A temporary or prolonged state in which a person is unable to remain awake, aware, and responsive to their surroundings.
Consciousness depends on coordinated function of the brain and adequate blood flow, oxygen, and metabolic support. Loss of consciousness can occur for many reasons, including fainting, seizures, head injury, severe low blood pressure, abnormal heart rhythms, intoxication, or serious illness.
The duration and circumstances surrounding the event are important in determining its cause and medical significance.
QUICK FACT
Loss of consciousness is not the same as sleep. A sleeping person can normally be awakened and responds appropriately to stimulation.
COMMONLY CONFUSED WITH
Fainting (syncope): a specific, usually brief loss of consciousness caused by temporary inadequate blood flow to the brain.
SEE ALSO
