Coma and Glasgow Coma scale

Most of the non medical people use word coma to describe a patient who is unconscious. But for a medical professional word "coma" is very specific because the impairment of arousal can vary from drowsiness ( sleepiness) to non-responding to any stimulus like sound or pain. Coma is the severest impairment of arousal, and is defined as the inability to obey commands, speak, or open  the eyes to pain.

One should learn the GCS scale to better understand the different levels of impairment of conscious level and to avoid descrepencies in describing the daily condition of the patient by different medical professionals and nurses.
Teasdale and Jennet,  in year 1875,  proposed a scale known as GCS ( Glasgow Coma Scale). Three types of stimulus and response to the patient to these three stimuli is described.
First is EYE OPENING
If patient opens his eyes spontaneously , i.e., like a normal person without any problem , then 4 point is mentioned.
Next situation is that patient is drowsy or feeling sleepy and is having closed eyes. The sleepy patient if opens eyes on sound then 3 point is given.
If patient eyes are closed and he opens eyes only when painful stimulus is given the, only 2 points is given.
And patient does not open eyes even on a painful stimulus then only 1 point is given so the lowest score of eye opening is 1.

E  4   spontaneous eye opening
E  3   opening eyes to speech
E  2   opening eyes to pain
E  1   None


Then  patient's verbal response is examined ( V stands for verbal response)


 V   5         Person is oriented 
                 (aware about what is happening around, Person is oriented to place, person and time )
 
 V    4        Confused or disoriented  

 V    3       speaking inappropriate words 
                                      ( Not producing sentences )

 V    2       producing incomprehensible words 
                                       ( Not producing word i.e. only some sound is produced by the patient) 

 V    1      None ( No verbal output means patient is not speaking and even not producing any sound)


Patient's Motor response is assessed

M      6      Obeys
          (Best motor resonpse is  M6 when patients moves limbs themselves and obey the command to move hand and feet whenever asked to do so)

M     5    patient localizes pain 
           ( when patient is pinched he tries to remove your fingers) 

M    4    Withdraws to pain
            ( here when patient is pinched feels pain and tries to withdraw from the pain)

M    3    Flexion to pain ( decorticate)
             ( in medical terminology it is known as decorticate posture , i.e., posture seen in an animal when the central nervous system is cut just below the level of cerebral cortex. Like in an experient by Sherrington, father of modern neurophysiology, when the brain of a cat was cut just  above the midbrain or brain stem, animal,s upper limbs were flexed and lower limbs were extended. This abnormal posture is known as DECORTICATE POSTURE)

M    2   Extensor ( decerebrate )
               ( extensor response to a painful stimulus is a very bad neurological sign. When a patient is pinched his both upper and lower limbs are extended)

M    1  No response to the painful stimulus


The best responses of the patient are added . So, the maximum GCS score is 15 and minimum is 3.

 
Glasgow coma scale score of equal or less than 8 is a generally accepted operational definition of coma.
It can result from dysfunction of brain stem, diencephalon or lesions of both cerebral hemispheres.This may be due to neoplastic lesions, electrolyte imbalance, metablic or endocrine problems, vascular lesions, infections, trauma or nutritional reasons.

GCS is an important method of describing patient's neurological condition but blood pressure, pulse rate,  respiratory rate, response of the pupils of  eye to light, paralysis of the limbs are other important parts of the  complete neurological assessment.