Hypoglycemia is defined as an intravenous glucose concentration of less than 2.8 mmol/L. Coma caused by hypoglycemia is called hypoglycemic coma. Hypoglycemic coma is the most common and important complication in the treatment of diabetes. Diabetic patients are prone to hypoglycemic coma, mainly in the following cases: 1, when diabetic patients with rapid decline in blood glucose, the brunt of the cerebral cortex is inhibited, hazy consciousness, orientation and identification ability loss, mental disorders and slurred speech. When subcortical inhibition produces restlessness, tachycardia and pupil dilation. When the midbrain is involved, paroxysmal convulsions occur, and soon fall into hypoglycemic coma; 2. Some patients, especially unstable and juvenile diabetic patients, or insulin overdose, hypoglycemic reaction is not easy to be relieved on their own, and present malignant hypoglycemic reaction symptoms. For example, acute psychosis or epileptic-like convulsions can rapidly enter a severe coma; 3. The more often hypoglycemia occurs, the more atypical the symptoms of hypoglycemia. Even in severe hypoglycemia there is no obvious manifestation of increased adrenaline secretion, and the psychiatric abnormal symptoms are very transient and can rapidly fall into a deep coma. Or when the disease is of long duration and there is vegetative neuropathy, the sympathetic nerves do not respond, and coma also occurs easily.