[Patients with alteration of consciousness in the emergency department].

A subject is conscious when he is awake and with an adequate awareness of him and the environment. The term alteration of consciousness requires specification as to whether it defines alteration of arousal--when the patient might be confused, in a stupor or in some degree of coma (light, deep)--or alteration of awareness--that is, confused (spatio-temporally disoriented, with difficulty in maintaining his attention), with or without delirious ideation. The coma, in the strict sense, originates from structural (neurological) or functional (metabolic) dysfunction of the ascending reticular activator system, but it is accepted that it can derive also from diffuse bi-hemispheric cortical-subcortical damage. In the emergency department the starting point is the triad of situations that requires immediate treatment applying the normal protocol (ABC); next, pathologies involving risk to life, which might cause cerebral hypoxia, are ruled out: diminished cardiac output, shock and respiratory failure. Subsequently, a neurological evaluation is made, bearing in mind two situations of potential gravity: endocranial hypertension and diseases that might cause respiratory failure due to muscular fatigue. Neurological exploration will specify the respiratory, pupil and ocular patterns and motor responses. The depth of the coma is established through scales; a simplification of Jouvet's scale is proposed. The etiological diagnosis will on occasion require image tests and lumbar puncture.