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Hypothyroidism in Dogs: Causes, Symptoms, Treatment and Support

Hypothyroidism in Dogs: Causes, Symptoms, Treatment and Support

What is Hypothyroidism in Dogs?

Hypothyroidism in dogs refers to an underactive thyroid gland in your pet. This means that the gland, located in the neck near the trachea, has compromised functions and it is not producing enough thyroid hormone resulting in a decrease in the metabolic rate.

What Causes the Hypothyroidism in Dogs?

One of two diseases can cause hypothyroidism in dogs:

  • Idiopathic Thyroid Gland Atrophy: it is not studied enough and is poorly understood. This condition occurs when fat tissue replaces the normal thyroid tissue.
  • Lymphocytic Thyroiditis: it is the most common cause of hypothyroidism and is thought to be an immune-mediated disease. It happens when the immune system starts to think that the thyroid is abnormal or foreign to the body and it attacks it. Like the first condition, it is not fully understood, but in this case, it is thought that genetics play an important role in its occurrence.

Other causes like rare diseases and cancer can also be related to hypothyroidism, but occur in very few cases.

What are the Symptoms of Hypothyroidism in Dogs?

This condition causes the metabolic rate to slow down, affecting a majority of the organs in the body. Most dogs develop symptoms like:

  • Weight gain
  • Lethargy
  • Intolerance to cold
  • Excessive shedding (with dry and dull hair)
  • Dark pigmentation of the skin
  • High occurrence of skin and ear infections
  • High blood cholesterol
  • Slow heart rate

Other dogs will develop even more severe symptoms like:

  • Fat deposits in the corneas of the eyes
  • Keratoconjunctivitis (dry eye) due to lack of tear production
  • Infertility problems. Intact females can also have a lack of heat and a higher chance of miscarriages, and intact males can lose libido.
  • Abnormal function of nerves (causing lameness, lack of coordination, and head tilt) and thickening of the facial skin (causing the dog to have a “tragic facial expression”) are some of the other more severe symptoms.

Hypothyroidism in Dogs: Causes, Symptoms, Treatment and Support

What are the Diagnostic Tests?

Hypothyroidism can be diagnosed with a blood exam called Total Thyroxine (TT4), which measures the blood level of one of the thyroid hormones. Some veterinarians can conduct this in-house, while others may need to send it to an external lab for testing. More often than not, based on the blood results and clinical signs, a diagnosis is reached. If necessary, the veterinarian can request extra exams like the Free T4 by equilibrium dialysis (FT4 by ED) and/or a T3 Suppression test. If a definitive diagnosis is not reached with the aforementioned blood tests, a thyroid scan (thyroid scintigraphy) may also be performed, or a recheck of the TT4 after a few weeks may be conducted.

What are the Treatment Options for Hypothyroidism in Dogs)?

Your local vet is best equipped to treat your dog based on the clinical signs and the diagnostic results. Hypothyroidism is treatable, but there is no cure, and usually requires a lifelong prescribed, oral medication. The best way to take care of a dog with hypothyroidism is by talking to your vet and following their treatment plan so as to keep your dog comfortable, healthy, and have the condition under control.

Also, at NHV, our pet experts and in-house veterinarians can help you with questions and guidance on how to take care of them naturally.

Hypothyroidism in Dogs: Causes, Symptoms, Treatment and Support