This condition is seen in dogs and many times looks like a behavioral or aging problem. Hypothyroidism occurs because of inflammation of the thyroid gland that causes it to produce inadequate amounts of the thyroid hormones, just like it does in humans. If we treat this disease early in the dogís life, it is possible to prevent the lifetime use of thyroid supplements. Cats, on the other hand, have the opposite problem ó called hyperthyroidism.Here are the main symptoms: You might notice your dog gaining weight or losing the normal amount of energy. You may also see hair loss or a dull hair coat, the tendency to act cold; or they might get more infections than usual. More rarely, they can have an erratic or unstable temperament and show irritability or aggression!Medically, many of these dogs display elevated fasting cholesterol and triglycerides, mild anemia and elevated liver values prior to thyroid levels decreasing. Neurological weakness, corneal deposits, heart arrhythmia and appetite changes can also occur later in the disease. A decrease in function of this gland can also be due to age, medications such as corticosteroids, lack of exercise or exposure to toxins.Due to the general nature of the symptoms, this disease is not always easy for us to recognize. Its symptoms, such as weight gain, poor skin and hair coat, increased thirst and urination and progressive lethargy often occur gradually; and can be easily missed or mistaken for many other ailments.It is seen in some purebred dogs more than others. The Doberman pinscher, Golden retriever, Irish setter, Great Dane, boxer, cocker spaniel, dachshund, poodle and miniature schnauzer are all prone to hypothyroidism. Regular blood tests, including a thyroid panel as part of your dog’s annual wellness exams, can help with the diagnosis; even then, the results can be misleading and may not reveal the initial stages of the disease.The cause is usually inflammation of the thyroid gland ó a small, butterfly shaped gland in the neck. This inflammation causes the gland to be underactive or unable to produce adequate amounts of the important thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid hormones play an important role in metabolism, which is why hypothyroidism can cause such a wide range of debilitating symptoms.While hypothyroidism affects dogs of all ages, the average age of onset is 7 years old, with most dogs developing the condition between the ages of 4 and 10 years.Besides the blood lipid issue mentioned before, we also see a mild anemia and elevated liver values. Some dogs will show an overall weakness, and your veterinarian may notice some deposits in the eyes, a heart dysrhythmia (an odd beat pattern) or a poor appetite even though they gain weight.A lack of energy is often the first sign noticed. It is typically evidenced by frequent napping, exercise intolerance or loss of interest in running and playing. You might notice they canít endure the cold like they used to and many of these dogs lay down near the heater vents. They are also prone to chronic infections of the skin or ears, and have a dull, dry, brittle, thin or greasy hair coat and even hair loss or failure to regrow clipped hair. These dogs often have a slow heart rate. By the time obvious symptoms occur, a significant portion of the thyroid gland, about 70%, may already be damaged.Remember, senior dogs should have a senior blood panel about once a year. In this panel will be a check of these thyroid hormones, and it is in this lab test where we will find a drop in the thyroid hormones. This test looks specifically for T3 and T4 levels, but also anti-thyroid antibodies, which is likely an immune-mediated thyroiditis that can also be the culprit.What can you do? It is easy to miss these subtle signs of hypothyroidism until finally a test result might show your dog to be positive for this issue. If caught early, some veterinarians recommend feeding an unprocessed, fresh food diet (not raw or bones) and then possibly doing blood titers, instead of vaccines, as some believe these can unduly stress your dogís immune system. Frankly, anything that can decrease stress on the dogís liver is a good thing. This could allow you to delay or prevent lifelong thyroid medications. If not caught early, treatment involves giving supplements for the rest of your dogís life. These supplements usually work quickly and are not hard to give.Because hypothyroidism is so difficult to recognize and diagnose, all veterinarians strongly recommend the yearly senior lab tests for dogs over 6 to 7 years of age.Yet another reason to work with your petís doctor, and this is especially true when your buddy begins his senior years.
Dr. Jim Humphries is a veterinarian and the medical director for a national hospice and end-of-life practice. He also serves as a visiting professor at the College of Veterinary Medicine at Texas A&M University. He lives in Falcon with his wife, horses, and Great Danes. https://www.HomeWithDignity.com
