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your thyroid What you should know about hyperthyroidism and the most common cause, Graves’ disease function If you have a thyroid problem, it doesn’t necessarily mean that you will miss out on a happy and healthy life. This pamphlet explains the conditions that lead to the disease known as hyperthyroidism. As with any healthcare issue, you should talk to your doctor about your particular situation. What is the thyroid, and why is it important? The thyroid is an endocrine gland that plays a key role in regulating growth, development, and normal function of the body.1 It is a butterfly-shaped gland located in the front of your neck. The thyroid can affect your heart rate, your emotional state, your feelings of tiredness and hunger, and the condition of your skin and hair. In fact, your thyroid influences most cells in your body. Your thyroid controls your body’s functions by making several hormones, including thyroxine (T4), which is converted to triiodothyronine (T3).1 If you do not get enough iodine in your diet, your thyroid cannot produce enough T3 and T4. The amounts of T3 and T4 released into the bloodstream: • Regulate the body’s ability to turn food into energy • Affect rates of tissue growth • Affect the function of organ systems throughout the body The amount of thyroid hormones released by the thyroid gland is monitored and controlled by the pituitary gland which releases thyroid-stimulating hormone (TSH) when the thyroid hormone levels are too low.1 When your thyroid is functioning normally, TSH levels are relatively low. Thyroid disease With thyroid disease, thyroid hormones are over-produced or under-produced. Diseases of the thyroid gland include1,2: • Hashimoto’s disease – An autoimmune disease that causes the thyroid to produce too little thyroid hormone, causing hypothyroidism • Goiter – Enlargement of the thyroid gland • Thyroid nodules – Growth of thyroid tissue causing circular or oval-shaped lumps in the thyroid gland • Thyroid cancer – Growth of the thyroid gland, either goiter or thyroid nodules, that becomes cancerous Abnormal thyroid function can cause discomfort and symptoms such as tiredness, irritability, weight loss or gain, and inability to sleep. Hyperthyroidism Hyperthyroidism results from an overactive thyroid gland. With too much thyroid hormone in the bloodstream, the body “speeds up,” and may experience rapid heartbeat, mood swings, weight loss, or shaky hands. Since these symptoms are general, they may be mistaken for other conditions. The symptoms of hyperthyroidism and the severity may vary from patient to patient. A patient may or may not experience signs and symptoms. Signs and symptoms of hyperthyroidism are2: • Nervousness • Mental disturbances • Sleep disturbances • Vision disturbances • Thyroid enlargement • Rapid heartbeat • Weight loss • Shortness of breath • Heat intolerance • Tremor • Sudden paralysis • Alterations in appetite • Frequent bowel movements • Menstrual disturbance • Impaired fertility • Leg swelling • Fatigue and muscle weakness • Hyperthyroidism – Too much thyroid hormone is produced • Graves’ disease – An autoimmune disease that causes the thyroid to produce too much thyroid hormone, causing hyperthyroidism Thyroid gland • Hypothyroidism – Not enough thyroid hormone is produced Trachea (Windpipe) 1 What you should know about hyperthyroidism and the most common cause, Graves’ disease thyroid function and hyperthyroidism How do I know if I have hyperthyroidism? Thyroiditis. Thyroiditis is an inflammation of the thyroid tissue that may be caused by bacteria or a virus.8 This causes the thyroid gland to temporarily leak extra hormone into your bloodstream. For some people, hyperthyroidism caused by thyroiditis may be a recurring problem. If you have a family history of thyroid disease or if you report certain symptoms to your doctor, he or she can use several simple laboratory tests to check whether your thyroid gland is functioning normally. Your doctor may order a TSH test, which is the recommended test for evaluating thyroid hormone levels. It measures the level of thyroid-stimulating hormone (TSH), a hormone that controls the amount of thyroid hormone (T4 ) produced.3 Another test that may be used measures the amount of thyroxine (T4 ), circulating in your blood. Of these, the TSH test is recognized to be the most sensitive test for detecting too much or too little thyroid hormone. Postpartum hyperthyroidism. Women can develop hyperthyroidism after delivery of their babies when the thyroid becomes inflamed. The hyperthyroidism may evolve into hypothyroidism. Drug-related hyperthyroidism. Certain medications may cause the thyroid to function abnormally, causing hyperthyroidism. Patients should talk to their doctor if they experience any signs and symptoms. Over-treatment with thyroid hormone replacement. Taking too much thyroid hormone replacement may lead to symptoms of hyperthyroidism. • Mild hyperthyroidism – TSH levels fall below the normal range and T4 levels are normal. Signs and symptoms may or may not occur • Overt hyperthyroidism – Your thyroid makes too much thyroid hormone. T4 levels rise above the normal range while TSH levels fall below.4 Signs and symptoms are likely to occur What conditions lead to hyperthyroidism?5 Graves’ disease. The most common cause of hyperthyroidism is an autoimmune disease. Instead of responding to and removing substances which the body recognizes as foreign invaders, such as bacteria or viruses, the body’s immune system