What Can Happen to a Dog with Hypothyroidism if It Is Not Treated?

A dog with hypothyroidism has insufficient thyroid hormone because his thyroid gland is failing or has been destroyed. The hormones secreted by your dog's thyroid gland control his body's metabolism or overall operating system. A thyroid hormone deficiency can affect any part of the body, from the skin to the nervous system. If hypothyroidism is not treated, a dog may either die from complications or suffer through life with mild to severe problems that often can easily be resolved.
  1. Causes

    • Thyroid disorders are often caused by an autoimmune disorder in which the dog's own immune system attacks the thyroid gland. Disorders of the thyroid also may be idiopathic, meaning the cause cannot be determined. Tumors are relatively rare causes of Thyroid problems. Hypothyroidism is genetically linked in some dog breeds. It is seen most often in middle-aged dogs. Spayed females seem particularly susceptible.

    Symptoms

    • Hypothyroidism can cause many and varied symptoms, some relatively minor and some life-threatening. Symptoms can be as subtle as general listlessness and mental dullness, or as frightening as a dog that suddenly can't walk. Other symptoms may include unexplained weight gain, chronic obesity, dull coat, bald spots, chronic ear infections, seizures and even droopy eyelids. Hypothyroidism can affect reproduction, causing irregular heat cycles, breeding problems in both males and females, and stillborn puppies.

    Diagnosis

    • Hypothyroidism is not always easy to diagnose. Blood tests evaluate the dog's thyroid hormone levels and the level of a thyroid-stimulating hormone produced by the pituitary gland. Other signs evaluated may include cholesterol levels and anemia. After the dog is diagnosed and stabilized on treatment, your veterinarian should test him at regular intervals to ensure the thyroid hormones are maintained at appropriate levels. Testing can be expensive. Tests ran $100 and up in early 2012, but costs can vary, depending on where you live and factors such as whether a technician or a veterinarian draws the blood and fees at the lab doing the testing and interpretation. You can shop around for the best local prices. Don't fail to check with the veterinary college if you live near one.

    Treatment

    • A dog with hypothyroidism will need to take a daily dose of synthetic thyroid hormone for the rest of his life. Your veterinarian will write a prescription, which may be filled at the veterinarian's office or by a mail-order prescription service. The most common supplement is levothyroxine, which is sold under several brand names. This is the same medication used for humans, but weight is an important factor in dosage, so the dog's dose is usually much smaller. Cost per pill ranges from eight to 23 cents in 2012, depending on dosage. The pills are small; you can easily put them down the dog's throat, conceal them in a soft treat such as a piece of hot dog or a glob of peanut butter, or mix them into his food.

    Prognosis

    • Once you start thyroid hormone replacement therapy, you probably will see substantial improvement in your dog's lethargy, dullness and walking problems within a week or two. Skin problems and other symptoms may take months to recede. Once your dog is stabilized on a maintenance dose, he should live a long and happy normal life without recurrence of symptoms, as long as you don't stop giving him his pills.

      Always consult an experienced veterinarian regarding the health and treatment of your pet and follow instructions carefully.