Hypothyroidism in Dogs - Causes, Symptoms and Treatment

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Hypothyroidism in dogs is a disease caused by the improper functioning of the thyroid gland and the consequent decrease in the production of thyroid hormones. Hypothyroidism causes very varied and very unspecific symptoms. The positive is that it can be easily treated, although it is a chronic disease.

In this AnimalWised article we will explain the symptoms, causes and types of canine hypothyroidism, as well as its diagnosis and treatment. If you suspect that your four-legged friend may be suffering from this disease, read on to find out all about hypothyroidism in dogs.

You may also be interested in: Hypothyroidism in Cats - Symptoms and Treatment Index
  1. What is canine hypothyroidism?
  2. Causes of hypothyroidism in dogs
  3. Types of hypothyroidism in dogs
  4. Symptoms of hypothyroidism in dogs
  5. Diagnosis of hypothyroidism in dogs
  6. Treatment for hypothyroidism in dogs
  7. Diet for dogs with hypothyroidism

What is canine hypothyroidism?

Hypothyroidism in dogs is a disease that causes a deficiency in thyroid hormones which is responsible for producing the thyroid gland, located in the throat, below the larynx. The hormone called T4 or thyroxine it is the one that controls the metabolic rate of the organism. Therefore, a decrease in the amount of this hormone in the blood will have consequences on the dog's metabolism, which is decreased, which translates into a large number of non-specific symptoms..

Causes of hypothyroidism in dogs

Any problem that affects the functioning of the thyroid gland can cause this disease. Thus, canine hypothyroidism can occur when the dog's own immune system attacks the thyroid gland and damages or destroys it. It can also be due to a degenerative problem in which the gland tissue is gradually replaced by adipose connective tissue. An abnormal growth of cells in the thyroid gland is another less common cause. In a smaller number of cases, hypothyroidism does not occur due to a problem in the thyroid, but in the pituitary, which regulates the production of T4.

Although dogs of any age can suffer from hypothyroidism, the disease is more common in middle-aged dogs of medium and large breeds. Any dog ​​can suffer from the disease, but it is more common in:

  • golden retriever
  • Doberman
  • labrador retriever
  • boxer
  • dachshund
  • Cocker spaniel
  • beagle
  • airedale terrier
  • great dane
  • irish setter
  • miniature schnauzer

Types of hypothyroidism in dogs

Canine hypothyroidism can be primary or secondary. The primary is by far the most common. We explain it in more detail:

  • Primary hypothyroidism: basically it is due to lymphocytic thyroiditis, autoimmune or Hashimoto's, which is hereditary, or to a thyroid gland atrophy of idiopathic origin. In both disorders, thyroid tissue is destroyed. In fewer cases the cause is a neoplasm in the thyroid gland.
  • Secondary hypothyroidism: can be caused by trauma, tumors or malformations in the pituitary, iodine deficiency or excessive use of glucocorticoids.

We can also talk about congenital hypothyroidism, diagnosed in young dogs. The most typical symptom is dwarfism, in addition to dermatological problems, constipation or alterations in mobility..

Symptoms of hypothyroidism in dogs

Signs of Hypothyroidism in Dogs are varied and nonspecific, since the disease affects the whole organism. Therefore, the consequences of hypothyroidism in dogs can be many and it is important to go to the vet as soon as possible. We can classify the symptoms depending on the affected area, these being the most common:

General symptoms

As general and most common symptoms, we find:

  • Lethargy.
  • Cold intolerance.
  • Exercise intolerance.
  • Weight gain.
  • High cholesterol.
  • Constipation.
  • Anemia.
  • Immunosuppression.
  • General weakness.

Neurological symptoms

The neurological symptoms of hypothyroidism in dogs are usually more common in cases of secondary hypothyroidism. The signs that can alert us are:

  • Facial paralysis.
  • Head tilt.
  • Balance disorders.
  • Ataxia.
  • Leg weakness on the same side.
  • Limp.
  • Seizures.

