Hashimoto's Disease

Hashimoto’s Disease

National Endocrine and Metabolic Diseases Information Service

What is Hashimoto’s thyroid hormone for the body’s needs. Thyroid hormones regulate metabolism— disease? the way the body uses energy—and affect Hashimoto’s disease, also called chronic nearly every organ in the body. Without lymphocytic thyroiditis or autoimmune enough thyroid hormone, many of the body’s thyroiditis, is an autoimmune disease. An functions slow down. Hashimoto’s disease is autoimmune disease is a disorder in which the most common cause of hypothyroidism the body’s immune system attacks the body’s in the United States.1 own cells and organs. Normally, the immune system protects the body from infection by Read more in Hypothyroidism at identifying and destroying bacteria, viruses, www.endocrine.niddk.nih.gov. and other potentially harmful foreign substances. What is the thyroid? In Hashimoto’s disease, the immune The thyroid is a 2-inch-long, butterfly-shaped system attacks the thyroid gland, causing gland weighing less than 1 ounce. Located inflammation and interfering with its in the front of the neck below the larynx, or ability to produce thyroid hormones. voice box, it has two lobes, one on either side Large numbers of white blood cells called of the windpipe. lymphocytes accumulate in the thyroid. The thyroid is one of the glands that make Lymphocytes make the antibodies that start up the endocrine system. The glands of the autoimmune process. the endocrine system produce and store Hashimoto’s disease often leads to reduced hormones and release them into the thyroid function, or hypothyroidism. bloodstream. The hormones then travel Hypothyroidism is a disorder that occurs through the body and direct the activity of when the thyroid doesn’t make enough the body’s cells.

1Lee SL. Hashimoto thyroiditis. Medscape website. http://emedicine.medscape.com/ article/120937-overview. Updated February 25, 2013. Accessed November 14, 2013. The thyroid makes two thyroid hormones, What are the symptoms triiodothyronine (T3) and thyroxine (T4). T3 of Hashimoto’s disease? is the active hormone and is made from T4. Thyroid hormones affect metabolism, brain Many people with Hashimoto’s disease have development, breathing, heart and nervous no symptoms at first. As the disease slowly system functions, body temperature, muscle progresses, the thyroid usually enlarges strength, skin dryness, menstrual cycles, and may cause the front of the neck to look weight, and cholesterol levels. swollen. The enlarged thyroid, called a goiter, may create a feeling of fullness in the Thyroid-stimulating hormone (TSH), which throat, though it is usually not painful. After is made by the pituitary gland in the brain, many years, or even decades, damage to the regulates thyroid hormone production. thyroid causes it to shrink and the goiter to When thyroid hormone levels in the blood disappear. are low, the pituitary releases more TSH. When thyroid hormone levels are high, the Not everyone with Hashimoto’s disease pituitary decreases TSH production. develops hypothyroidism. For those who do, the hypothyroidism may be subclinical—mild and without symptoms, especially early in its course. With progression to hypothyroidism, Pituitary people may have one or more of the gland following symptoms: • fatigue • weight gain • cold intolerance • joint and muscle pain • constipation, or fewer than three bowel TSH movements a week • dry, thinning hair • heavy or irregular menstrual periods Thyroid and problems becoming pregnant • depression • memory problems • a slowed heart rate T3-T4

The thyroid makes two thyroid hormones, T3 and T4. TSH, which is made by the pituitary gland in the brain, regulates thyroid hormone production.

