • Dyspnea
  • Vomiting
  • Increased level of appetite (polyphagia)
  • Increase consumption of water (polydipsia)
  • Restlessness
  • a tangled, slippery or poor hair coat
  • a rapid heart rate


Although the thyroid glands typically elongate with hyperthyroidism, this is not usually clear. Recognition of enlarged glands will demand a mindful palpation (inspection by touch) by your vet. Your veterinarian may extract some blood to perform tests and examine thyroid hormone levels. Radiographs and some additional tests may be conducted in order to make sure the health of your cat.

Technetium scan: This is a very modern test. This requires injecting a radioactive contrast medium into a cat, which will exhibit only the functioning part of the thyroid glands.

Total T4:  This is the most widely used test used to detect hyperthyroidism.  This value will be raised in almost 90% of cats with hyperthyroidism.

Free T4 by equilibrium dialysis: This is a more delicate test for diagnosing hyperthyroidism, and will catch 90% of the cats who were negative in the above-mentioned test.


cat treatment

There are three basic options for treatment of hyperthyroidism

  • Medication
  • Surgery
  • Radioactive-iodine therapy


Tablets or liquid medication can be used to control hyperthyroidism. The generally used and beneficial anti-thyroid drugs affiliated with a group known as thioamides. This comprises of both methimazole and carbimazole that are extensively used in the treatment of hyperthyroidism. Treatment is for the whole life, if you stop taking medicines, symptoms will come back again. Some cats may suffer from aftereffects, like vomiting, anorexia, Bone marrow suppression, temperature, jaundice, and Self-excoriation.

Radioactive Iodine (I131) treatment

This is the best possible treatment for hyperthyroidism and has a 96% possibility of a cure. The radioactive iodine is operated as a single injection, directly given deeply in the skin. The iodine is immersed and damage the abnormal thyroid tissue but does not harm the neighboring tissues or the parathyroid glands.


cat surgery

Deletion of the thyroid glands is an easy surgical process that has a high success rate. Surgery for removing the thyroid glands, also called surgical thyroidectomy, needs general anesthesia, and is hazardous for older cats.

Associated Diseases

Since altered levels of thyroid hormone have an influence on metabolism, they can be very harsh on many body systems and organs.  Some of the disorders that can be the result of hyperthyroidism are:

  • Chronic Kidney Disease (CKD): Hyperthyroidism is very damaging for the kidneys.
  • Thyrotoxic Hypertrophic Cardiomyopathy: Hyperthyroidism put a bad effect on the heart muscle, and will result in stiffening of the walls of the heart. 
  • Hypertension: Altered thyroid hormones can also result in high blood pressure. This may be irrecoverable, once the thyroid levels come back to normal.
  • Inflammatory Bowel Disease (IBD): Latest findings revealed that hyperthyroidism can stimulate the development of IBD.
  • Thyrotoxic Liver Disease: Elevated thyroid hormones can also be harmful to the liver.  Some cats will face liver failure in severe cases.

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