Hypothyroidism Jan 17, 2009 23:15:23 GMT -5
Post by charmingnancy on Jan 17, 2009 23:15:23 GMT -5
What is Hypothyroidism?
Hypothyroidism is a disorder in which the thyroid gland (two small lobes located in the neck ) secretes insufficient thyroid hormone. Hypothyroidism isn’t life threatening, but it does diminish quality of life. Once diagnosed, however, the disorder is relatively easy to treat.
What is the function of the thyroid?
The thyroid gland produces the thyroid hormones that are critical to maintaining your dog’s normal metabolic rate. This is the speed at which the body converts nutrient energy into energy fueling the body. If the thyroid gland degenerates or becomes inflamed, it can no longer produce sufficient quantities of hormones. As a result, cells don’t convert the nutritional energy it needs into biologically usable fuel as fast as usual.
What breeds are prone to it?
Hypothyroidism is the most common endocrine (hormonal) disorder in dogs and often develops between the ages of 4 to 10 years. It usually affects castrated male and spayed female dogs. A variety of dog breeds are afflicted with this condition, such as the golden retriever, Doberman pinscher, greyhound, Irish setter, dachshund, miniature schnauzer, Great Dane, poodle, and boxer.
The disease also occurs in mix breed dogs and many other breeds.
What are the symptoms?
This decreased cell function causes a number of physical changes in a hypothyroid dog. Nearly half of such dogs gain weight (with no change in diet). Over a third become lethargic and mentally dull, and just under a third show hair or skin abnormalities. Hair-producing cells slow down, so there is less hair growth and more hair loss. Skin-producing cells slow down, so there is more wrinkling and seborrhea (dandruff) . Also, hypothyroid pets may suffer an increased propensity to joint disease, especially ligament damage. Since the physical signs of hypothyroidism develop gradually and vary from dog to dog, the disorder often goes undiagnosed.
How is it diagnosed?
Diagnosing hypothyroidism would seem to be as simple as measuring thyroid-hormone levels in the blood. However, this simple technique can give an inaccurate diagnosis because some illness such as Cushing's disease- overactive adrenal glands-- and medications, such as cortisone suppress the level of circulating thyroid hormones. The most accurate test is the - thyroid stimulating hormone -TSH- response test. In this test, the veterinarian measures thyroid-hormone levels in the dog’s blood, administers TSH (a chemical that stimulates thyroid-hormone secretion), then remeasures hormone levels to determine whether the thyroid gland responded by producing additional thyroid hormones. While the TSH response test is reasonably accurate, it is expensive to administer. Also, this hormone is now difficult to find because of decreased production by the manufacturers.
How is it treated?
Veterinarians treat hypothyroidism by prescribing supplemental thyroid hormone, which the owner must administer to the dog orally once or twice a day. These medications are initially prescribed according to your pet’s weight. Your veterinarian will closely monitor your dog in the initial stage of treatment by retesting the thyroid level- T4- to make sure the animal is getting the appropriate dosage. Too little hormone won’t alleviate the signs, while too much can cause a dog to develop hyperthyroidism (excessive thyroid hormone causing agitated and overactive behavior, weight loss, excessive drinking, and excessive urination). Once thyroid- hormone levels have stabilized within a normal range, your veterinarian will likely check the levels every six months to every year. The dose levels of medication used to treat this disease in dogs is much higher than the rate use to treat hypothyroidism in people.
What is the prognosis?
Once treatment begins, most hypothyroid dogs are increasingly active and show fewer behavior problems within a week. Hair growth typically accelerates in about a week, too, although bare spots may take months to fully grow in. Most dogs begin to lose excess weight within 2 to 4 weeks of starting treatment.