2 Hashimoto’s Disease Who is more likely to • rheumatoid arthritis, a disease that causes pain, swelling, stiffness, and develop Hashimoto’s loss of function in the joints when the disease? immune system attacks the membrane Hashimoto’s disease is much more common lining the joints. in women than men. Although the disease • Addison’s disease, in which the adrenal often occurs in adolescent or young women, glands are damaged and cannot produce it more commonly appears between 30 and enough of certain critical hormones. 50 years of age.1 • type 1 diabetes, in which the pancreas Hashimoto’s disease tends to run in families. is damaged and can no longer produce Researchers are working to identify the gene insulin, causing high blood glucose, also or genes that cause the disease to be passed called blood sugar. from one generation to the next. • pernicious anemia, a type of anemia Possible environmental factors are also caused by not having enough vitamin being studied. For example, researchers B12 in the body. In anemia, the number have found that consuming too much iodine of red blood cells is less than normal, may inhibit thyroid hormone production resulting in less oxygen carried to the in susceptible individuals. Chemicals body’s cells and extreme fatigue. released into the environment, such as • celiac disease, a form of gastrointestinal pesticides, along with certain medications gluten sensitivity, an autoimmune or viral infections may also contribute to disorder in which people cannot tolerate autoimmune thyroid diseases. gluten because it will damage the lining People with other autoimmune diseases of the small intestine and prevent are more likely to develop Hashimoto’s adsorption of nutrients. Gluten is a disease. The opposite is also true—people protein found in wheat, rye, and barley with Hashimoto’s disease are more likely to and in some products. develop other autoimmune diseases. These • autoimmune hepatitis, or nonviral liver diseases include inflammation, a disease in which the • vitiligo, a condition in which some areas immune system attacks liver cells. of the skin lose their natural color.

3 Hashimoto’s Disease How is Hashimoto’s disease –– anti-thyroperoxidase (TPO) antibodies, which attack an enzyme diagnosed? called thyroperoxidase in thyroid Diagnosis begins with a physical exam cells that helps convert T4 to T3. and medical history. A goiter, nodules, Having TPO autoantibodies in the or growths may be found during a blood means the body’s immune physical exam, and symptoms may suggest system attacked the thyroid tissue hypothyroidism. Health care providers will in the past. Most people with then perform blood tests to confirm the Hashimoto’s disease have these diagnosis. A blood test involves drawing antibodies, although people whose blood at a health care provider’s office or a hypothyroidism is caused by other commercial facility and sending the sample conditions do not. to a lab for analysis. Diagnostic blood tests may include the A health care provider may also order imaging tests, including an ultrasound or a • TSH test. The ultrasensitive TSH test computerized tomography (CT) scan. is usually the first test performed. This test detects even tiny amounts of TSH • Ultrasound. Ultrasound uses a device, in the blood and is the most accurate called a transducer, that bounces safe, measure of thyroid activity available. painless sound waves off organs to Generally, a TSH reading above normal create an image of their structure. A means a person has hypothyroidism. specially trained technician performs the procedure in a health care • T4 test. The T4 test measures the actual provider’s office, an outpatient center, amount of thyroid hormone circulating or a hospital, and a radiologist—a in the blood. In hypothyroidism, the doctor who specializes in medical level of T4 in the blood is lower than imaging—interprets the images; a normal. patient does not need anesthesia. • antithyroid antibody test. This test The images can show the size and looks for the presence of thyroid texture of the thyroid, as well as autoantibodies, or molecules produced a pattern of typical autoimmune by a person’s body that mistakenly inflammation, helping the health care attack the body’s own tissues. Two provider confirm Hashimoto’s disease. principal types of antithyroid antibodies The images can also show nodules or are growths within the gland that suggest a –– anti-TG antibodies, which attack malignant tumor. a protein in the thyroid called thyroglobulin

