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Author: Cassie Wang


A Coma is a state of unconsciousness, in which a person is alive but unable to respond to their environment. It lasts longer than 1 hour and usually for days to a few weeks. Coma lasts rarely longer than 4 weeks since most patients will transit to a vegetative state or other. A coma is an emergency that requires immediate medical attention. 



Coma is caused by 1) damage in the reticular activating system in the cortex and brainstem that controls wakefulness and awareness and 2) diffuse cortical or white matter damage after axonal injury. To be more specific: 

  • Traumatic brain injury: car accidents and violent acts 

  • Strokes and tumours in the brain 

  • Lack of oxygen after drowning and resuscitation of heart attack  

  • Carbon dioxide poisoning 

  • Diabetes, hyperglycemia (high blood sugar level) or hypoglycemia (low blood sugar level)

  • Toxins 

  • Overdosing substance 

  • Seizures 



  • Closed eyes, pupil not responding to light

  • No response to touch and pain, except reflexes  

  • Irregular breathing 



  • Medical professionals will seek for patient’s medical history to check for previous signs and drug use 

  • Physical tests will be performed to see how responsive the individual is to external cues using Glasgow Coma Scale  

  • Blood tests will be used to determine blood counts, glucose level, substance use, infection and liver function. 

  • Neuroimaging techniques such as CT scans, MRI and EEG to locate internal injury, seizures or tumour in the brain. 



Patients in coma will be sent to ICU (Intensive Care Unit). The ABC (airway, breathing, circulation) will be taken care of. Oxygen is delivered through a ventilation machine. Glucose and antibiotics will be given to patients in case of diabetes and infection even before blood test results. Specific treatment is dependent on the known cause of coma. Healthy nutrition will also be provided to patients throughout the coma. 



The outcome of coma is related to the severity and location of brain damage. People may come out of coma with physical and psychological issues. Physiotherapy and other support are necessary. If it lasts longer than 1 year, patients will rarely be responsive again. 


Visit patients in coma 

  • Some people can still hear in a coma. So tell them who you are and share your daily life. Moreover, show your support and love. 

  • Senses like touch and smell will be beneficial to their recovery. Hold their hand, bring a bouquet of flowers, or play their favorite song. 



Bonovich, D. C. (2007). Coma. Critical Care Secrets, 381-384. doi:10.1016/b978-1-4160-3206-9.10059-x

Brazier, Y. (2017, November 20). Coma: Causes, diagnosis, treatment, and outlook. Retrieved from

Jacquelyn, C. (2019, November 1). Coma. Retrieved from

Laureys, S., Boly, M., Moonen, G., & Maquet, P. (2009). Coma. Encyclopedia of Neuroscience, 1133-1142. doi:10.1016/b978-008045046-9.01770-8

Mayo Clinic. (2020, November 20). Coma. Retrieved from

Medline Plus. (2021, March 23). Coma. Retrieved from

NHS. (n.d.). Coma. Retrieved from

WebMD. (n.d.). Coma: Types, Causes, Treatments, Prognosis. Retrieved from

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