Hyperthyroidism

Hyperthyroidism is an endocrine disease in which the thyroid gland produces excessive amounts of thyroid hormones. Thyrotoxicosis is a related condition that occurs due to elevated levels of thyroid hormones from any cause and therefore includes hyperthyroidism, though the two terms are sometimes used interchangeably. Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems, a fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, hand tremor, and weight loss, though symptoms are typically less severe in the elderly and during pregnancy. An uncommon but life-threatening complication is thyroid storm, in which an event such as an infection results in worsening symptoms such as confusion and a high temperature that often results in death. The opposite condition, hypothyroidism, occurs when the thyroid gland does not make enough thyroid hormone.