Consciousness and GCS

The Glasgow Coma Score is used to assess the level of consciousness of an individual. The maximum score an individual can get is 15/15. The minimum score is 3/15. A deceased individual will gain a 3/15. Just remember, no one can score less than 3!

GCS assess best motor response, best verbal response and best eye opening response.

Eyes - They are opening spontaneously scores 4/4 points Voice - The patient is using inappropriate words so scores 3/5 Motor- The patient is moving all four limbs on command so scores 6/6 4 + 3 + 6 = 13/15

This individual is clearly alert and fully orientated so is GCS 15/15. This was designed to test whether you know the individual categories maximum scores. Eyes scores a maximum of 4 Voice scores a maximum of 5 Motor scores a maximum of 6

"Less than 8, ventilate!" A patient with a GCS less than 8 is in danger of having airway and respiratory compromise so you must remember your ABCDE approach. An airway problem will kill this patient faster than hypoglycaemia or an intracranial haemorrhage. Another set of observations is again important but the airway issue takes precedence. Hopefully you understand why ultrasound results from 2 weeks ago is not immediately relevant in this situation.

Persistent vegetative state is when a person is awake (eyes are open and sleep-wake cycles are present), but awareness and meaningful responses are absent. The reticular formation has a major role in the sleep/wake cycle and remains intact but the connection with the cerebral cortex is non-functional in persistent vegetative state.

"Locked-in" syndrome is usually due to an infarct in ventral pons involving the corticobulbar and corticospinal tracts. Sensation, reticular formation and cortical function remains intact so the person is fully awake and aware. However, motor function is mostly absent, only vertical eye movements and eyelid elevation may be spared, hence the description "Locked in" as the individual is aware of everything but can only move their eyes vertically.

Eyes are spontaneously open so scores 4 points Verbal - there is some confusion as they keep repeating "Is it nearly tea time?" when in the stem it tells you it is shortly after 09:00. Therefore they score 4 Motor- This is not testable. With motor you score the patient based on the highest scoring response in any single limb. They cannot move any limb thus, motor is not testable in this individual. This would need to be explained as someone would wrongly assume a GCS of 8 out of 15 indicating a serious head injury.

This is a challenging question so please don't panic if this didn't make sense. Firstly let's think about what the GCS and stem are telling us. I hope you will agree this individual is quite unwell. They are only responsive to pain stimuli (trapezius squeeze) in all three areas. The motor symptoms are key here. This is an abnormal extension response to pain, also known as decerebrate posturing. Having a look at a cartoon of decerebrate posturing may help to make the description in the stem more clear. So now let's think what does decerebrate posturing mean? This indicates brain stem damage. These signs will be exhibited in people with lesions or compression in the midbrain or lesions in the cerebellum. You might be wondering why the pons isn't involved. A separate descending pathway called the pontine reticulospinal tract originates in the pons. It receives pain signals from the spinothalamic tract and initiates an extension response Thus the correct answers are midbrain and cerebellum.

Abnormal flexion response involves the adduction of the arm, internal rotation of the shoulder, pronation of the forearm and wrist flexion. This is known as decorticate posturing. (It may be helpful to look at a cartoon of decorticate posturing.) This indicates that there may be significant damage to the cerebral hemispheres, internal capsule and thalamus. In decorticate posturing the red nucleus is preserved. The red nucleus triggers flexion which overrides the extention signals from the pons so the arms flex upwards