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What is Graves' disease?

Dr. Jeanne Morrison, PhD
Family Practitioner

Graves' disease is a condition that causes your thyroid to be overactive and produce too many hormones. Graves' disease is an autoimmune condition where your immune system attacks your thyroid. In many cases, people with Graves' disease develop a goiter.

 

Graves' disease, also known as toxic diffuse goiter, is the most common cause of hyperthyroidism in the United States. Hyperthyroidism is a disorder that occurs when the thyroid gland makes more thyroid hormone than the body needs.

The thyroid gland is a small, butterfly-shaped gland in the front of the neck below the larynx, or voice box. The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Thyroid hormones affect metabolism, brain development, breathing, heart and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, and cholesterol levels.

Thyroid hormone production is regulated by another hormone called thyroid-stimulating hormone (TSH), which is made by the pituitary gland located in the brain.

Graves' disease is an autoimmune disorder, which means that the body's immune system acts against its own healthy cells and tissues. In Graves' disease, the immune system makes antibodies called thyroid-stimulating immunoglobulin (TSI) that attach to thyroid cells. TSI mimics the action of TSH and stimulates the thyroid to make too much thyroid hormone. Sometimes, antibodies can instead block thyroid hormone production, leading to a confusing clinical picture. The diagnosis and treatment of Graves' disease is often performed by an endocrinologist-a doctor who specializes in the body's hormone-secreting glands.

This answer is based on source information from the National Endocrine and Metabolic Diseases Information Service.

The thyroid gland, located in the front of the neck, produces hormones that help regulate your body’s metabolism (the process in which the body transforms food into energy).
In a small number of people, the thyroid gland malfunctions and produces more hormones than the body needs. This is called hyperthyroidism, or Graves’ disease. 
The overproduction of thyroid hormones in Graves’ disease can cause various eye and vision problems.
Dr. Jack Merendino, MD
Endocrinology Diabetes & Metabolism
Graves’ disease is one of the most common causes of hyperthyroidism, meaning an overactive  thyroid.  It helps to understand a little about the normal thyroid before trying to understand Graves’ disease.
The thyroid is under control of another endocrine organ—the  pituitary gland.  The pituitary makes a hormone called “thyroid stimulating hormone,” usually called TSH, that in turn causes the thyroid to make more thyroid hormone and release it into the bloodstream.  TSH triggers an increase in thyroid hormone by chemically attaching to what is termed a “receptor” molecule on the thyroid cells.  Scientists often draw an analogy to a lock and key, where the TSH is the key and the receptor is the lock.  Just as turning the key in your car’s ignition causes the car to start, so TSH attaching to its receptor causes the thyroid cells to release more thyroid  hormone into the bloodstream.  Just as a key will only turn a specific lock, the TSH receptor will only respond to TSH.  Most hormones work in this way.
Graves’ disease is an autoimmune disorder, meaning that it results from the immune system reacting to normal body tissue as though it is foreign to the body, like a virus that is causing infection.  As part of this immune reaction, the body makes antibody molecules.  These are proteins that attach to foreign organisms and help the immune system destroy them.  In an autoimmune disorder, the antibodies attach to normal body tissues and cause damage.  Two of the most common autoimmune problems affect the thyroid: Graves’ disease and Hashimoto's thyroiditis.  
In Graves’ disease one of the types of antibodies that is made has a unique property: part of the molecule has a shape that exactly mimics TSH.  This means that the antibody can chemically attach to the TSH receptor on the thyroid cell and can trigger the same reaction on the part of the thyroid  cell as TSH does.  In other words, the antibody causes the thyroid cell to release more thyroid hormone.  Unlike normal TSH, however, where the amount is carefully controlled by the pituitary gland, the antibody is made in amounts that cause far too much stimulation of the TSH receptor.  The result is that the thyroid gland releases far more thyroid hormone than normal, resulting in hyperthyroidism.  

Graves’ Disease is an autoimmune disorder where the body makes antibodies which attack the thyroid, resulting in overproduction of thyroid hormone. As a result, the patient becomes hyperthyroid(overactive thyroid).

Additional tests that your physician may order include: a radioactive iodine uptake scan, thyroid function blood tests, and blood tests for antibodies which act on the thyroid causing hormone production or release.

In addition to over activity of the thyroid gland, patients may also have symptoms of bulging eyes and/or swelling of the fronts of the lower legs with associated thickening of the skin.

For more information go the endocrinediseases.org: Hyperthyroidism

An overactive thyroid is the most common cause of hyperthyroidism and can be caused by Graves' disease (also known as diffuse toxic goiter or when the whole thyroid is hyperactive), toxic multinodular goiter (when more than one nodule is hyperactive), or a toxic nodule (when just one nodule is hyperactive). Approximately 1 million patients in the United States have Graves' disease, the most common cause of hyperthyroidism. Graves’ disease is an auto-immune process where the body creates antibodies to the thyroid that then attach to the thyroid and “turn it on” thus causing the thyroid to release more thyroid hormone than normal and thus making the patient hyperthyroid.

 

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.