Thyroid Disease: Understanding hypothyroidism and hyperthyroidism

Many people diagnosed with a thyroid condition are surprised that such a tiny gland can have such a profound impact on overall health and well-being. But the thyroid gland plays an enormous role in human health. Throughout life, this busy gland is constantly producing hormones that influence metabolism. When disease causes your thyroid gland to slack off and underproduce thyroid hormone, or overwork and produce too much of it, you'll know something isn't right. This Special Health Report will help you recognize the symptoms and find the right treatment before you experience the long-term effects of this common condition.

Thyroid Disease: Understanding hypothyroidism and hyperthyroidism Cover

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Would you know it if your thyroid gland slowed production of thyroid hormone? Or if it sped up? The symptoms are hard to spot. An out-of kilter thyroid gland causes a variety of puzzling symptoms and many people and doctors mistake them for signs of another disease or normal aging. More than 12 million Americans have thyroid disease, many of whom don’t realize it. The Special Health Report, Thyroid Disease: Understanding hypothyroidism and hyperthyroidism explains in easy-to-understand language how to know if your thyroid gland is not functioning as it should and what treatment to follow if your levels are too high or too low.

Prepared by the editors of Harvard Health Publications in consultation with Jeffery R. Garber, M.D., Associate Professor of Medicine, Harvard Medical School; Chief of Endocrinology, Harvard Vanguard Medical Associates; Physician, Beth Israel Deaconess Medical Center; Associate Physician, Brigham and Women’s Hospital. 49 pages. (2012)

  • Your thyroid gland
    • How the thyroid gland works
    • When things go wrong
    • Slowing down
    • Revving up
    • Racing and burning out
  • Special section: Who gets thyroid disease?
  • Hypothyroidism
    • Signs and symptoms
    • What causes hypothyroidism?
    • Diagnosing hypothyroidism
    • Treating hypothyroidism
    • Common questions from patients
  • Hyperthyroidism
    • Signs and symptoms
    • What causes hyperthyroidism?
    • Diagnosing hyperthyroidism
    • Treating hyperthyroidism
    • Mild hyperthyroidism
    • Treating Graves’ eye disease
  • You and your doctor
    • Your primary care doctor
    • Finding a specialist
    • Finding a surgeon
    • Other specialists
  • Living well with thyroid disease
    • Regular check-ups
    • Healthy eating and exercise
  • Resources
  • Glossary

Dear Reader,

If you are like many of my patients diagnosed with a thyroid condition, you might be surprised that such a tiny gland can have such a profound impact on your overall health and well-being. But it’s no wonder, when you consider the enormous job your thyroid has. Throughout life, this busy gland is constantly producing hormones that influence your metabolism. So when disease causes your thyroid gland to slack off and underproduce thyroid hormone, or overwork and produce too much of it, you’ll know something isn’t right.

The symptoms of thyroid diseases are so wide-ranging—affecting your mood, energy, body temperature, weight, heart, and more—that it may be difficult to get the correct diagnosis right away. The risk of thyroid disease increases with age. Yet thyroid disease is most difficult to detect in people over 60 because it often masquerades as another illness, such as heart disease, depression, or dementia. Misleading symptoms are one reason many Americans who have thyroid disease—mostly women—do not yet know they have it.

Estimates of how many people have thyroid disease vary widely, ranging from 10 million to 30 million. The most reliable number available comes from the third U.S. National Health and Nutrition Examination Survey (NHANES III) of people ages 12 and older. The survey showed that nearly 6% of the U.S. population has thyroid disease. Within this group, about 80% have hypothyroidism. A much smaller number, close to 20%, have hyperthyroidism. But the population is aging, and the proportion of people with thyroid conditions is increasing.

Diagnosing thyroid conditions can be tricky, and, in certain circumstances, so is treating them. This report gives you an inside look at treatment guidelines, based on the most up-to-date medical research and developed by leading thyroid experts from the American Association of Clinical Endocrinologists (AACE) and the American Thyroid Association (ATA). As chair of the task force that created the hypothyroidism treatment guidelines and as a panelist on the corresponding hyperthyroidism task force, I am happy to share my insights on some of the key points and controversies surrounding the best way to manage your thyroid condition.

I am confident that with proper treatment, your thyroid problem can be successfully managed. My hope is that this report will help you work closely with your doctor to bring your thyroid hormone levels back to normal, so that you can go about living your life to its fullest.



Jeffrey R. Garber, M.D.

Medical Editor

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This was excellent! I am a nurse -- but I still learned a LOT from this publication. Plus, it was written for a lay person to be able to read and understand. I HIGHLY recommend this for anybody facing Thyroid issues. It will make a difference in your life.
I had a thyroid op in February 1995. The one with a "solitary toxic adenoma." I only wish that I knew then what I know now after reading this Special Health Report. The Glossary is great!/LA
I have done a lot of reading on hypothyroidism and I found much new helpful information in this report.