Thyroid problems in dogs are not uncommon in middle-aged to older canines. Your dog’s thyroid gland (much like your thyroid gland), is located in the neck region near the Adam’s apple, and is an important member of his body’s endocrine system.
The thyroid gland produces certain multitasking hormones that play a major role in your pet’s metabolism, and affect the function of many parts of his body. If these hormones are not produced at optimal levels, major problems can occur in your dog’s health.
What Causes Thyroid Problems in Dogs?
The two most common thyroid conditions in pets are Hyper-thyroidism and Hypo-thyroidism.
Hyperthyroidism is when the thyroid gland is overactive and produces too much of a good thing. This disorder is much more common in cats than dogs. It is caused by an increased production of thyroid hormones due to an enlarged thyroid gland and results in an elevated metabolism. It is more common in middle-aged to older cats but can be successfully treated if caught fairly early and diagnosed by a veterinarian.
Hyperthyroidism in dogs is considered rare. If it does occur, the symptoms most likely to be noticed would be the dog losing weight despite a healthy appetite and regular nutritious meals. The pet owner might also discover a lump in the animal’s neck in the area of the thyroid gland. This disease is so uncommon in dogs that it’s usually found to be the result of a thyroid tumor.
Hypothyroidism is considered a much more common disease in dogs and as you may have guessed, it is characterized by an under active thyroid gland. Your dog’s thyroid gland produces a number of hormones but the two main ones are T3 (triodothyrine) and T4 (thyroxine).
T3 and T4 regulate body temperature, heart rate, and metabolic rate. Since the thyroid gland in this case is under active, not enough of these hormones are produced and this results in an abnormally slow metabolism.
Hypothyroidism in dogs is usually caused by one of two things:
- The first is termed lymphocytic thyroiditis and is the most common cause. It is thought to be an autoimmune disorder, wherein the body’s immune system mistakenly attacks the healthy cells of the thyroid gland. No one is sure exactly why this happens but we do know that genetics plays a part in this condition because it’s a hereditary trait.
- The second cause is called idiopathic thyroid gland atrophy. “Idiopathic” simply means ’cause unknown’. “Atrophy” means ‘a wasting away of body tissue’. What we do know for sure about idiopathic thyroid gland atrophy, is that normal thyroid tissue is replaced by fatty tissue.
These two main causes of hypothyroidism in dogs account for approximately 95% of cases. The other 5% can be attributed to rare diseases or tumors ~ either of the thyroid gland or the pituitary gland.
The pituitary gland is the main endocrine gland. It’s a small gland located at the base of your dog’s brain. Size notwithstanding, it produces a number of different hormones that regulate other endocrine glands in your canine’s body, including the thyroid gland. The hormone it secretes to target the thyroid is called TSH ~ Thyroid Stimulating Hormone.
What are the Symptoms of Hypothyroidism in Dogs?
Usually the effects of a dog’s shrinking or inflamed thyroid gland come about very slowly. Consequently, the symptoms happen gradually and can be easy to miss at first. They include:
- Lethargy ~ You notice your dog has a lack of energy or enthusiasm. He sleeps more than usual and tires out more easily.
- Weight Gain ~ His appetite hasn’t changed and you haven’t increased his treats, but his weight is creeping up.
- Dry, Dull Haircoat ~ His once lustrous coat is dry and brittle with excessive shedding. The skin underneath is scaly.
- Low Tolerance for Cold ~ You notice him shivering in warm temperatures and seeking out warmer places to lay down.
- Loss of Fur ~ His tail is almost bald and he’s losing fur around the collar area, although his skin isn’t red and inflamed.
- Inactivity ~ He used to dance with joy when you brought out the leash, now he just doesn’t seem interested.
- Skin Darkening and Thickening ~ You can see a darkened pigment on his skin which is thickening to the point of skin folds.
- Ear Infections ~ He’s more prone to ear infections and his ears have a distinct odor.
- Mental Dullness ~ He used to be sharp as a tack and quick to follow a command or perform a trick. Now his mental acuity seems decreased.
If you think your dog may have hypothyroidism or are at least concerned about the symptoms he’s presenting, a trip to your veterinarian is the next step. If the good doctor suspects a thyroid problem, he or she will do a series of blood tests for a definitive diagnosis.
And Now for the Good News…
Canine hypothyroidism is not a life threatening disease; Although if left untreated, it will most certainly detract from a dog’s quality of life. But the good news is, since most thyroid problems in dogs are associated with low T3 and T4 levels, treatment is a simple matter of Hormone Replacement Therapy.
If your dog were to be diagnosed with hypothyroidism, he would need to take an oral drug daily for the rest of his life, since the disease can be treated but not cured. But the treatment is fairly easy, very effective, and quite affordable. With hormone supplementation, a dog’s response to the therapy is relatively quick and dramatic. Activity levels begin to improve within a few weeks although skin conditions and ear infections may take a few months to clear up completely.
The drug of choice for canine hypothyroidism is levothyroxine, given to the dog either once or twice a day. The medication is begun at a low dose according to the animal’s weight and is adjusted periodically until the proper blood level is achieved. Levothyroxine is an FDA approved drug designed to take over the function of the thyroid hormones that the thyroid gland is no longer able to produce.
Is Your Dog at Risk for Developing Hypothyroidism?
As mentioned earlier, hypothyroidism is most common in middle-aged to senior dogs. It is also found to be most frequently diagnosed in medium to large breeds.
Although this thyroid condition can affect any canine breed, there is a higher incidence in Cocker Spaniels, Doberman Pinschers, Golden Retrievers, and Irish Setters.
Now that you are aware of thyroid problems in dogs, which pets are most likely to be affected, and what the signs are, you can be better informed and equipped to deal with the condition should it arise in your dog. Remember, the symptoms of an affected thyroid gland will typically manifest very slowly. If you think your dog is showing signs, there’s no need to rush him to the emergency clinic; But do make an appointment with your veterinarian to bring your pet in for an examination and consultation.
Thank you for reading my article on Thyroid Problems in Dogs. Be sure to leave me any questions or comments you have or any experiences you would like to share in the section below.