
What is Grave’ Disease?
Graves' disease (GD) is an autoimmune thyroid disorder that primarily affects the thyroid gland, causing hyperthyroidism. It may also affect the eyes, causing Graves' ophthalmopathy (thyroid eye disease or TED); the skeletal muscles causing myopathy or muscle weakness; and the skin, causing pretibial myxedema and acropachy.
There are many GD variants or subtypes, and each individual case of GD is unique. Graves' disease is caused by stimulating TSH receptor antibodies, which are also known as thyroid stimulating immunoglobulins or TSI. These antibodies activate receptors on the surface of thyroid cells, ordering thyroid cells to produce more thyroid hormone. Like a key opening a lock, these antibodies cause a sustained increase in thyroid hormone levels.
Graves' disease primarily targets women between the ages of 30-50. However, it also affects men, and it can affect individuals of any age. GD can also affect muscle, causing muscle weakness, and it can affect heart muscle. See "thyroid storm" on the symptoms page.
Patients with pretibial myxedema (PTM) may rarely develop a soft tissue disorder known as acropachy that primarily affects the fingers and toes. GD patients may also exhibit symptoms of clubbing which is different than acropachy. See symptoms page to learn more about the skin disorders associated with GD.
As mentioned, the stimulating thyrotropin (or TSH) receptor antibodies seen in Graves' disease are also called thyroid stimulating immunoglobulins (TSI). These antibodies are directly responsible for the hyperthyroidism of Graves' disease. Acting in place of TSH, they direct the thyroid gland to keep producing and secreting excess thyroid hormone. See Page describing Thyroid Laboratory Tests.
TSI activate the TSH receptor on thyroid cells, mimicking the action of TSH, a hormone released by the pituitary gland. Normally, TSH stimulates the thyroid gland to produce and release thyroid hormone. Bypassing all normal regulatory controls, TSI cause the thyroid gland to release excess thyroid hormone, causing hyperthyroidism. TSI also stimulate orbital cells, causing Graves' ophthalmopathy and they stimulate dermal cells, causing pretibial myxedema.
TSH is a pituitary hormone which regulates thyroid hormone levels in the blood. The concentration of TSH present in the blood is generally a good indicator of thyroid status, and levels of TSH are often used to diagnose thyroid disorders.
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