A high TSH and low T4 indicates that the patient should be suffering from hypothyroidism. Hypothyroidism is a systemic disease caused by insufficient synthesis or weakened physiological function of thyroid hormones, when the systemic metabolism is lowered. When thyroxine is lowered, the hypothalamus-pituitary-thyroid axis stimulates the secretion of thyrotropin to increase, so a high TSH and a low T4 is a sign of hypothyroidism. Hypothyroidism occurs in women, in people with certain familial or autoimmune diseases. Therefore, it is important to check for peroxidase antibodies and thyroglobulin antibodies to see if it is caused by autoimmune thyroiditis. Treatment should be supplemented with thyroxine replacement therapy, and if the patient is in a remote mountainous area or far from the sea, iodine supplementation or eating more iodine-rich food is recommended during treatment.