1.Basic concept Consciousness is the ability of the central nervous system to respond meaningfully to stimuli in the internal and external environment, and the diminution or disappearance of this response ability is a different degree of consciousness disorder, and the severe cases are called coma. Any lesion involving the brainstem or bilateral cerebral cortex may cause disorders of consciousness and coma. Common causes are: (1) multifocal, diffuse, metabolic encephalopathy, such as abnormal metabolites, electrolyte disorders, abnormal osmotic pressure, nutrient deficiency, hypothermia or hypothermia, poisoning, trauma, etc.; (2) ischemic-hypoxic encephalopathy such as myocardial infarction, cardiac arrhythmia, visceral hemorrhage, shock, tumor, poisoning, respiratory muscle anesthesia, etc.; (3) diffuse central nervous system diseases, such as inflammation, (3) diffuse CNS diseases, such as inflammation, vascular disease, tumor, poisoning, trauma, demyelinating disease, etc.; (4) sub-cerebellar lesions, such as brainstem or cerebellar infarction, hemorrhage, inflammation, tumor, etc. (3) Clinical manifestations (1) drowsiness: a pathological sleepiness, the patient falls into a continuous sleep state, can be awakened, and can correctly answer and make various responses, but when the stimulus is removed soon after falling back to sleep. (2) Blurred consciousness: manifested as maintaining simple mental activities, but the ability to orient to time, place and people is impaired. (2) Lethargy: It is close to unconsciousness, in a state of sleep, not easy to wake up, or can be woken up under strong stimulation, but soon fall back to sleep. When waking up, the answer is vague or non-responsive. Coma: The manifestation is a continuous interruption of consciousness or complete loss. Various reflexes are weakened or disappear as the impairment of consciousness increases. According to its degree, it can be classified as mild coma, moderate coma, and severe coma. Delirium: It is a state of acute dysfunction of the higher nerve centers mainly due to increased excitation, manifested as blurred consciousness, disorientation, sensory confusion, agitation, and garbled speech. 4.Concomitant symptoms may be accompanied by fever, slow breathing, dilated or narrow pupils, bradycardia, hypertension or hypotension, skin and mucous membrane hemorrhage, meningeal irritation signs, paralysis, etc. 5. Consultation points During the consultation, attention should be paid to the urgency of the onset of the disease, the progression of the disease, concomitant symptoms and the presence of previous chronic diseases of the heart, liver, kidney, lung, etc., and the history of medication.