The common clinical manifestations of hyperthyroidism include: 1. Hypermetabolic syndrome, which is characterized by fear of heat, excessive sweating, panic attacks, hyperphagia, weight loss, irritability, hand tremors, etc. It may not be typical in the elderly. 2. Enlargement of the thyroid gland and thickening of the neck. 3. Some patients may have proptosis. The reason why 131 iodine can treat hyperthyroidism is that most of the 131 iodine accumulates in the thyroid gland after entering the body. During the decay of 131 iodine, beta rays are released, which have a range of only 2 mm in the thyroid gland. Therefore, 131 iodine treatment for hyperthyroidism has been described as “bloodless surgery”. Since most of the medication is absorbed by the thyroid gland and other organs are not affected, it does not cause a decrease in white blood cells and liver function damage. If the T3, T4 and Tsh are normal, it is considered to be cured and there is no need to take any more medication.