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What is a Coma?

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In 2005, the legal case of Terri Schiavo, a Florida woman who had become comatose after suffering massive brain damage following full cardiac arrest in 1990, caught the attention of the world. The highly publicized legal challenges surrounding the case centered on patients’ rights, but the media attention it drew also started a public conversation about what it means to be in a state of coma.

A coma, sometimes called a persistent vegetative state, is a profound or deep state of unconsciousness. A person who is in a state of coma is alive, but unable to move or respond to his or her environment.

He or she loses their thinking abilities but may retain non-thinking body functions, such as breathing and circulation. He or she may move spontaneously, his or her eyes may open in response to external stimuli, or grimace, cry or laugh.

Some individuals in a persistent vegetative state may appear normal, although they are unable to speak or respond to commands, according to the National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health.

The body doesn’t just decide to go into a state of coma. It typically occurs because of some traumatic assault — an underlying medical condition, drug overdose, or as a result to an injury, such as head trauma. Sometimes doctors induce a coma, such as with Arizona Congresswoman Gabrielle Giffords, who was shot in the head in 2011 during an alleged assassination attempt.

A medically induced coma effectively shuts down brain function and gives the brain time to heal without having to expend energy to perform cognitive tasks. This helps reduce swelling and protects the injured part of the brain most at risk when no other treatment has worked.

It's important to note a medically induced coma is not the same thing as sedation. A medically induced coma is a very deep unconscious state, whereas sedation, as used in surgery or in other medical procedures to keep a patient comfortable, is a semi-conscious state with minimal side effects.

Some underlying medical conditions can cause a person to become comatose. For example, a person with diabetes may suffer a diabetic coma from dangerously high ketones building up in the bloodstream. Ketones are a type of acid that helps metabolize fats rather than sugars for energy.

Myxedema coma is a relatively rare, but life-threatening complication of hypothyroidism seen most frequently in the elderly and in female patients. It occurs from a long-lasting episode of very low thyroid hormone levels in the blood.

Comas rarely last more than two to four weeks, but some people can remain in a persistent vegetative state for years — even decades. Recovery usually occurs gradually, with some acquiring more and more ability to respond.

The outcomes for coma and persistent vegetative state however, depend on the cause, severity and site of neurological damage. Some individuals never progress beyond the most basic responses, while others recover full awareness.

The Glasgow Coma Scale is a tool used by medical professionals to objectively determine the degree to which a person is comatose or conscious. The tool is based on a 15-point scale with higher scores indicating higher levels of consciousness. It is not unusual for the scale to be used multiple times during a patient’s comatose or persistent vegetative state.

Lynette Summerill, an award-winning writer and scuba enthusiast lives in San Diego, CA with her husband and two canine kids. In addition to writing about cancer-related issues for EmpowHER, her work has been seen in newspapers and magazines around the world.


The American Diabetes Association. has more information about diabetic coma and living with diabetes. Web 7 Sept. 2011. http://www.diabetes.org/living-with-diabetes

American Association of Anesthesiologists. Induced Coma vs. Sedation. Web 7 Sept. 2011.

National Institute of Neurological Disorders and Stroke. Coma Information Page has more information on coma treatments, outcomes and research. Web 7 Sept. 2011.

Brain and Spinal Cord.org. Glasgow Coma Scale. Web 7 Sept. 2011. http://www.brainandspinalcord.org/recovery-traumatic-brain-injury/glasgow-coma-scale.html

CBS News. Schiavo Politics.Up Close. March 25, 2005. Web 7 Sept. 2011. http://www.cbsnews.com/stories/2005/03/25/opinion/lynch/main683233.shtml

Reviewed September 8, 2011
by Michele Blacksberg R.N.
Edited by Jody Smith

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We value and respect our HERWriters' experiences, but everyone is different. Many of our writers are speaking from personal experience, and what's worked for them may not work for you. Their articles are not a substitute for medical advice, although we hope you can gain knowledge from their insight.


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