A coma is a deep state of unconsciousness in which individuals do not consciously respond to stimuli in their environment. Coma can result from injury such as head trauma, or an underlying illness such as an infection or tumor, or toxins that enter the body.
Patients in a coma are unable to think consciously and lack awareness of their surroundings, but they do retain basic life support functions, such as breathing and circulation. A person in a coma may look healthy and appear as if they are sleeping, but they are unable to respond to people and things around them. A patient in a coma may exhibit some movement such as eye opening or grimacing in response to the environment; however, the patient does not have control or awareness of these movements.
A long-term coma is often referred to as a persistent vegetative state. This can last for years, depending on the medical circumstances and the cause.
In general, a coma is temporary, rarely lasting more than two to four weeks. After emerging from a coma, the prognosis is varied. Many people can recover fully, some require lifelong physical and occupational therapy, while others may recover only basic functions.
Medically Reviewed by a Doctor on 10/1/2015
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