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By Mayo Clinic staffMany types of problems can cause a coma. Some examples are:
- Traumatic brain injuries. Brain injuries that result from traffic collisions or acts of violence are the most common cause of comas.
- Stroke. Acute loss of blood flow to the brain followed by swelling or no blood flow to a major part of the brainstem can result in a coma.
- Diabetes. Blood sugar levels that get too high (hyperglycemia) and stay too high or get too low (hypoglycemia) and stay too low can cause coma.
- Lack of oxygen. People who have escaped drowning or been resuscitated after a heart attack may not awaken due to lack of blood flow and oxygen to the brain.
- Infections. Encephalitis and meningitis are infections that cause inflammation of the brain, spinal cord or the tissues that surround the brain. Severe cases of either encephalitis or meningitis can result in a coma.
- Toxins. Exposure to toxins, such as carbon monoxide or drug overdoses, can cause brain damage and coma.