Thyroid Problems In Pets: What To Know And How To Deal With Them

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Thyroid-related issues, including hypothyroidism and hyperthyroidism, is common in the general human population. These conditions can cause a number of unpleasant effects on the human body and lead to a range of symptoms that may cause a disruption in the affected person’s daily life.

What many people do not realize is that the human body is not the only living organism that has a thyroid – both dogs and cats have thyroids that needs perform similarly to those in the human body.

Due to the various functions performed by the thyroid in both cats and dogs, it is important to understand that problems with the thyroid in these pets can lead to the development of conditions such as hyperthyroidism, as well as hypothyroidism.

In this post, we’ll take a look at what the thyroid does in your pet’s body and consider how various thyroid-related problems can affect a cat or a dog.

We’ll also provide an overview of the symptoms to look out for, consider how these conditions are diagnosed among pets, and finally look at the treatment options that are available to assist in reducing the severity of the symptoms that your pet might be experiencing.

Thyroid Function In Cats And Dogs

The thyroid gland is located in the same position within the human body and the body of your pet. The gland is located in the neck. Its specific location is close to what is known as Adam’s apple, and just behind the trachea. The gland forms part of the endocrine system, which is a system within the body that regulates the release of hormones.

The thyroid gland has a very important function in the endocrine system – it is responsible for releasing three specific hormones that all play crucial roles within the body. The three hormones that are released by the thyroid gland consists of:

  • Thyroxine, or T4 for short
  • Triiodothyronine, or T3 for short
  • Calcitonin

The first two hormones are often considered the primary hormones that are produced and secreted by the thyroid gland. They have functions to play in many different functions that occur in the pet’s body. Calcitonin is a hormone that helps the body to control the level of calcium that is present.

The thyroid gland is controlled by the Pituitary gland, which is also part of the endocrine system and sits at the back of the brain. The Pituitary gland is also referred to as the “Master gland” by many publications, as it is directly linked to the regulation of various hormones and controls many other glands that form part of the endocrine system.

The Thyroxine and Triiodothyronine hormones that the thyroid gland produces have a range of functions to play in the body of both cats and dogs:

  • Regulation of weight, including weight gain and weight loss
  • The function of the nervous system is regulated by these hormones
  • The hormones also play a role in the reproductive system
  • The skin is also influenced by the production of Thyroxine and Triiodothyronine
  • Body temperature is also regulated by these hormones
  • The metabolism of both carbohydrates and fats depend on a healthy secretion of T3 and T4 hormones

In addition to these functions, thyroid hormones also play a role in cardiac output, as well as heart rate. Muscle tone is also dependant on an adequate supply of thyroid hormones throughout the body of the pet.

Hyperthyroidism In Cats And Dogs

Hyperthyroidism is a condition that refers to an excessive number of hormones being present in the body of your pet. There are different reasons why this may occur, with a common reason being the thyroid gland becoming overactive – when this happens, an excessive amount of thyroid hormones are produced by the thyroid gland.

Numerous problems may develop in pets that are suffering from hyperthyroidism. Pet owners should be acknowledged about the potential symptoms that a dog or cat may experience and express when they have developed hyperthyroidism.

The two most common symptoms that pet owners would usually notice in their pet with hyperthyroidism is an increase in their appetite, along with a reduction of their weight. When this happens, then the pet should be checked at the vet to determine if they might be suffering from hyperthyroidism – and if not, to assist in the diagnosis of the specific condition that is causing the pet to experience these symptoms.

Apart from weight loss and the increased appetite, there are other symptoms that a cat or dog may also express when they develop hyperthyroidism:

  • The cat or dog may have excessive thirst – they may drink water excessively
  • The pet may seem to be hyperactive
  • The pet may also pant frequently
  • The body composition of the pet may change and look unnatural
  • The thyroid gland may become enlarged. This can be felt by placing your hand in the neck area – an enlarged thyroid gland sometimes causes a bump in the neck of the affected pet
  • The pet’s heart rate may be abnormal and may be rapid
  • Rapid breaking and difficulty breathing are also quite common in animals who have hyperthyroidism
  • Vomiting sometimes happens
  • Shedding may occur more frequently and may become more severe than usual
  • The pet may also seem to urinate more than usual with hyperthyroidism

It should be noted that there are cases where a pet may develop hyperthyroidism and experience a reduction in their appetite instead. This is often accompanied by weakness and signs of depression in the pet.

