Hyperthyroidism refers to overactivity of the thyroid gland resulting in excessive secretion of thyroid hormones. The thyroid gland produces thyroid hormones which regulate metabolism. Common causes of hyperthyroidism include Graves' disease, multinodular goiter, and thyroiditis. Signs and symptoms include nervousness, palpitations, heat intolerance, tremors, and weight loss. Diagnosis involves thyroid function tests and scans. Treatment options include anti-thyroid medications, radioactive iodine, and surgery. Nursing care focuses on managing nutrition, activity tolerance, risk for injury, hyperthermia, and social interaction issues.