attacks its own tissue. The immune system produces antibodies that attach to the cells of the thyroid gland, which in turn stimulates excessive production of thyroid hormones. The tendency to develop the disease may be inherited. Some experts believe Graves’ can result from stress,6 though that does not appear to be the case for everyone with the disease. Many people with Graves’ disease also have eye problems. Swelling of the tissue behind the eyes pushes them forward, resulting in eyes that are red, inflamed, and appear to bulge.7 Thyroid nodules. Nodules are growths on the thyroid gland. They may increase in size and will often appear as a lump in your neck known as a goiter. The nodules may cause your thyroid to increase production of thyroid hormone, which causes the body’s functions to speed up. How is hyperthyroidism treated?5 The treatment for hyperthyroidism varies between patients. If you have hyperthyroidism, your age, severity of disease, overall state of health, and other factors all play a role in what your doctor chooses for you. One or more of the following treatments may be used: ntithyroid drugs. These drugs block the ability of the A thyroid to produce thyroid hormone. They do not damage the thyroid gland and may be used for short- or long-term treatment.9 Antithyroid drugs are also used to prepare a patient for treatment with radioactive iodine or for surgery. Radioactive iodine. This treatment, usually a pill taken once by mouth, damages or destroys thyroid cells that produce excess thyroid hormone. This process may take a few weeks or months. The thyroid gland is reduced in size, and the amount of hormone produced is also reduced. People given this treatment commonly become hypothyroid, which can be treated with medication.10 Surgery. Surgery may remove all or part of the thyroid gland to cure hyperthyroidism. This treatment often results in hypothyroidism. To maintain adequate levels of thyroid hormone in the body, daily treatment with thyroid hormone replacement will be required after surgery. Beta-blockers. These drugs help reduce some of the symptoms of hyperthyroidism, such as rapid heart rate and nervousness. 2 What you should know about hyperthyroidism and the most common cause, Graves’ disease managing my thyroid How can I manage the health of my thyroid? 1.Pay attention to how you feel and report symptoms to your doctor. If you are a woman, older than age 60, have an autoimmune disease (such as type 1 diabetes or rheumatoid arthritis), have a family history of thyroid disease, have had surgery, radiation therapy, or are pregnant, you may need to discuss your thyroid function with your doctor. 2.If you suspect that you may have thyroid disease, ask your doctor about a TSH test. If you have concerns and symptoms of thyroid disease, TSH levels should be measured. Tips on taking medication If you have hyperthyroidism that is treated with surgery or radioactive iodine, you may develop hypothyroidism after treatment.9 If you become hypothyroid and thyroid hormone replacement is prescribed, consider the following advice: 1.Take your medication every day, as prescribed. 2.Take your medications at the same time every day. If you’re taking other medications, prescribed or over-the-counter products, including vitamin supplements, consult with your doctor. 3.Tell your doctor if you stop taking one of your regular medications or start taking a new one. 3.If you have thyroid disease, follow your doctor’s directions. Take your medications exactly as prescribed by your doctor. 4.Have your thyroid function checked every year. An annual TSH test can confirm if your thyroid is functioning normally. The take-home message Having a thyroid disease such as hyperthyroidism may require you to take anti-thyroid medications, undergo special treatment procedures, and see your doctor for frequent follow-up checks. Over time, you may require daily thyroid hormone replacement pills, and you should continue to visit your doctor at least once a year for a checkup. References: 1. The Cleveland Clinic. Thyroid disease. http://www.clevelandclinic.org/health/health-info/ docs/2000/2011.asp?index=8541. Accessed July 15, 2011. 2. AACE Thyroid Task Force. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the evaluation and treatment of hyperthyroidism and hypothyroidism. Endocrinol Pract. 2002;8:457-469. 3. Lab tests online: TSH. http:// www.labtestsonline.org/understanding/analytes/tsh/test.html. Accessed July 15, 2011. 4. EndocrineWeb. Hyperthyroidism: overactivity of the thyroid gland. Part 3: making the diagnosis. http://www.endocrineweb.com/ hyper3.html. Accessed July 15, 2011. 5. Reid J, Wheeler S. Hyperthyroidism: diagnosis and treatment. Am Fam Physician. 2005;72:623-630. 6. Winsa B, Adami HO, Bergstrom R, et al. Stressful life events and Graves’ disease. Lancet. 1991;338(8781):1475-1479. 7. American Thyroid Association. Graves’ Disease FAQ. http://www.thyroid. org/patients/brochures/GravesFAQ.pdf. Accessed July 15, 2011. 8. American Thyroid Association. Thyroiditis FAQ. http://www.thyroid.org/patients/brochures/ThyroiditisFAQ.pdf. Accessed July 15, 2011. 9. American Thyroid Association. Hyperthyroidism FAQ. http://www.thyroid.org/patients/brochures/HyperthyroidismFAQ. pdf. Accessed July 15, 2011. 10. American Thyroid Association. Hypothyroidism FAQ. http://www.thyroid.org/ patients/brochures/HypothyroidismFAQ.pdf. Accessed July 15, 2011. This pamphlet is provided to you by Abbott. ©2011 Abbott Laboratories Abbott Park, IL 60064 605-640911 June 2011 Printed in U.S.A.