Hypothyroidism In Cats And Dogs

Hypothyroidism is the opposite of hyperthyroidism. While dogs and cats with hyperthyroidism have an excessive number of hormones circulating through their bloodstream, if your pet has hypothyroidism, they have a lack of these hormones in their body.

Hypothyroidism can also lead to a relatively large number of health problems in pets, which makes it essential for you, as a pet owner, to understand when you need to take action and get your dog or cat checked out for hypothyroidism.

Hypothyroidism is relatively rare in cats, but can still occur. In many cases, a cat would develop hypothyroidism after they have undergone certain types of treatments, such as surgery, for hyperthyroidism. The condition is more common in dogs. In general, hypothyroidism is not considered a life-threatening condition, but it can cause a range of unpleasant symptoms that might make your pet’s life more difficult.

One of the most common symptoms associated with hypothyroidism in pets would be an increase in their weight, usually without any specific changes in their diet.

Apart from the weight gain, it does seem that symptoms tend to vary between dogs and cats in some ways.

In cats, signs and symptoms of hypothyroidism may include:

  • The cat’s body temperature may be lower than usual
  • Their hair may seem matted
  • Constipation is relatively common
  • Inactivity is often observed among cats with this condition
  • Lethargy is also very common
  • As a kitten, you may notice a delay in the time it takes for their teeth to come out
  • Hair loss sometimes also occur in cats who suffer from hypothyroidism

While weight gain is a common sign of hypothyroidism, it should be noted that many dogs will first suffer from hair loss before they start to experience other symptoms of the condition. Apart from weight gain and hair loss, the dog may also experience these symptoms:

  • Their skin may be flaky, which can be accompanied by itchiness and sometimes also redness
  • The dog may seem sluggish
  • Their coat may seem dull and start to thin
  • The dog may experience an intolerance to cold temperatures
  • The dog’s heart rate may be reduced
  • Toenail infections are also more common in dogs with hypothyroidism

Diagnosing Thyroid Problems In Your Pets

Before a cat or dog can be treated for a thyroid problem, the specific condition they are suffering from the first need to be diagnosed. A vet will also need to determine how severe the condition is to ensure an appropriate treatment approach is taken to avoid potential side-effects

A physical examination by a vet is usually the first approach taken with the diagnosis of these conditions. The vet will also ask you about the symptoms that your pets are experiencing – this will help them determine if hyperthyroidism or hypothyroidism may be the issue, or rather another condition that should also be tested for.

In most cases, blood tests will be required in order to help the vet determine the level of thyroid hormones in the pet’s blood system. This will help them see if there are too many or too little of these hormones in their body, which will pave the way for a more accurate diagnosis.

With cats, a complete medical history will also be requested in order to determine if they might be at risk of thyroid-related issues.

Additional tests will often also be ordered, especially in cats, to help the vet identify any possible underlying factors that might have caused the condition.

Treatment Options For Thyroid Problems In Cats And Dogs

There are different ways that thyroid issues in cats and dogs can be effectively treated. Additionally, most of the treatment options that are available won’t be expensive and will be relatively safe for the pet to take.

In most cases where a dog is diagnosed with hypothyroidism, the vet will provide the dog with a drug that is administered orally in order to supplement the lack of thyroid hormones in their body. The most common drug that is provided to treat hypothyroidism in dogs is known as Levothyroxine, which is a type of synthetic thyroid hormone. The drug will be administered to the dog for the rest of their lives in order to avoid complications with the condition that they have been diagnosed with.

In cats, the underlying cause of the condition that they have been diagnosed with is usually targeted with the treatment plan that is developed for the pet. The same goes for dogs that have been diagnosed with hyperthyroidism. When the underlying cause of the condition is identified, then treating these issues will often result in a reduction in the symptoms and effects that hyperthyroidism has in the body of the pet – or, in the case of a cat, both hyperthyroidism and hypothyroidism.


The thyroid plays an important role in the endocrine system – not only in humans but also in our adored pets, including both cats and dogs. When the thyroid gland does not work correctly, it can lead to a number of unpleasant problems, including weight changes, issues with the dog’s energy level, skin-related issues, and more.

Understanding what symptoms to look out for can help pet owners identify these conditions early on, leading to a diagnosis before the condition becomes more serious. Treatments are available and will depend on the specific condition and severity of the pet.

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