Coma

Not to be confused with Comma.
For other uses, see Coma (disambiguation) and Comas (disambiguation).
"Comatose" redirects here. For other uses, see Comatose (disambiguation).
Coma
Image of a comatose man unresponsive to stimuli
SpecialtyNeurology, psychiatry
SymptomsUnconsciousness
ComplicationsPersistent vegetative state, death
DurationCan vary from a few days to several years

A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions.[1] The person may experience respiratory and circulatory problems due to the body's inability to maintain normal bodily functions. People in a coma often require extensive medical care to maintain their health and prevent complications such as pneumonia or blood clots.[2] Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move.[3][4] Comas can be the result of natural causes, or can be medically induced.[5]

Clinically, a coma can be defined as the consistent inability to follow a one-step command.[6][7] It can also be defined as having a score of 8 or less on the Glasgow Coma Scale (GCS) for at least 6 hours.[8] For a patient to maintain consciousness, the components of wakefulness and awareness must be maintained. Wakefulness is a quantitative assessment of the degree of consciousness, whereas awareness is a qualitative assessment of the functions mediated by the cortex, including cognitive abilities such as attention, sensory perception, explicit memory, language, the execution of tasks, temporal and spatial orientation and reality judgment.[3][9] Neurologically, consciousness is maintained by the activation of the cerebral cortex—the gray matter that forms the brain's outermost layer—and by the reticular activating system (RAS), a structure in the brainstem.[10][11]

  1. ^ Weyhenmyeye, James A.; Eve A. Gallman (2007). Rapid Review Neuroscience 1st Ed. Mosby Elsevier. pp. 177–9. ISBN 978-0-323-02261-3.
  2. ^ Huff, J. Stephen; Tadi, Prasanna (2022), "Coma", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 28613473, retrieved 2023-03-19
  3. ^ a b Bordini, A.L.; Luiz, T.F.; Fernandes, M.; Arruda, W. O.; Teive, H. A. (2010). "Coma scales: a historical review". Arquivos de Neuro-Psiquiatria. 68 (6): 930–937. doi:10.1590/S0004-282X2010000600019. PMID 21243255.
  4. ^ Cooksley, Tim; Holland, Mark (2017-02-01). "The management of coma". Medicine. 45 (2): 115–119. doi:10.1016/j.mpmed.2016.12.001. ISSN 1357-3039.
  5. ^ Marc Lallanilla (2013-09-06). "What Is a Medically Induced Coma?". livescience.com. Retrieved 2022-04-23.
  6. ^ "The Glasgow structured approach to assessment of the Glasgow Coma Scale". www.glasgowcomascale.org. Retrieved 2019-03-06.
  7. ^ "Coma - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-04-28.
  8. ^ "Glasgow Coma Scale - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-04-23.
  9. ^ Laureys; Boly; Moonen; Maquet (2009). "Coma" (PDF). Encyclopedia of Neuroscience. 2: 1133–1142. doi:10.1016/B978-008045046-9.01770-8. ISBN 9780080450469. Archived (PDF) from the original on 2014-10-20.
  10. ^ Hannaman, Robert A. (2005). MedStudy Internal Medicine Review Core Curriculum: Neurology 11th Ed. MedStudy. pp. (11–1) to (11–2). ISBN 1-932703-01-2.
  11. ^ "Persistent vegetative state: A medical minefield". New Scientist: 40–3. July 7, 2007. See diagram Archived 2017-08-26 at the Wayback Machine.