Hyperthyroidism is caused by excessive production of thyroid hormones by the thyroid glands, resulting in thyrotoxicosis. The main causes include nodular goiter, diffuse goiter, and hyperfunctioning autonomic adenoma of the thyroid gland, and, less commonly, Hashimoto’s hyperthyroidism and tumors of the pituitary gland. When hyperthyroidism occurs, patients may experience increased excitability and hyper-metabolism, such as irritability, irritability, fear of heat, excessive sweating, hyperphagia, irritability, insomnia, increased stool frequency, increased heart rate, and muscle tremors. Generally, if a patient develops these hypermetabolic symptoms, he or she should immediately go to a hospital to receive a thyroid function level as well as an ultrasound examination of the thyroid gland. In hyperthyroidism, TSH levels are significantly lower and TT3, TT4, FT3 and FT4 levels are significantly higher. thyroid ultrasound can help detect nodules or diffuse enlargement of the thyroid gland, and can detect the presence of autonomic hyperfunctional adenomas and thyroid tumors. When hyperthyroidism occurs, treatment includes the use of antithyroid medications, iodine-131 therapy, and surgery.