昏迷是多种危重病人的症状之一。是意识障碍最严重阶段，也是病情危急的信号，常见于颅内疾病和颅外疾病。颅内疾病多见于脑血管意外、颅脑损伤和颅内感染或肿瘤。颅外疾病有缺氧、缺血、肝、肾衰竭，肺性脑病，糖尿病昏迷以及外源性中毒等。不论何种原因引起的昏迷，常示后果 Coma is one of the symptoms of many critically ill patients. Is the most serious stage of disturbance of consciousness, but also the critical condition of the signal, common in intracranial disease and extracranial disease. Intracranial disease more common in cerebrovascular accidents, brain injury and intracranial infection or tumor. Extracranial disease hypoxia, ischemia, liver and kidney failure, pulmonary encephalopathy, diabetic coma and exogenous poisoning. No matter what causes coma, often show the consequences