Hypothyroidism, known as hypothyroidism, is a systemic hypometabolic syndrome caused by various causes of hypothyroxinemia or thyroid hormone resistance. Causes of hypothyroidism include autoimmune damage, thyroid destruction, hypothalamic and pituitary lesions, etc. Patients may not have obvious symptoms in the early stage of the disease, and later have symptoms such as chilliness, weakness, and slowed heart rate. I. Causes 1. autoimmune damage: autoimmune thyroiditis, including Hashimoto’s thyroiditis, atrophic thyroiditis and postpartum thyroiditis, can reduce the synthesis and secretion of thyroid hormones, leading to hypothyroidism; 2. thyroid destruction: when performing thyroid surgery, such as subtotal thyroidectomy, the thyroid gland is destroyed, leading to hypothyroidism; 3. hypothalamic and pituitary lesions. This can lead to hypothyroidism due to reduced production and secretion of thyrotropin and thyrotropin-releasing hormone, such as external pituitary irradiation, pituitary macroadenoma, craniopharyngioma, etc.; 4. iodine overdose: iodine overdose can cause hypothyroidism in people with underlying thyroid disease, and can also induce and aggravate autoimmune thyroiditis; 5. anti-thyroid drugs: anti-thyroid drugs, such as lithium salts and thioureas, can inhibit The anti-thyroid drugs, such as lithium and thiourea, can inhibit the synthesis of thyroid hormones, leading to hypothyroidism. Symptoms of hypothyroidism are mainly based on reduced metabolic rate and decreased sympathetic excitability. Typical patients may experience chills, fatigue, drowsiness, poor memory, dry and rough skin, ginger skin on the palms of the hands and feet, thinning hair, and women may also experience menstrual disorders and infertility. In severe cases, mucinous edema coma may occur.