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 (spatiotemporally
disorientated, 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 bihemispheric
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: endocraneal 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
