Coma Flashcards
Define coma
state of unresponsiveness in which the patient lies with eyes closed and cannot be aroused to respond appropriately to stimuli even with vigorous stimulation
What is the difference between arousal and awareness?
consciousness is a combination of these two processes
Awareness= content of consciousness= cerebral cortex
arousal= level of consciousness = brain stem+diaencephalon
What are the levels of arousal?
alert
obtunded= reduced alertness, aroused with minimal stimulation
Stupor= reduced alertness, aroused with vigorous stimulation
Coma= eyes remain closed, no goal directed movements, even with painful stimulation
what is the arousal/awareness in vegetative state?
high arousal, low awareness
what lesions cause coma?
to produces stupor or coma in humans, a disorder must damage or depress the function of either extensive areas of both cerebral hemispheres or the ascending arousal system, including the paramedian region of the upper brainstem or the diencephalon on both sides of the brain
What functions are lost in locked in syndrome?
Quadraparesis (CST)
loss of lateral gaze (PPRF, CN VI)
facial paresis (CN VII)
anarthria (CN VII , X)
What functions are preserved in locked in syndrome?
awareness
vertical eye movements
vision
What is Kernohan’s notch?
Right uncal herniation causes:
Right CNIII palsy
Depressed level of consciousness
AND
left hemiparesis: herniated uncus presses on right cerebral peduncle
right hemiparesis: left cerebral peduncle pressed against left tentorial notch= kernohan’s notch
PCA obstruction= cortical blindness
pupils are asymmetrical, fixed, dilated. cause?
CNIII, uncall (parasymp. fibres to pupillary constrictor are destroyed
pupils are midposition, fixed.
EWN is destroyed–> midbrain
Pupils are pinpoint
Pons (descending sympathetics through pons are cut off)
