Hypothyroidism is a condition in which the thyroid gland does not produce adequate amounts of thyroid hormone.
The thyroid gland is a small endocrine gland located in the lower neck. It produces thyroid hormone under regulation by the brain and the pituitary gland. Thyroid hormone, which is released into the body, regulates multiple body functions. It is important in maintaining normal metabolism. Thyroid hormone also helps maintain normal cholesterol balance, heart function, and brain function. Almost every system of the body is affected by hypothyroidism.
Hypothyroidism is most commonly caused by an autoimmune disorder. An autoimmune disorder is a condition in which the body produces antibodies that attack its own cells for no known reason. Hashimoto's thyroiditis is an example of an autoimmune disorder that attacks the thyroid gland. Over time, this makes the thyroid gland unable to produce normal amounts of thyroid hormone.
Some individuals have an overactive thyroid, a condition known as hyperthyroidism. Medications can be given to destroy a portion of an overactive thyroid. If too much medication is given, the person can develop low thyroid function, or hypothyroidism. Surgery to remove the thyroid gland in someone with a condition such as thyroid cancer can also cause hypothyroidism.