The overproduction of thyroid hormones by an overactive thyroid gland. The most common form of hyperthyroidism is Graves’ disease, which is an autoimmune disorder. Less commonly, the condition is associated with the development of enlarged nodules within the thyroid gland. The characteristic signs of hyperthyroidism include weight loss, increased appetite, increased sweating, intolerance to heat, a rapid heart-rate, and protruding eyes. In severe cases, the thyroid gland often becomes enlarged (see goitre) and there is physical and mental hyperactivity and muscle wasting. The diagnosis of hyperthyroidism is confirmed by measuring the level of thyroid hormones present in the blood. The condition can be treated with drugs that inhibit the production of thyroid hormones or by removal of part of the thyroid gland.


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