[Arousal disorders].

Altered states of consciousness are a common reason for visits to the emergency room and admission to intensive care unit. Management of unconscious patient can be difficult because the potential causes of an altered mental status are considerable and the time for diagnosis and effective intervention is short. First, the patient must airway, breathing, and circulation protected. It is important to obtain carefully taken history from eyewitnesses and to perform a general complete examination particularly neurologic focusing on pupillary responses, eye movements, and motor responses. Technical investigations like CT-scan and laboratory tests should make part of a careful diagnostic plan. The prognosis for recovery depends greatly on the underlying etiology as well as its optimal treatment, which seeks to preserve neurologic function and maximize the potential for recovery by reversing the primary cause of brain injury, if known, and preventing secondary brain injury from anoxia, ischemia, hypoglycemia, cerebral edema, and electrolyte disturbances.