Hypothyroidism in dogs: symptoms and treatment
The most common hormonal or endocrine disorder seen in dogs today is hypothyroidism, otherwise known as an underactive thyroid gland. This condition is most commonly seen in middle-aged and older dogs, although some cases have been reported in younger animals as well. Some breeds seem to be genetically predisposed such as standard Poodles, Schnauzers, and Retrievers, but it’s also common in mixed breeds and other breeds of dogs as well.
While in many cases we don’t know the causes of an underactive thyroid gland and thyroid atrophy in dogs, in other cases there is an autoimmune destruction of the thyroid gland by the dog’s own immune system. In fact, toxic environmental exposure, nutritional factors, and even vaccinations have sometimes been incriminated as contributing to autoimmune destruction of a dog’s thyroid gland, known as autoimmune thyroiditis.
Symptoms of a low thyroid can vary tremendously. Some of the more common ones include weight gain/low energy without an increase in appetite, cold intolerance, chronic ear and/or skin infections along with coat changes including dull, dry or oily coats, hair loss often symmetrically along the back, as well as thin skin. Some pets may develop neurologic complications including behavioral changes and aggression, as well as problems with the facial nerves including a Bell’s palsy-like syndrome resulting in a facial droop.
Other pets may manifest with chronic regurgitation or vomiting problems, sometimes diagnosed as megaesophagus, where chronic regurgitation can become a frustrating and health threatening problem. And while one can see that there are many possible signs of a low thyroid in this common endocrine/hormonal disorder of dogs, hypothyroidism is also equally as overdiagnosed by many veterinarians. Chronic illness anywhere in the body, as well as many drugs such as Phenobarbital, can actually lower measured resting thyroid hormone levels such as T4, that can often erroneously lead veterinarians to misdiagnose this condition.
Other chronic illnesses and certain drugs can lower T4 levels dramatically often resulting in what is known as euthyroid sick syndrome, meaning that there is not a low thyroid condition, but other disorder or medication causing the low blood levels, often resulting in a misdiagnosis by a veterinarian. Therefore it’s important whenever trying to diagnose a pet with this disease, that a full blood thyroid panel be done, including measurement of blood T4, Free T4 by equilibrium dialysis, as well as TSH levels and thyroid and thyroglobulin autoantibodies, to most completely assess thyroid function in dogs. Treatment is very inexpensive using either synthetic L-thyroxine, or in those more holistically inclined through use of armour thyroid supplementation. This is also a disease where I feel nutritional factors play a role in causation as well as treatment.
Insuring an optimal natural diet such as Azmira, Pet Guard or Wysong, or even a proper home made diet, can help prevent as well as help in treating affected dogs. Nutritional supplements such as enzymes like Prozyme or NaturVet Enzymes & Probiotics added to meals, which increase trace mineral digestion and absorption such as iodine and selenium, can also help provide proper nourishment and support for the thyroid gland. Kelp powder and lecithin granules can also be important nutritional supplements to consider in affected dogs.