4 Hashimoto’s Disease • CT scan. CT scans use a combination ensuring a steady supply of thyroid of x rays and computer technology to hormone throughout the day. The thyroid create images. For a CT scan, a health preparations made with animal thyroid are care provider may give the patient a not considered as consistent as synthetic solution to drink and an injection of a thyroid (Levothyroxine) and rarely special dye, called contrast medium. prescribed today. CT scans require the patient to lie on Health care providers routinely test the a table that slides into a tunnel-shaped blood of patients taking synthetic thyroid device where the x rays are taken. An hormone and adjust the dose as necessary, x-ray technician performs the procedure typically based on the result of the TSH in an outpatient center or a hospital, test. Hypothyroidism can almost always and a radiologist interprets the images. be completely controlled with synthetic The patient does not need anesthesia. thyroxine, as long as the recommended dose In some cases of Hashimoto’s disease, is taken every day as instructed. a CT scan is used to examine the placement and extent of a large goiter, and to show a goiter’s effect on nearby How does Hashimoto’s structures. disease affect pregnant Read more in Thyroid Tests at women? www.endocrine.niddk.nih.gov. During pregnancy, hypothyroidism is usually caused by Hashimoto’s disease and occurs in How is Hashimoto’s disease three to five out of every 1,000 pregnancies.2 treated? Uncontrolled hypothyroidism raises the chance of miscarriage, premature birth, Treatment generally depends on whether stillbirth, and preeclampsia—a dangerous the thyroid is damaged enough to cause rise in blood pressure in late pregnancy. hypothyroidism. In the absence of hypothyroidism, some health care providers Untreated hypothyroidism during pregnancy treat Hashimoto’s disease to reduce the size may also affect the baby’s growth and brain of the goiter. Others choose not to treat the development. Thyroid medications can help disease and simply monitor their patients for prevent these problems and are safe to take disease progression. during pregnancy. Women with Hashimoto’s disease should discuss their condition with Hashimoto’s disease, with or without their health care provider before becoming hypothyroidism, is treated with synthetic pregnant. thyroxine, which is man-made T4. Health care providers prefer to use synthetic T4, Read more in Pregnancy and Thyroid Disease such as Synthroid, rather than synthetic at www.endocrine.niddk.nih.gov. T3, because T4 stays in the body longer,

2Ogunyemi DA. Autoimmune thyroid disease and pregnancy. Medscape website. http://emedicine. medscape.com/article/261913-overview. Updated March 8, 2012. Accessed November 14, 2013. 5 Hashimoto’s Disease Eating, Diet, and Nutrition Points to Remember Iodine is an essential mineral for the thyroid. • Hashimoto’s disease, also called chronic However, people with Hashimoto’s disease lymphocytic thyroiditis or autoimmune may be sensitive to harmful side effects from thyroiditis, is an autoimmune disease. iodine. Taking iodine drops or eating foods • Hashimoto’s disease often leads containing large amounts of iodine—such to reduced thyroid function, or as seaweed, dulse, or kelp—may cause or hypothyroidism. Hypothyroidism is a worsen hypothyroidism. Read more in disorder that occurs when the thyroid Iodine in diet at www.nlm.nih.gov/medlineplus/ doesn’t make enough thyroid hormone ency/article/002421.htm. for the body’s needs. Women need more iodine when they are • Hashimoto’s disease is the most pregnant—about 220 micrograms a day— common cause of hypothyroidism because the baby gets iodine from the in the United States. Many people mother’s diet. Women who are breastfeeding with Hashimoto’s disease have no need about 290 micrograms a day. In the symptoms at first. As the disease slowly United States, about 7 percent of pregnant progresses, the thyroid usually enlarges women may not get enough iodine in their and may cause the front of the neck to 3 diet or through prenatal vitamins. Pregnant look swollen. The enlarged thyroid, women should choose iodized salt—salt called a goiter, may create a feeling supplemented with iodine—over plain salt of fullness in the throat, though it is and take prenatal vitamins containing iodine usually not painful. to ensure this need is met. • Not everyone with Hashimoto’s To help ensure coordinated and safe disease develops hypothyroidism. For care, people should discuss their use of those who do, the hypothyroidism complementary and alternative medical may be subclinical—mild and without practices, including their use of dietary symptoms, especially early in its course. supplements such as iodine, with their health care provider. Tips for talking with health • Hashimoto’s disease is much more care providers are available at the National common in women than men. Although Center for Complementary and Alternative the disease often occurs in adolescent Medicine’s Time to Talk campaign at or young women, it more commonly www.nccam.nih.gov/timetotalk. appears between 30 and 50 years of age.

