Hypertonic dehydration usually has the following causes: 1. Significantly insufficient intake of water, such as when the patient is in a coma, trauma, or unable to swallow due to esophageal or gastrointestinal diseases, and the patient is unable to eat, or insufficient water is given in critical condition, all of which will cause the patient to lose more water than sodium, which will increase the plasma osmolality. 2. Excessive loss of water and not replenished in time, such as when the patient is in hyperthermia, massive sweating, These conditions can occur during large burns, tracheotomy, and thoracoabdominal surgery.3. Patients with endocrine metabolic diseases, such as hyperthyroidism or diabetes mellitus in hyperosmolar coma, can suffer from hypertonic dehydration.