Like in humans, thyroid glands are an important part of a dog’s anatomy and they affect a number of different organs in a dog’s body. If a dog’s thyroid gland is not working properly, this can cause problems with the heart, liver, kidneys, brain and skin.
While the importance of these glands is undeniable, pet owners rarely know where they are located or what they look like. More importantly, many are often unfamiliar with common thyroid problems in dogs and what to do about them. Let’s take a look at dogs' thyroid glands, their role and some common related issues that may affect your pooch.
What's a Thyroid Gland in a Dog?
Dogs have two thyroid glands which are located on each side of the windpipe at the base of the neck. These glands produce thyroxin, a hormone that accelerates a dog’s metabolic processes and affects other organs in the body. Thyroxin generally stimulates every tissue in the canine body to produce proteins, increases the amount of oxygen that cells use and regulates calcium balance.
Thyroid problems are one of the well-known ailments that affect dogs. Hypothyroidism is the most common thyroid problem that veterinarians have to deal with, but there are also hyperthyroidism and thyroid tumors.
1. Hypothyroidism in Dogs
Hypothyroidism is a condition when thyroid glands doesn’t produce enough hormones to keep the dog’s metabolism in balance.
What causes hypothyroidism:
This ailment is most often a result of aging in dogs. However, it can also be caused by a malfunction in the dog’s immune system where it's attacking a thyroid gland, or a shrinking thyroid. In some cases, thyroid tumors (discussed below) can cause hypothyroidism as well.
Some breeds are more prone to this illness than others, especially large and medium sized dogs, including Retrievers, Boxers, Greyhounds, Bulldogs and Great Danes. The list also includes certain smaller breeds like Miniature Schnauzers and Poodles.
Signs and symptoms of hypothyroidism:
Weight gain is one of the typical symptoms of hypothyroidism. Since this ailment slows down a dog’s metabolism, weight gain happens more easily. Dry, sensitive skin is another sign, along with skin sores that may appear. In addition to skin problems, dogs often start shedding and lose hair. A dog’s coat can become dull, flaky and scurfy.
Other symptoms include lethargy, weakness, decreased heart rate, sensitivity to cold, constipation, and in many cases secondary infections, most notably in the dog's ears and/or eyes. Hypothyroidism can also negatively affect a dog’s mental alertness and cognition, and his ability to learn new things.
How to treat hypothyroidism:
In general, hypothyroidism in dogs cannot be cured but only managed. In most cases, the treatment is expected to last throughout the dog's entire life, and only in very rare cases can an animal have a complete recovery.
Therapy includes administration of thyroid hormone in a synthetic form. Dosage will be prescribed by your vet and it may change over time, so regular checkups are necessary. Fortunately, with this therapy, dogs are able to lead normal and active life.
2. Hyperthyroidism in Dogs
Contrary to hypothyroidism, hyperthyroidism is a disease which causes thyroid gland to to the opposite and produce excessive amounts of thyroxin. The overproduction of this hormone pushes the dog's body into overdrive, which leads to increased metabolism.
What causes hyperthyroidism:
While hypothyroidism is a common ailment in canines, hyperthyroidism is very rare and in most cases is caused by tumor of the thyroid gland or the over-functioning thyroid glands. Another cause of hyperthyroidism may be overreaction to medication for treating hypothyroidism.
Signs and symptoms of hyperthyroidism:
Symptoms of this ailment are completely opposite of those of hypothyroidism and include weight loss, often in combination with increased appetite, vomiting, diarrhea, rapid breathing and rapid heart rate. Hyperactivity is a common sign of hyperthyroidism as well. In many cases, enlarged thyroid gland can be felt as a neck lump.
Some dogs with this disease can exhibit atypical symptoms like apathy, poor appetite, weakness and depression.
How to treat hyperthyroidism:
Treatment for hyperthyroidism in dogs will depend on the cause and severity of the condition. In those cases where medications for hypothyroidism caused the disease, a simple dosage adjustment can be enough for hyperthyroidism symptoms to subside.
Another common therapy involves drugs that inhibit the production of thyroid hormones but this can’t always be administered. Surgery to remove a thyroid gland may be recommended in cases where only one thyroid gland is affected.
Hyperthyroidism caused by a tumor of a thyroid gland gets treated by dealing with tumor itself, as discussed below.
3. Thyroid Tumors in Dogs
Thyroid tumors in dogs are not a common occurrence but when tumors in thyroid glands do occur, statistically they are almost always malignant.
What causes thyroid tumors:
It is still unknown what the cause of thyroid tumors in dogs are. However, we know that older dogs are more susceptible to them. Also, some breeds are at higher risk of developing thyroid tumors, especially Beagles, Boxers and Retrievers.
Signs and symptoms of thyroid tumors:
The symptoms of thyroid tumors are basically the same as those characteristic for hyperthyroidism. However, these symptoms may or may not be present, which depends on the type of tumor and whether it causes the thyroid gland to produce excessive amounts of thyroid hormone.
One important clinical sign of a thyroid tumor in a dog is a noticeable mass on his neck, which usually causes changes in pet's breathing sounds, as well as his barking.
How to treat thyroid tumors:
As with any other tumor and type of cancer, treatment options range from radiation, chemotherapy and surgery. Depending on the size and spread of the tumor, your vet will decide on the best treatment option for your pooch.