Thyroid Disease 101: The Basics from Mary Shomon, your Guide to Thyroid Disease

The thyroid is a small gland, shaped like a butterfly, located in the lower part of your neck. The function of a gland is to secrete hormones. The main hormones released by the thyroid are triiodothyronine, abbreviated as T3, and thyroxine, abbreviated as T4. These thyroid hormones deliver energy to cells of the body.

What Diseases and Conditions Affect the Thyroid?

The most common problems that develop in the thyroid include:

• Hypothyroidism -- An underactive thyroid.
• Hyperthyroidism -- An overactive thyroid.
• Goiter -- An enlarged thyroid.
• Thyroid Nodules -- Lumps in the thyroid gland.
• Thyroid Cancer -- Malignant thyroid nodules or tissue.
• Thyroiditis -- Inflammation of the thyroid.

When the thyroid gland is underactive, improperly formed at birth, surgically removed all or in part, or becomes incapable of producing enough thyroid hormone, a person is said to be hypothyroid. One of the most common causes of hypothyroidism is the autoimmune disease called Hashimoto's disease, in which antibodies gradually target the thyroid and destroy its ability to produce thyroid hormone.

Symptoms of hypothyroidism usually go along with a slowdown in metabolism, and can include fatigue, weight gain, and depression, among others.

• The Hypothyroidism Risks/Symptoms Checklist reviews the key symptoms.
• Quiz: Could You Be Hypothyroid? is a self-test to help you identify risks and symptoms.

When the thyroid gland becomes overactive and produces too much thyroid hormone, a person is said to be hyperthyroid. The most common cause of hyperthyroidism is the autoimmune condition known as Graves' disease, where antibodies target the gland and cause it to speed up hormone production.

• The Hyperthyroidism Checklist looks at the key risks and symptoms.
• Quiz: Could You Be Hyperthyroid? is an interactive self-test.
• FAQ: Common Questions on Hyperthyroidism answers many questions you might have.
• The 10 Things Your Doctor May Not Have Told You About Graves' Disease has additional important information.

Most thyroid dysfunction such as hypothyroidism or hyperthyroidism is due to autoimmune thyroid disease. Autoimmune disease refers to a condition where the body's natural ability to differentiate between its tissues, organs and glands, vs. outside bacteria, viruses or pathogens, becomes disrupted. This causes the immune system to wrongly mount an attack on the affected area, by producing antibodies. In the case of autoimmune thyroid disease, antibodies either gradually destroy the thyroid, or make it overactive.

• To understand the difference between an underactive thyroid and Hashimoto's disease, read: Hashimoto's vs. Hypothyroidism: What's the Difference?
• In some cases, the autoimmune disease itself may warrant treatment, as described in Treatment Can Help Those Who Test Positive for Thyroid Antibodies
• Having one autoimmune disease increases the personal and family risk of other autoimmune diseases. The Autoimmune Disease Checklist looks at various symptoms that are common to these types of diseases.

Sometimes the thyroid becomes enlarged -- due to Hashimoto's disease, Graves' disease, nutritional deficiencies, or other thyroid imbalances. When the thyroid become enlarged, this is known as a goiter.

Some people develop solid or liquid filled cysts, lumps, bumps and tumors -- both benign and cancerous -- in the thyroid gland. These are known as thyroid nodules.

• Sometimes you can find a thyroid lump yourself by performing a Thyroid Neck Check
• All About Thyroid Nodules, Lumps and Goiter helps you understand these problems, how they're diagnosed and treated.
• Biopsy is sometimes needed to rule out cancer in a nodule. Here's a Q&A on Fine Needle Aspiration Biopsy.
• If you get a questionable thyroid biopsy, you may also need a Second Opinion on Thyroid Nodules.

A small percentage of thyroid nodules are cancerous. While thyroid cancer is a rare cancer, it's on the rise. Learn more about thyroid cancer in these articles:

• Thyroid Cancer Facts, Statistics, and How to Do a Thyroid Neck Check
• Thyroid Cancer Risk Factors
• Thyroid Cancer Symptoms
• Thyroid Cancer Diagnosis

When the thyroid becomes inflamed, due to bacterial or viral illness, this is known as thyroiditis. Dr. Stephen Langer has discussed thyroiditis here at the site. It's also important to be aware of the development of some successful thyroiditis treatments.

Treatments

• Surgery is usually performed for thyroid cancer, for some cases of goiter or nodule, and less commonly, as a hyperthyroidism treatment. Read Thyroid Surgery for a detailed overview of what to expect from thyroid surgery.
• Thyroid drugs are an important part of treatment for many patients. Read All About Thyroid Hormone Replacement Drugs, which provides an overview of the key drug treatments. It's also important to know How To Take Your Thyroid Hormone Replacement Medication. There are also controversies in thyroid hormone replacement, including the T4/T3 Thyroid Drug Controversy, and the Armour Thyroid/Desiccated Thyroid Controversy.
• Some conditions involve using radioactive iodine to deactivate the thyroid. Read more about Radioactive Iodine, also known as RAI.

It's important to find the right doctor for your thyroid care, and to work effectively with that practitioner. An endocrinologist is a specialist in endocrine disorder, including thyroid disease. But you'll want to know: Do you really need an endocrinologist?

• Taking the Quiz: What Type of Doctor is Best For You and Your Thyroid Treatment? can help you determine where to start.
• Various directories can help you find thyroid doctors.

• Are you pregnant, trying to conceive, or breastfeeding? Thyroid disease poses particular challenges. Explore the Fertility, Pregnancy and Breastfeeding Information Center for Thyroid Patients.
• Weight problems and difficulty losing weight are unfortunate side effects for many thyroid patients. Start with this helpful Quiz: Is Your Thyroid Making You Fat? to assess your own situation. Then read Losing Weight with a Thyroid Problem has sound information to get you started losing weight, despite a thyroid condition.
• You'll also want to visit the Thyroid Diet and Weight Loss Information Center has dozens of resources to help.
• You'll also want to sign up for the free 4 Weeks to Weight Loss Email Ecourse to help jumpstart your weight loss efforts, and provide you with new ideas for diet and weight loss.

• Sign up for Mary Shomon's free weekly email Thyroid Newsletter, which features the latest news on thyroid disease diagnosis, treatment, and related health issues of interest.
  
• Bookmark the About.com Thyroid Blog -- where you'll find up-to-the-minute information about the latest thyroid news, and links to thyroid information and news here on the site, and around the web.

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