A coma is a profound or deep state of unconsciousness. The affected individual is alive but is not able to react or respond to life around him. Coma may occur as an expected progression or complication of an underlying illness, or as a result of an event such as head injury. Muscle jerking may occur, but those in a coma do not move on purpose, even in response to pain.
How does it occur?
Coma occurs as a result of an illness or injury that causes serious damage to the central nervous system (CNS). The central nervous system is made up of the brain and spinal cord. Coma may result from:
accidents or blows to the head
bleeding within the brain
pressure on a part of the brain
drug or alcohol overdose
lack of oxygen, as may occur in cardiac arrest, severe lung disease, or carbon monoxide poisoning
severe imbalance of chemicals in the body
other conditions affecting the function of the CNS, such as a period of very low blood pressure during which the brain does not get enough blood flow.
What are the symptoms?
Before coma sets in there may be some warning signals. These include:
lack of energy
decline in the ability to think and reason
Other symptoms will depend on the underlying cause of the coma.
How is it diagnosed?
Coma is diagnosed by a physical exam and additional information from others about the events surrounding the onset of the coma. Some tests are needed to find out what caused the coma. A coma that came on suddenly suggests a different cause than one that came on slowly. The health care provider will also need information about the person's medical history and any medication he is taking. To help determine the cause of the coma, the health care provider may ask for tests that could include:
a brain scan, such as a CT (computed tomography) scan
a brain wave test, called an electroencephalogram (EEG)
a spinal tap, a procedure in which spinal fluid is withdrawn through a needle and examined.
Glasgow coma scale:
It provides a standardised method of assessing a comatose patient and eliminates the use of ambiguous and easily misinterpreted terms such as unconscious and semicomatose. Additional assessment data should include evaluation of the gag and corneal reflexes. In the absence of gag reflex, regurgitation and aspiration are potential problems.
How is it treated?
Treatment will depend on the cause of the coma. Some people who are in a very deep coma may need intensive care, including a ventilator to help them breathe, medications, and food and fluid given through the veins or through a feeding tube. Some people recover fully after a coma, some recover but have permanent brain damage, and some die without regaining consciousness. Others live on in a state in which they sleep and wake, but do not recover awareness or the ability to interact.