In broad terms this refers to conditions disturbing the arousal function of the brain. This is tested by evaluating patients response to pain by evaluating speech, eye opening and limb movement. This method is referred to as the Glasgow Coma Scale (GCS). When there is no speech, eye opening or limb movement in response to pain the patient is in a coma.
Impaired consciousness can be caused by intracranial (conditions in the skull) or extracranial (outside the skull) causes.
Common intracranial causes are: Tumours, trauma, stroke, infections
Common extracranial causes are: Liver or kidney failure, heart or lung failure and drugs.
Treatment is to support the patient by putting them on life support and treat the offending cause.