Since your dog’s thyroid glands regulate her metabolism, an underactive thyroid generally means her metabolism is slower than it should be.
With proper care, your hypothyroid dog can have a normal life span and good health.
According to Mary Shomon, About.com’s thyroid expert:
“While there is a genetic predisposition for thyroid disorders, environmental factors such as pollutants and allergies probably play a role as well.”
Your dog’s thyroid gland is a small butterfly-shaped organ in his neck, with one lobe on each side of his trachea.
There are two ways your pup can end up with hypothyroidism. In its pure form hypothyroidism is usually an immune system disorder also known as autoimmune thyroiditis, it means his body is attacking the tissues of his thyroid gland.
In response to this attack, the thyroid will first try to compensate by producing greater and greater amounts of the thyroid hormone thyroxine. But after awhile, the gland becomes depleted. It’s at this point your dog develops symptoms of the disorder and is diagnosed with hypothyroidism.
The other way your dog can end up hypothyroid is her body simply produces less thyroid hormone over time, and eventually she does not produce enough for normal biological processes.
Thyroxine is an extremely important hormone in your dog’s body. It plays a significant role in bodily functions such as food metabolism, growth and development, oxygen consumption, reproduction and resistance to infection.
Symptoms of Hypothyroidism
If your dog has hypothyroidism, she’ll have at least some and often several of the following symptoms:
- Depression; also significant behavioral changes like aggression, head tilting, anxiety, compulsiveness, seizures
- Lack of energy – frequent napping, exercise intolerance, lack of interest in physical activity and play
- Weight gain without an increase in appetite
- Low tolerance for the cold; slow heart rate
- Skin changes – dryness, hair loss, discoloration or thickening, bacterial infections
- Chronic infections, including ears, skin
Will My Dog Develop This Condition?
The disorder is relatively rare in miniature and toy breeds, and is more common in medium to large size dogs.
Male and female dogs acquire hypothyroidism at about the same rate, but spayed females are more prone to the disorder than unspayed females.
Several breeds are genetically predisposed to the disorder, including:
- Airedale terriers
- Cocker spaniels
- Doberman pinschers
- Golden and Labrador retrievers
- Irish setters
Other potential causes of hypothyroidism include:
- Some medications, in particular corticosteroids, can bring on hypothyroidism
- Lack of exercise can also play a role in reducing the production of thyroid hormone
- If your dog is exposed to a lot of toxins, including vaccinations, it can increase her risk of developing hypothyroidism
Most dogs develop hypothyroidism between the ages of 4 and 10.
Diagnosis and Treatment
There are a number of ways to measure the thyroid health of your pup through blood tests with ‘T’ names like free T3, free T4, T3, T4, AAT3, AAT4 and TSH.
If your dog is diagnosed with autoimmune thyroiditis -- confirmed by elevated AAT3 and AAT4 levels -- unfortunately, in most cases you’ll need to start your pet on a synthetic thyroid pill and she’ll be on it for the rest of her life.
Usually by the time your pet has enough auto-antibodies to be measured on a blood test there has been irreparable thyroid damage and synthetic hormone replacement is almost always inevitable.
However, if there’s no autoimmune disorder present, my recommendation is to try stimulating remaining thyroid tissue to begin working again. If your dog’s thyroid glands have taken early retirement -- confirmed by low thyroid levels on blood work -- it’s possible the thyroid can be regenerated using a more natural form of thyroid replacement.
For years I sent my patients’ thyroid panels to Michigan State University for analysis. However, in 2001, after learning about Dr. Jean Dodds’ extensive databank of breed reference ranges, I began using Hemopet to analyze my thyroid panels.
Dr. Dodds believes a neutered year-old Yorkie will have different baseline results than an intact 11-year-old female Lab that’s had three litters. Dr. Dodds performs the same tests as MSU, but then compares the results to other dogs of the same breed, sex and age.
Prevention, Not Treatment, is the Goal
In my practice, I address every blood value that is out of range on all of my patients. Rarely is an out-of-range value ‘good enough’ or ‘healthy enough’ as far as I’m concerned. This is where clinical pathology -- charting internal organ changes on blood work over time -- becomes very important.
If I can see that a patient’s thyroid levels are dropping steadily from mid range, to suboptimal, to borderline low, I will institute appropriate gland support before the gland completely fails.
This is what I call practicing veterinary medicine in the ‘gray zone’ -- the zone between white (where your pet’s health is near perfect) and black (the zone in which disease takes control).
In the gray zone, your pet’s condition is moving either toward health or away from it. When I see movement in the gray zone toward ill health, it’s the perfect time to take action.
This is the difference between proactive and reactive medicine. Most vets will wait not only for test results to show very low values, but also for their patients to exhibit three of the six classic symptoms of hypothyroidism before instituting synthetic hormone replacement. In other words, they wait for an animal to develop full-blown disease before they implement treatment.
In my practice, we are able to prevent many pets from having to be on lifelong thyroid medications by catching the gland’s under-activity very early in the game.
My advice is to find a holistic veterinarian who also sees opportunity in the ‘gray zone.’ He or she will be open to monitoring all your pet’s blood values, sending thyroid panels out for analysis (my recommendation is Hemopet), and can also prescribe thyroid glandulars and the cofactors (tyrosine and iodine) in the right dosages for your dog.
Beware This Hypothyroidism Imposter!
I highly recommend you also ask your holistic vet to look for underlying adrenal stress.
An adrenal disorder is very often the root cause of hypothyroidism. In such cases, the thyroid problem is actually just a symptom of the underlying adrenal issue. Your vet can submit a baseline adrenal profile for your dog to the University of Tennessee’s Endocrinology Lab.
In spayed and neutered dogs, in particular, removal of the gonads means a dramatic decrease in sex hormones. To make up for this loss, the adrenal glands are required to put in a lot of overtime. After years of too much work, the adrenals get stressed and exhausted.
Sick adrenal glands almost invariably lead to sick thyroid glands.
I identified this trend at my Natural Pet hospital in 2008 and since then, adrenal disease with symptoms of hypothyroidism has been the number one endocrine disorder diagnosed in my practice.
For a thorough discussion of the most common adrenal disorder, view my series on Cushing’s disease.
If it turns out your dog has an adrenal issue with an underactive thyroid as a secondary condition, your holistic vet will be able to guide you in the best way to support your pup’s adrenal glands toward renewed health and improved functioning. Often, good results can be achieved through a combination of homeopathic remedies, herbs, supplements, proper nutrition and regular exercise.
Just as your dog’s thyroid function very likely decreased in response to an adrenal gland disorder, many thyroid problems improve or resolve when the underlying adrenal dysfunction is addressed.