Hyperthyroidism in children is serious. Hyperthyroidism is caused by excessive secretion of thyroid hormones. Thyroid hormones affect the body’s material and energy metabolism, influence the heat production process, increase the body’s heat production and affect the body’s growth and development, and also affect the development of the nervous system. In children, who are at a critical stage of growth and development, hyperthyroidism can affect multiple systems throughout the body and produce a variety of symptoms. The severity of hyperthyroidism in children includes the following: a. Typical hyperthyroidism is characterized by high metabolic symptoms such as fear of heat, sweating, lethargy and increased stool frequency, which may lead to nutrient deficiency and affect the growth and development of children. Second, hyperthyroidism can easily lead to symptoms such as inattentiveness, high excitability and agitation, which can also affect children’s psychological stability and learning. Third, hyperthyroidism in children can also develop into hyperthyroid heart disease, leading to various heart arrhythmias and even heart enlargement and heart failure. 4. Hyperthyroidism in children can also cause liver damage and leukopenia. Children with hyperthyroidism can also suffer from thyroid crisis due to infection, which can be life-threatening.