Hyperthyroidism Information for Patients

What is hyperthyroidism? tMuscle weakness, especially of the upper arms and thighs Hyperthyroidism develops when the body tLoose and frequent bowel movements is exposed to excessive amounts of thyroid tThin and delicate skin hormone. This disorder occurs in almost 1% of all Americans and affects women 5 to 10 tChange in menstrual pattern times more often than men. In its mildest form, tIncreased likelihood for miscarriage hyperthyroidism may not cause recog nizable tProminent “stare” of the eyes symptoms. More often, however, the symptoms are discomforting, disabling, or even life- tProtrusion of the eyes, with or without double threatening. vision (in patients with Graves’ disease) tIrregular heart rhythm, especially in patients older than 60 years of age What are the symptoms tAccelerated loss of calcium from bones, which of hyperthyroidism? increases the risk of osteoporosis and fractures

When hyperthyroidism develops, a goiter (enlargement of the thyroid) is usually present What are the causes and may be associated with some or many of of hyperthyroidism? the following symptoms:

tFast heart rate, often more than 100 beats per Graves’ disease minute Graves’ disease (named after Irish physician tNervousness, anxiety, or an irritable and Robert Graves) is an autoimmune disorder quarrelsome feeling that frequently results in thyroid enlargement and hyperthyroidism. In a minority of patients, tTrembling hands swelling of the muscles and other tissues around tWeight loss, despite eating the same amount the eyes may develop, causing eye prominence, or even more than usual discomfort or double vision. Like other tIntolerance of warm temperatures and autoimmune diseases, this condition tends to increased likelihood to perspire affect multiple family members. It is much more tLoss of scalp hair common in women than in men, and tends to occur in younger patients. tRapid growth of fingernails and tendency of fingernails to separate from the nail bed

Prepared by the American Association of Clinical Endocrinologists (AACE), a not-for-profit national organization of highly qualified specialists in hormonal and metabolic disorders whose primary professional activities focus on providing high-quality specialty care to patients with endocrine problems such as thyroid disease. © 2004 AACE - Permission is granted for reproduction of this publication. Toxic multinodular goiter Silent thyroiditis Transient (temporary) hyperthyroidism can be Multiple nodules in the thyroid can produce caused by silent thyroiditis, a condition which excessive thyroid hormone, causing appears to be the same as postpartum thyroiditis hyperthy roidism. Often diagnosed in patients but not related to pregnancy. It is not accompanied over the age of 50, this disorder is more likely to by a painful thyroid gland. affect heart rhythm. In many cases, the person has had the goiter for many years before it Excessive iodine ingestion becomes overactive. Various sources of high iodine concentrations, such as kelp tablets, some expectorants, amiodarone Toxic nodule (Cordarone, Pacerone – a medication used to treat A single nodule or lump in the thyroid can certain problems with heart rhythms) and x-ray also produce more thyroid hormone than the dyes, may occasionally cause hyperthyroidism in body requires and lead to hyperthyroidism. This certain patients. disorder is not familial. Overmedication with thyroid hormone Subacute thyroiditis Patients who receive excessive thyroxine This condition of unknown cause is replace ment treatment can develop char ac ter ized by painful thyroid gland hyperthyroidism. They should have their thyroid enlargement and inflammation, which results hormone dosage eval uated by a physician at least in the release of large amounts of thyroid once each year and should NEVER give themselves hormones into the blood. Fortunately, this “extra” doses. condition usually resolves spontaneously. The thyroid usually heals itself over several months, How is hyperthyroidism but often not before a temporary period of low diagnosed? thyroid hormone production (hypothyroidism) Characteristic symptoms and physical signs of occurs. hyperthyroidism can be detected by a physician. In addition, tests can be used to confirm the diagnosis Postpartum thyroiditis and to determine the cause. 5% to 10% of women develop mild to moderate hyperthyroidism within several months of giving TSH (thyroid-stimulating hormone birth. Hyperthyroidism in this condition usually or thyrotropin) test lasts for approximately 1-2 months. It is often A low TSH level in the blood is the most accurate followed by several months of hypothyroidism, indicator of hyperthyroidism. The body shuts but most women will recover normal thyroid off production of this pituitary hormone when function even tually. In some cases, however, the thyroid gland even slightly overproduces the thyroid gland does not heal, so the thyroid hormone. If the TSH level is low, it is very hypothyroidism becomes permanent and requires important to also check thyroid hormone levels to lifelong thyroid hormone replacement. confirm the diagnosis of hyperthyroidism