Dermatological symptoms

Within the extensive list of symptoms of hypothyroidism in dogs we also find skin signs. In these cases, it is common to observe a bilateral and symmetrical hair loss from the front of the neck to the chest, the sides, the back of the thighs and the top of the tail. In addition, the hypothyroid dog may develop the following dermatological symptoms:

  • Dry, thickened, inflamed, and darkened skin.
  • Matte, dry and brittle hair.
  • Seborrhea.
  • Poor hair growth, which also falls out easily.
  • Pustules and irritations.
  • Accumulation of fluid on the face.

Cardiovascular symptoms

Among the cardiovascular signs we highlight:

  • Slow heart rate.
  • Abnormal heart rhythm.
  • Atherosclerosis.

Reproductive symptoms

A deficiency of the T4 hormone in dogs can also cause consequences in the reproductive system, such as these:

  • Infertility.
  • Absence of zeal.
  • Milk secretion outside of lactation.
  • Enlarged breasts in males.

Eye symptoms

Eye health can also be impaired when the function of the thyroid gland is impaired, causing the following problems:

  • Blepharitis.
  • Corneal ulcers.
  • Abnormal eye movements.
  • Corneal dystrophy.

Behavioral symptoms

Finally, and as in other pathologies, the dog with hypothyroidism may present certain signs that could be confused with behavior problems such as these:

  • Aggression, which can be context-independent, unpredictable, and intermittent.
  • Afraid.
  • Exaggerated shyness.
  • Compulsive behaviors.
  • Signs similar to cognitive dysfunction syndrome.
  • Hyperactivity.
  • Learning problems.

It should be noted that the presence of behavioral disturbances associated with canine hypothyroidism is still controversial. Aggression is the most frequently cited, but it is not known if is a symptom or hypothyroidism has aggravated an existing problem. Lastly, other symptoms of hypothyroidism are deafness or megaesophagus. In addition, it is associated with other diseases such as dilated cardiomyopathy, von Willebrand disease or myasthenia gravis.

Diagnosis of hypothyroidism in dogs

If your dog has some of these symptoms and you are wondering how to detect hypothyroidism in dogs, the truth is that there are several tests, which, of course, have to be requested and interpreted by the vet. Typically, this professional takes a blood sample and asks for the concentration of free T4 in the blood. If this thyroid hormone analysis yields normal values, the possibility of hypothyroidism is ruled out. But a low concentration does not imply hypothyroidism, so more tests are carried out, such as the one for stimulation elicited with TSH or the antithyroglobulin autoantibody assay. An ultrasound of the thyroid gland may also be done.

Treatment for hypothyroidism in dogs

The treatment for this disease is quite simple, but, in general, it must be given lifelong and it is necessary for the veterinarian to prescribe a follow-up and control to establish the appropriate dose. At first this will be calculated based on the weight of the dog. Treatment consists of pills for hypothyroidism in dogs. We see it in more detail:

Medications for hypothyroidism in dogs

As this disease is caused by a lack of hormones in the thyroid gland, treatment is based on providing the body with the hormones it lacks. In this way, the symptoms remit, although it will take several weeks or months to do so. Specifically, the dog is given once or twice a day levothyroxine sodium, which is a synthetic form of the hormone T4. Since levothyroxine comes in tablets, it is very easy to take with food. Remember the importance of adjusting the daily dose, only then will it be effective. Of course, only the vet can do it.

Image: perrogato.net

Diet for dogs with hypothyroidism

Hypothyroid dogs should be given a quality diet tailored to their vital circumstances and based on animal protein. In hypothyroidism in dogs, contrary to what happens in other pathologies, diet is not the basis of treatment, but it is can help alleviate some of the symptoms that occur in sick dogs.

Thus, for example, a diet restricted in fats and carbohydrates can help to regain the optimal weight to those horses that have increased it, a correct contribution of fiber prevents constipation or iron improves dogs with anemia. As there are so many symptoms that, in addition, can appear simultaneously, the ideal is that we follow the advice of the veterinarian to choose the food that can increase the well-being of our dog the most..

This article is merely informative, at AnimalWised.com we do not have the power to prescribe veterinary treatments or make any type of diagnosis. We invite you to take your pet to the vet in the event that it presents any type of condition or discomfort.

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