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by Lukas R


Information about your environment is normally passed from the brainstem into the rest of the brain. This feedback allows a person to be aware of and react to the environment. A coma is caused by a breakdown in this system.
Brainstem and Cerebrum
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The system may be interrupted by:

Risk Factors

Risk factors for coma include:
  • Severe illness
  • Diabetes
  • Liver, kidney, or cardiovascular disease
  • Tendency to have blood clots
  • Exposure to poisonous substances (such as carbon dioxide)
  • Cancer and chemotherapy
Risk factors for brain injury include:
  • Age: 5 years or younger, 15-24 years old, and 75 years or older
  • Sex: male
  • Traveling in a vehicle at a high rate of speed or at night
  • Lack of sleep
  • A previous head injury


Since the patient cannot speak, the doctor will need to gather information from other sources. The doctor may need to speak to friends, family members, and people who witnessed the accident. This is important to help with diagnosis. The doctor will also need to know about the person’s medical history and any drug or alcohol use. It is important to provide honest information in order to help with treatment.
The doctor will test reflexes, listen to breathing, and examine the eyes. A physical exam will also be done including tests of the nervous system. In addition, the following tests may be done:
Clinical findings of comatose patients can be rated according to the Glasgow Coma Scale (GCS). This scale assesses three different functions: eye opening, motor response, and verbal response. Scores can range from 15 to 3. A lower score indicates less responsiveness. Scores are interpreted as follows:
  • 15-13—mild brain injury
  • 12-9—moderate brain injury
  • 8 or less—a severe brain injury


A coma is a medical emergency. Any unconscious person should be taken to the emergency room immediately.

Emergency Treatment

Doctors will work quickly to determine the cause of the coma. Further treatment will depend on the cause of the coma. Supportive care may include:
If a specific cause of the coma is suspected, supportive care may also include:
  • Glucose delivered through IV—in case low blood sugar is causing the coma
  • Naloxone—if a narcotics overdose is suspected
  • Thiamine (vitamin B1) may be given with glucose if alcoholism or malnutrition is suspected
In some cases, surgery may correct the cause of a coma.

Ongoing Treatment

If the coma persists after emergency care, ongoing care may be needed. Once the person is stabilized, treatment will focus on providing nutrition and preventing infections. The care staff will also work to prevent bedsores .


The following can help decrease your risk of coma:
  • Wear a seatbelt . Make sure infants and small children are securely fastened in a child safety seat.
  • Children aged 12 years and under should ride in the back seat of a vehicle.
  • Wear an appropriate helmet while biking, rollerblading, playing contact sports, skiing, snowboarding, and riding a motorcycle.
  • Wear athletic mouth guards while playing sports.
  • Do not abuse alcohol or drugs .
  • If you have diabetes, see your doctor regularly and take appropriate steps to regulate your blood sugar levels.
  • If you are ill or take medicine, see your doctor regularly for check-ups.


Brain Injury Association of America

Coma Recovery Association, Inc.



Brain Injury Association of Canada

Ontario Brain Injury Association



Berger, JR. Stupor and coma. In: Bradley WG, et al, eds. Neurology in Clinical Practice . 5th ed. Philadelphia, PA: Butterworth Heinemann Elsevier; 2008.

Braunwald E. Harrison's Principles of Internal Medicine . 15th ed. New York, NY: McGraw-Hill; 2001.

Coma. EBSCO DynaMed website. Available at: . Updated February 20, 2012. Accessed August 31, 2012.

Hall JB, Schmidt GA, Wood L. Principles of Critical Care . 3rd ed. New York, NY: McGraw-Hill; 2005: chap 67.


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