Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone. Symptoms include, but are not limited to, fatigue, increase in appetite, sweating, heat sensitivity, weight loss, and enlarged thyroid gland. Major causes include Graves' disease, benign thyroid tumors, excess thyroid replacement medication, and inflammation of the thyroid, among others.
Treatment for hyperthyroidism includes surgery, radiation to the thyroid gland, and antithyroid medications.