Prepared by the American Association of Clinical Endocrinologists (AACE), a not-for-profit national organization of highly qualified specialists in hormonal and metabolic disorders whose primary professional activities focus on providing high-quality specialty care to patients with endocrine problems such as thyroid disease. © 2004 AACE - Permission is granted for reproduction of this publication. Other tests Antithyroid drugs In the United States, 2 drugs are available for tFree T4 (thyroxine) and Free T3 (triiodothyronine) treating hyperthyroidism: propylthiouracil (PTU) - the active thyroid hormones in the blood. and methimazole (Tapezole). These medications When hyperthyroidism develops, free T4 and T3 control hyperthyroidism by slowing thyroid levels rise above previous values in that specific hormone production, and are frequently used patient (although they may still fall within the for several months after the initial diagnosis of normal range for the general population), and hyperthyroidism to normalize the thyroid hormone are often considerably elevated. levels. Some patients with hyper thyroidism caused by Graves disease experi ence a spontaneous or tTSI (thyroid-stimulating immunoglobulin) - a natural remis sion of hyperthyroidism after a 12 to substance often found in the blood when Graves’ 18 month course of treatment with these drugs, disease is the cause of hyperthyroidism. This and may sometimes avoid permanent under act ivity test is ordered infrequently, since it rarely affects of the thyroid (hypothyroidism), which often occurs treatment decisions. as a result of using the other methods of treating hyperthyroidism. Unfort unately, the remission is tRadioactive iodine uptake (RAIU - a frequently only temp orary, with the hyperthyroidism measure ment of how much iodine the thyroid recurring after several months or years off gland can collect) and thyroid scan (a thyroid medication and requir ing additional treatment, scan shows how the iodine is distributed so relatively few patients are treated solely with throughout the thyroid gland). This information antithyroid medication in the United States. can be useful in determining the cause of hyperthyroidism and ultimately its treatment. Antithyroid drugs may cause an allergic reaction in about 5% of patients who use them. This usually Sometimes a general physician can diagnose and occurs during the first 6 weeks of drug treatment. treat the cause of hyperthyroidism, but assistance Such a reaction may include rash, hives, fever, or is often needed from an endocrinologist, a physician joint pain, but after discontinuing use of the drug, who specializes in managing thyroid disease. the symptoms resolve within 1 – 2 weeks, and there is no permanent damage.

A more serious effect, but occurring in only about How is hyperthyroidism 1 in 250-500 patients during the first 4 to 8 weeks of treatment, is a rapid decrease of white blood treated? cells in the bloodstream. This could increase suscep ti bil ity to serious infection. Symptoms such as a sore throat, joint aches, infection, or fever Before the development of current treatment should be reported promptly to your physician, and options, the death rate from hyperthyroidism was as a blood cell count should be done immediately. In high as 50%. Now several effective treatments are nearly every case, when a person stops using the available, and with proper man agement, death from med i ca tion, the white blood cell count returns to hyperthyroidism is rare. Deciding which treatment is normal. best depends on what caused the hyperthyroidism, its severity, and other conditions present. A Very rarely, antithyroid drugs may cause liver physician who is experienced in the manage ment of problems, which can be detected by monitoring thyroid diseases can confidently diagnose the cause of hyperthyroidism and prescribe and manage the blood tests. Your physician should be contacted if best treatment program for each patient. there is yellowing of the skin (“jaundice”), fever, loss of appetite, or abdominal pain.

Iodine is an essential ingredient in the pro duc tion of Although seldom used now as the preferred treatment thyroid hormone. Each molecule of thyroid hormone for hyperthyroidism, operating to remove most of the contains either 4 (T4) or 3 (T3) molecules of iodine. thyroid gland may occa sion ally be recommended in Since most over active thyroid glands are quite hungry certain situations, such as a pregnant woman with severe for iodine, it was discovered in the 1940’s that the disease in whom radioiodine would not be safe for the thyroid could be “tricked” into destroying itself by simply baby, removal of a clinically suspicious thyroid nodule feeding it radioactive iodine. The radioactive iodine is coexisting with hyperthyroidism, or for rare patients with given by mouth, usually in capsule form, and is quickly Graves disease who have severe protrusion of their eyes. absorbed from the bowel. It then enters the thyroid In such patients, permanent hypothyroidism usually cells from the bloodstream and gradually destroys them. results, and lifelong thyroxine replace ment is required. Maximal benefit is usually noted within 3 to 6 months. Other treatments It is not possible to reliably eliminate “just the right A drug from the class of beta-adrenergic blocking agents amount” of the diseased thyroid gland, since the effects (which decrease the effects of excess thyroid hormone) of the radioiodine are slowly progressive on the thyroid may be used temporarily to control hyper thyroid cells. There fore, most endocrinologists strive to completely symptoms while one of the above- mentioned treatments destroy the diseased thyroid gland with a single dose of becomes effective. In cases where hyperthyroidism is radioiodine. This results in the intentional development caused by thyroiditis or excessive ingestion of either of an underactive thyroid state (hypothyroidism), which iodine or thyroid hormone, this may be the only type of is easily, predictably and inexpensively corrected by treatment required. Of course, taking too much of either lifelong daily use of oral thyroid hormone replacement substance should also be corrected. therapy. Although every effort is made to calculate the correct dose of radio iodine for each patient, not every Appropriate management of hyperthyroidism requires treatment will successfully correct the hyperthyroidism, careful evaluation and ongoing care by a physician particularly if the goiter is quite large, and a second dose experienced in the treatment of this complex condition. of radioactive iodine is occasion ally needed.

In the 50+ years and hundreds of thousands of patients (including a former President of the United States and Compliments of: his wife!) in which radio iodine has been used, no serious compli cations have been reported. Since the treatment appears to be extraordinarily safe, simple, and reliably effec tive, it is considered by most thyroid specialists in the United States to be the treatment of choice for those types of hyperthyroidism caused by over pro duc tion of

thyroid hormones. Supported by an unrestricted educational grant from Abbott Laboratories

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS 1000 Riverside Avenue, Suite 205 • Jacksonville, FL 32204