Ask the Vet | Graves Disease in Dogs

Graves disease in dogs is a condition that is caused by a hyperactive thyroid gland and will occur in dogs that have hyperthyroidism. The condition is considered autoimmune and the immune system will produce antibodies as a response to the thyroid hormones. The disease is rare in dogs, but can have complex manifestations. The treatment options may vary and will aim at reducing the activity of the immune system on one hand, and reducing the amount of thyroid hormones produced on the other.

Causes of graves disease

Graves disease is caused by an excess of thyroid hormones. The immune system is also involved in the disease, as it will react to this excess of hormones by producing certain antibodies. It is believed that immune system’s reaction is triggered by the presence of certain bacteria or viruses. The disease is believed to be hereditary.

Symptoms of Graves Disease

• The graves disease in canines can have various means of manifestation. You can notice the following symptoms:
• Enlarged thyroid gland, located at the base of the neck. This may also lead to a change in the voice of the dog, as the thyroid can press against the vocal chords
• Weight loss
• Increased appetite, thirst and urination
• Increased blood pressure
• Irregular heart beat
• Protruded eyes, due to the inflammation
• of the ocular muscles
• Episodes of hyperactivity and agitation,
• followed by extreme exhaustion
• Insomnia
• Tremors
• General state of weakness
• Breathing problems
• Hyperthermia and fever
• Hair thinning or even hair loss
• Chronic sinus infection
• Hypercalcemia
• Upset stomach with diarrhea and vomiting

The condition may affect each system in the body. The dog may present only certain symptoms and these may occur and disappear for certain periods of time.

Diagnosing Graves Disease in Dogs

The disease can be diagnosed judging by the symptoms displayed by the dog and by testing the level of thyroid hormones.

Graves Disease Treatment Options

The management of Graves disease in dogs will focus on 2 aspects:

• Inhibiting the immune system
• Reducing the amount of thyroid
• hormones secreted by the dog

However, there is no known treatment for this condition. Different treatments may be tested and the dog should be monitored to see if the treatment works.

The immune system’s activity may be controlled with corticosteroids such as Prednisone, which will suppress the secretion of any antibodies. However, the treatment will also make the dog more vulnerable to diseases, as the immune system plays an important part in the defence mechanism of the dog’s body.

The thyroid hormones may be controlled by administering medication such as carbimazole, which will reduce the activity of the thyroid gland. The vet may also recommend surgically removing 1 lobe of the thyroid gland or only parts of the gland. Radioiodine therapy is also a treatment option and may give permanent results. By Dr Ruan Du Toit Bester

Hope this info helps

Till next week 

Dr Ruan

Ask the Vet: Royal Veterinary Centre

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