Pets Adviser explains that the symptoms of thyroid problems in dogs vary by the specific type of condition affecting the gland. For instance, thyroid tumors cause symptoms such as coughing and decreased appetite. In comparison, hyperthyroidism, a condition in which malfunctioning thyroids produce excess hormones, causes increased appetite, weight loss and restlessness.
The thyroid gland is located just under the larynx in the dog's trachea, according to the Dog Owner's Guide. The gland's operations are controlled by the pituitary gland, according to PetMD. Thyroids produce hormones that increase canine metabolism. If a malfunction causes the gland to produce excess hormones, the result is hyperthyroidism. The condition leads to frequent urination, an increased heart rate, a dull coat, labored breathing, diarrhea, vomiting and an enlarged thyroid.
While hyperthyroidism is rare, according to PetMD, its counterpart, hypothyroidism, is far more common. This condition is a result of the thyroid producing fewer hormones than the body requires. Signs of hypothyroidism include lethargy, hair loss, weight gain, lowered heart rate and general weakness. According to Pets Adviser, the symptoms appear at different points in time.
Depending on the cause, thyroid problems are managed with medication, radiotherapy, chemotherapy and surgery. Because the symptoms of thyroid problems can be confused with those of other canine diseases, Pets Adviser encourages dog owners to consult with a veterinarian if they notice something unusual about their animals.