A coma is a deep state of unconsciousness. An individual in a coma is alive but unable to move or respond to his or her environment. Coma may occur as a complication of an underlying illness, or as a result of injuries, such as brain injury.
A coma rarely lasts more than 2 to 4 weeks. The outcome for coma depends on the cause, severity, and site of the damage. People may come out of a coma with physical, intellectual, and psychological problems. Some people may remain in a coma for years or even decades. For those people, the most common cause of death is infection, such as pneumonia.
NIH: National Institute of Neurological Disorders and Stroke
- What Is the Glasgow Coma Scale? (Brainline)
- Cerebral Hypoxia (National Institute of Neurological Disorders and Stroke) - Short Summary Available in Spanish
- JAMA Patient Page: Brain Death (American Medical Association) - PDF Available in Spanish
- Locked-In Syndrome (National Institute of Neurological Disorders and Stroke) - Short Summary
- Traumatic Brain Injury: Hope through Research (National Institute of Neurological Disorders and Stroke) Available in Spanish
- Diabetic Coma (Mayo Foundation for Medical Education and Research)
Journal ArticlesReferences and abstracts from MEDLINE/PubMed (National Library of Medicine)
Find an Expert
- American Academy of Neurology
- Find a Neurologist (American Academy of Neurology)
- National Institute of Neurological Disorders and Stroke Available in Spanish
- What Is a Coma? (Nemours Foundation)