Coma is a state of prolonged unconsciousness that can be caused by a variety of problems — traumatic head injury, stroke, brain tumor, drug or alcohol intoxication, or even an underlying illness, such as diabetes or an infection.
Coma is a medical emergency. Swift action is needed to preserve life and brain function. Doctors normally order a battery of blood tests and a brain CT scan to try to determine what's causing the coma so that proper treatment can begin.
Comas seldom last longer than several weeks. People who are unconscious for a longer period of time may transition to a persistent vegetative state. Depending on the cause of coma, people who are in a persistent vegetative state for more than one year are extremely unlikely to awaken.
The signs and symptoms of coma commonly include:
When to see a doctor
Many types of problems can cause coma. Some examples are:
Although many people gradually recover from coma, others enter a vegetative state or die. Some people who recover from a coma may have major or minor disabilities.
Complications may develop during coma, including pressure sores, bladder infections and other problems.
Preparing for your appointment
Coma is an emergency medical condition. If you are with a person who develops signs and symptoms of coma, call 911 or your local emergency number immediately.
When you arrive at the hospital, emergency room staff will need as much information as possible from family and friends about what happened to the affected person before the coma. On the way to the hospital, you may be asked the following questions:
Tests and diagnosis
Because people in coma can't express themselves, doctors must rely on physical clues and information provided by families and friends. Be prepared to provide information about the affected person, including:
To determine the affected person's level of consciousness, doctors may speak loudly or press on the angle of the jaw or nail bed. Doctors will watch for signs of arousal, such as vocal noises, eyes opening or movement.
Doctors will test reflexive eye movements. These tests can help determine the cause of coma and the location of brain damage.
Doctors may also squirt ice-cold or warm water into the affected person's ear canals and observe eye reactions.
A spinal tap (lumbar puncture) can check for signs of infections in the nervous system. During a spinal tap, a doctor or specialist inserts a needle into the spinal canal and collects a small amount of fluid for analysis.
Treatments and drugs
Coma is a medical emergency. Doctors will first check the affected person's airway and help maintain breathing (respiration) and circulation. Doctors may give breathing assistance, blood transfusions and other supportive care.
Emergency personnel may administer glucose or antibiotics intravenously, even before blood test results return, in case of diabetic shock or an infection affecting the brain.
Treatment varies, depending on the cause of coma. A procedure or medications to relieve pressure on the brain due to brain swelling may be needed. If the coma is the result of drug overdose, doctors will give medications to treat the condition. If the coma is due to seizures, doctors will give medications to control seizures.
Other treatments may focus on medications or therapies to address an underlying disease, such as diabetes or liver disease.
Sometimes the cause of coma can be completely reversed and the affected person will regain normal function. But if the affected person has suffered severe brain damage, he or she may sustain permanent disabilities or may never regain consciousness. The person may enter a persistent vegetative state or brain death.
Last Updated: 2012-10-12
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