Overview

Coma is a state of prolonged unconsciousness that can be caused by a variety of problems — traumatic head injury, stroke, brain tumor, drug or alcohol intoxication, or even an underlying illness, such as diabetes or an infection.

Coma is a medical emergency. Swift action is needed to preserve life and brain function. Doctors normally order a series of blood tests and a brain scan to try to determine what's causing the coma so that proper treatment can begin.

A coma seldom lasts longer than several weeks. People who are unconscious for a longer time might transition to a persistent vegetative state or brain death.