Hyperthyroidism is an overproduction of thyroid hormone. Signs and symptoms of hyperthyroidism include palpitations, anxiety, tremulousness, insomnia, diarrhoea, tachycardia, heat intolerance, and weight loss. The most common cause of hyperthyroidism is Graves disease, an autoimmune disorder resulting from an activating autoantibody against the TSH receptor that causes excess production of T3 and T4 (thyroid hormones). Other causes of hyperthyroidism include exogenous intake of thyroid hormone, thyroiditis, and thyroid nodules. Laboratory studies obtained in the workup of hyperthyroidism due to autoimmune causes usually evidence suppressed TSH levels with elevated thyroid hormone levels.
Hyperthyroidism can be treated with a number of pharmacological therapies, some aimed at controling symptoms and others aimed at treating the underlying disease. Beta-blockers (e.g. propranolol) are used to improve symptoms of anxiety, tremulousness, palpitations,...