People often confuse coma as being necessary for brain injury to occur. This is far from the facts or truth. However coma usually confirms that brain injury has, in all probability, robbed the individual of cognition or motor function. Only rarely does one recover completely from coma.
I thought a refresher on what Coma and Glasgow Coma Scale are would be helpful.
A coma, or being comatose, is a deep state of unconsciousness - longer-term comatose patients
may be reclassified as being in a permanent vegetative state. Recall Terry Schiavo. The patient cannot be awakened and does not respond to pain, light or sound in a normal way - the person in coma cannot react with the surrounding environment. A person in a coma does not take voluntary actions and does not have sleep-wake cycles.
The inability to waken differentiates coma from sleep. Levels of unconsciousness and unresponsiveness vary, depending on how much of the brain is functioning. Neurological Experts and family often argue about whether the comatose patient can hear voices or perceive events or the presence of people.
Coma may occur for various reasons, such as intoxication, CNS (central nervous system) diseases, a traumatic injury, and hypoxia (oxygen deprivation). Coma can be induced deliberately with pharmaceutical agents - perhaps in order to protect the patient from intense pain during a healing process, or to preserve higher brain function following another form of brain trauma.
Comas generally do not last for more than a few weeks. A patient whose state does not change after an extended period is often reclassified as being in a persistent vegetative state. Unfortunately, those in a persistent vegetative state for over twelve months rarely wake up.
Another condition is known as "Locked-In Syndrome." Locked-in syndrome is a rare neurological disorder characterized by complete paralysis of voluntary muscles in all parts of the body except for those that control eye movement. It may result from traumatic brain injury, diseases of the circulatory system, diseases that destroy the myelin sheath surrounding nerve cells, or medication overdose. Individuals with locked-in syndrome are conscious and can think and reason, but are unable to speak or move. The disorder leaves individuals completely mute and paralyzed. Communication may be possible with blinking eye movements
A book and movie called "The Butterfly and Diving Bell" was written by Jean-Dominique Bauby who could only move his eyelid. Through the help of an interpreter, he wrote the entire book, letter by letter, by moving his eyelid when the letter was identified.
What are the possible causes of a coma?
A coma can have several possible causes, including:
- Diabetes - if the blood sugar levels of the diabetes patient rise too much they will have hyperglycemia, the opposite is hypoglycemia (blood sugar levels are too low). Sustained periods of hyperglycemia or hypoglycemia can result in coma.
- Hypoxia (lack of oxygen) - a person who nearly drowned may not awaken because of a shortage of blood (which carries oxygen) to the brain. The same may occur to somebody who is resuscitated after a heart attack.
- Infections - those which cause inflammation of the brain, spinal cord or tissues surrounded the brain can result in coma if symptoms are severe enough. Examples include encephalitis or meningitis.
- Stroke - a condition where a blood clot or ruptured artery or blood vessel interrupts blood flow to an area of the brain. A lack of oxygen and glucose (sugar) flowing to the brain leads to the death of brain cells and brain damage, often resulting in impairment in speech, movement, and memory - and sometimes coma.
- Toxins and drug overdoses - exposure to carbon monoxide can result in brain damage and coma, as can some drug overdoses.
- Traumatic brain injuries - these include injuries from vehicle accidents and violent attacks. They are the most common cause of comas.
Diagnostic Tools
Lumbar puncture (spinal tap) - this can determine whether there is an infection. The doctor inserts a needle into the patient's spinal canal, measures pressure and extracts fluid. Ruling out meningitis usually utilizes spinal tap.
Imaging scans of the brain - these will help determine whether there is any brain injury/damage, and where. Examples include:
- CT (computed tomography) scan - also known as a CAT (Computer Axial Tomography) scan. It is a medical imaging method that employs tomography. Tomography is the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram). The medical device is called a CTG scanner; it is a large machine and uses X-rays. It used to be called an EMI scan, because it was developed by the company EMI.
- MRI (magnetic resonance imaging) scan - an MRI machine uses a magnetic field and radio waves to create detailed images of the body, which in this case would be the brain. Most MRI machines look like a long tube, with a large magnet present in the circular area. When beginning the process of taking an MRI, the patient is laid down on a table. Then depending on where the MRI needs to be taken, the technician slides a coil to the specific area being imaged. The coil is the part of the machine that receives the MR signal. MRI scans are good for examining the brainstem and deep brain structures. The doctor may inject a special dye which shows up on the scans and distinguishes healthy tissue from damaged tissue.
- EEG (electroencephalography) - the device measures the electrical activity within the brain. Electrodes are placed on the patient's scalp; they pick up electrical impulses that occur in the brain. These impulses are recorded on the EEG device. An EEG can tell whether the patient is having non-convulsive seizures.
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- PET (Positron Emission Tomography) - a nuclear medicine imaging technique which produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Images of tracer concentration in 3-dimensional space within the body are then reconstructed by computer analysis.
Glasgow Coma Scale (GCS)
This scale is very useful for determining conciousness in severe cases. Unfortunately it is fequently misused in cases of mild and moderate traumatic brain. For instance, Mild Traumatic Brain Injury, which many times has devasting consequences, is defined by the same value on GCS as for a completely normal individual. Hence those with incentive to discredit the reality of brain injury point to the "normal" GCS.
The GCS scores patients according to verbal responses, motor responses (physical reflexes), and how easily they can open their eyes.
- Eyes - Glasgow Coma Scale
Score of 1 - does not open eyes.
Score of 2 - opens eyes in response to painful stimuli (when given pain).
Score of 3 - opens eyes in response to voice.
Score of 4 - opens eyes spontaneously.
- Verbal - Glasgow Coma Scale
Score of 1 - makes no sound.
Score of 2 - incomprehensible sounds (mumbles).
Score of 3 - utters inappropriate words.
Score of 4 - confused, disorientated.
Score of 5 - oriented, chats normally.
- Motor (physical reflexes) - Glasgow Coma Scale
Score of 1 - makes no movements.
Score of 2 - extension to painful stimuli (straightens limb when given pain).
Score of 3 - abnormal flexion to painful stimuli (moves in a strange way when given pain).
Score of 4 - flexion/withdrawal to painful stimuli (moves away when given pain).
Score of 5 - localizes painful stimuli (can pinpoint where pain is).
Score of 6 - obeys commands.
- Brain injury will be classified in the Glasgow Coma Scale as:
Coma = a score of 8 or less.
Moderate = a score of 9 to 12.
Minor = a score of 13 or more.
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