Coma is a state of deep unconsciousness. The word comes from the Greek word koma, meaning deep sleep. People in comas ordinarily cannot be aroused by stimulants such as spirits of ammonia, light slapping, or a pinprick. Causes may include drug overdoses, seizures, head injuries, tumors, strokes, diabetes, and diseases of the liver or kidneys. Doctors treat coma according to its cause. For example, if it is caused by a drug, the doctor gives an antidote.
See also Persistent vegetative state .
