L12: Aurosal Coma And Unconsciousness Flashcards
What is consciousness
Awareness of sleep and environment
What is arousal
Part of consciousness and it the level of consciousness i.e responding to predictable reflexes
Is arousal and awareness the same
No
What is awareness
The content of consciousness i.e to perceive to specific environmental stimuli to relate to yourself and the rest of the world
What can disorders of consciousness affect
Arousal
Awareness
What are the neural substrates of consciousness
The brainstem nuclei of reticular activating system
What does the reticular activating system switch on
The cortex
Where does the cortex send the information back to
Reticular activating system
Where does the frontal cortex send a signal to
Striatum
Where does the striatum send a signal to
Globus pallidus interna to inhibit it
When the stimulation of the striatum decreases what happens to the globus pallidus interna
Released which inhibits the reticular acitvating system
When the reticular acitvating system is inhibited what happens
Consciousness decreases and you fall into sleep
If pathological you go into coma
Therefore what is keeping is awake
The striatum inhibiting the globus pallidus interna
Therefore if there is an injury to the striatum what can we do to inhibit the globus pallidus interna and stimulate the cortex
Use inhibitor neurotransmitters that inhibit the globus pallidus interna
What is the cortex responsible for
Awareness
What is the brainstem responsible for
Arousal
What is brain stem death
Person has no brainstem function, permanent loss of consciousness and capacity to breathe but heart is beating
What is coma
Failure of arousal and awareness
What can coma be assessed with
Glasgow coma scale
What score indicates coma
Less than 8
What is vegetative state
When the brainstem is maintained due to preserved arousal but complete absence of self and environment awareness
What is minimally conscious state
Cognitive mediated behaviour occurs inconsistently but it reproducible that is different from a reflex and there is arousal
What is the presentation of minimally conscious state
Person can follow a simple command
Gestural or verbal yes or no
Purposeful behaviour such as moving eyes with a mirror
What are the 2 levels of minimal conscious state
With language
Without language
What is moving on from minimally conscious state characterised by
Functional communication of yes or no
Functional object use e.g brining comb to head
What is akinetic mutism
A subtype of minimally conscious state
What is akinetic mutism
Everything is reduced but then you suddenly give high intensity sensory stimulus and things change
Give an example of a high intensity stimulus in akinetic mutism
Giving a phone to their and they speak to someone meaningful
What is locked in syndrome
Arousal and awareness are preserved but motor outflow is blocked
What are the causes of locked in syndrome
Brain stem pathology
What are the 3 subtypes of locked in syndrome
Classical
Incomplete
Complete
How does classical locked in syndrome present
Upgaze
Blinking only with anarthria
Tetra paresis
Preserved consciousness
How does incomplete locked in syndrome present
Minimal movements in other limb with upgaze and blinking
What is complete locked in syndrome
No limb or eye movement but preserved consciousness
What is cognitive motor dissociation
Unconscious awareness detected by MRI and EEG
What can be seen on an MRI for someone who has cognitive motor dissociation
Reproducible brain repsonce as if a task is being carried out if you ask them to
In an hyper acute situation what scale do we use to asses
Glasgow coma scale
What does the Glasgow coma scale look for
Eye opening
Verbal response
Best motor response
What are the physical finding that we also assess for
Pupils
Motor functions
Autonomic features
If pupils are fixed and unresponsive what does this indicate
Brain stem damage
As intracranial pressure increases and brainstem becomes under pressure what do we get
A Cushing’s triad
What is the Cushing triad
Hypertension
Bradycardia
Respiratory irregularity
In a post acute assessment what do we establish
Diagnosis
Trajectory: are things changing over time
Prognosis
When does survival decrease
From traumatic injury to non traumatic