3Lee SL. Iodine deficiency. Medscape website. http:// emedicine.medscape.com/article/122714-overview. Updated January 27, 2012. Accessed November 14, 2013. 6 Hashimoto’s Disease • Hashimoto’s disease, with or without For More Information hypothyroidism, is treated with synthetic American Academy of Otolaryngology— thyroxine, which is man-made T . 4 Head and Neck Surgery • Women with Hashimoto’s disease 1650 Diagonal Road should discuss their condition with their Alexandria, VA 22314–2857 health care provider before becoming Phone: 703–836–4444 pregnant. Internet: www.entnet.org • Pregnant women should choose iodized American Association of Clinical salt—salt supplemented with iodine— Endocrinologists over plain salt and take prenatal 245 Riverside Avenue, Suite 200 vitamins containing iodine. Jacksonville, FL 32202 • People should discuss their use of Phone: 904–353–7878 dietary supplements, such as iodine, Fax: 904–353–8185 with their health care provider. Internet: www.aace.com American Thyroid Association Hope through Research 6066 Leesburg Pike, Suite 550 The National Institute of Diabetes and Falls Church, VA 22041 Digestive and Kidney Diseases (NIDDK) Phone: 703–998–8890 conducts and supports research into many Fax: 703–998–8893 kinds of disorders, including Hashimoto’s Email: [email protected] disease. Researchers throughout the United Internet: www.thyroid.org States and the world are working to better The Endocrine Society understand, prevent, and treat this disease, 8401 Connecticut Avenue, Suite 900 including those who are trying to identify the Chevy Chase, MD 20815–5817 genes that make some people susceptible to Phone: 1–888–363–6274 or 301–941–0200 autoimmune thyroid diseases. Fax: 301–941–0259 Clinical trials are research studies involving Email: [email protected] people. Clinical trials look at safe and Internet: www.endo-society.org effective new ways to prevent, detect, or Hormone Health Network treat disease. Researchers also use clinical Phone: 1–800–HORMONE trials to look at other aspects of care, such (1–800–467–6663) as improving the quality of life for people Email: [email protected] with chronic illnesses. To learn more about Internet: www.hormone.org clinical trials, why they matter, and how to participate, visit the NIH Clinical Research Trials and You website at www.nih.gov/health/ clinicaltrials. For information about current studies, visit www.ClinicalTrials.gov.

7 Hashimoto’s Disease Acknowledgments National Endocrine Publications produced by the NIDDK are and Metabolic Diseases carefully reviewed by both NIDDK scientists Information Service and outside experts. This publication was reviewed by Leonard Wartofsky, M.D., 6 Information Way M.A.C.P., Washington Hospital Center. Bethesda, MD 20892–3569 Phone: 1–888–828–0904 TTY: 1–866–569–1162 You may also find additional information about this Fax: 703–738–4929 topic by visiting MedlinePlus at www.medlineplus.gov. Email: [email protected] This publication may contain information about Internet: www.endocrine.niddk.nih.gov medications and, when taken as prescribed, the conditions they treat. When prepared, this The National Endocrine and Metabolic publication included the most current information Diseases Information Service is an available. For updates or for questions about any medications, contact the U.S. Food and Drug information dissemination service of the Administration toll-free at 1–888–INFO–FDA National Institute of Diabetes and Digestive (1–888–463–6332) or visit www.fda.gov. Consult your and Kidney Diseases (NIDDK). The health care provider for more information. NIDDK is part of the National Institutes of Health, which is part of the U.S. Department of Health and Human Services. The U.S. Government does not endorse or favor any specific commercial product or company. rade,T The NIDDK conducts and supports proprietary, or company names appearing in this biomedical research. As a public service, the document are used only because they are considered NIDDK has established information services necessary in the context of the information provided. If a product is not mentioned, the omission does not to increase knowledge and understanding mean or imply that the product is unsatisfactory. about health and disease among patients, health professionals, and the public.

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NIH Publication No. 14–6399 February 2014

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