The clinical manifestations of hypothyroidism are as follows: First, general symptoms and signs, pallor, chill, weakness, indifferent expression, unresponsiveness, weight gain, enlarged nose, thick lips and tongue, mucous edema of the face and even the whole body. Second, the skin and subcutaneous tissue, waxy or pale skin, less sweating, dry skin, flaking, lack of elasticity, may have withered hair, hair loss, brittle and thickened nails. Third, the nervous system, often appear intelligence, memory, attention, comprehension and calculating power, serious cases can appear mental retardation, elderly patients in combination with cerebrovascular pathology, more likely to appear dementia, hypothyroidism in adults, patients often have hearing loss, juvenile hypothyroid patients, can appear neurological deafness. Fourth, the circulatory system, can appear bradycardia, weak heart sound, small pulse pressure, heart enlargement, pericardial effusion and myocardial hypertrophy, etc., serum cholesterol level is increased, the duration of the disease can have an increased risk of coronary heart disease. Fifth, the digestive system, because the gastrointestinal tract peristaltic function is reduced, so there can be loss of appetite, abdominal distension and constipation. Sixth, the respiratory system, respiratory symptoms are relatively rare, severe hypothyroidism patients can develop respiratory dysfunction, carbon dioxide paralysis. Seventh, the hematological system, about 25% of patients can develop varying degrees of anemia, mostly orthocytic, orthopoietic or microcytic, hypochromic anemia, mainly due to impaired absorption of iron and vitamin B12 and lack of hematopoietic material. Eighth, the urinary system, there can be reduced glomerular filtration rate, difficulty in urination, resulting in water and sodium retention, and excessive water consumption can lead to water intoxication. Ninth, the reproductive system, sexual hypogonadism is more common, men can appear impotence, women can appear excessive menstruation, prolonged periods and infertility.