COMA Flashcards
What is a coma?
State of unresponsiveness, in which a patient cannot be aroused
Awareness is
Content of consciousness
Awareness occurs as a result of …
activity in cerebral cortex (supratentorial, matter) - loss of awareness seen in vegetative state
Arousal is
level of consciousness/alertness (high in normal wakefulness)
Arousal occurs as a result of
activity with specific brainstem and diencephalic structures (deep in thalamus)
In a coma, anesthesia or sleep how is awareness and arousal?
Both are zero
In a vegetative state how is arousal…(1)
how is awareness (2)
Arousal is HIGH
Awareness is LOW
In a minimally conscious state how is arousal…(1)
how is awareness (2)
- Arousal is HIGH
2. Awareness is ABOVE zero.. but low
In lesions causing coma what happens to cerebral cortex?
BILATERAL damage of both hemispheres or ascending arousal system including
1) paramedian region of upper brainstem or
2) diencephalon on both sides of the brain
In locked in syndrome what 3 things in intact
Awareness
Vertical eye movements
Vision
Where does lesion in locked in syndrome occur
BELOW level of arousal,
in the caudal pons - wipe out cortico spinal and corticobulbar tract
What are some causes of coma ?
- structural brain disease (supratentorial or infra outside dura, inside dura, blood, pus, tumor)
- destructive lesions - not extra tissue, loss of oxygen, encephalitis (supra or infra tent)
- epilepsy, diffuse intrinsic lesions in the brain
- metabolic disease - severe anoxia, low blood glucose, liver failure, acid-base imbalances
What is tonsillar herniation
swelling within cerebellum after infarct, edematous, cerebellum expands, pushes forward
1) first thing that happens is respiratory pause - presses on medullary respiratory center
how do you treat a tonsillar herniation?
suboccpital craniotomy
how do you treat a patient with an epidural hematoma?
- ABCs
REDUCE ICP - elevate the head 30 deg
- hyperventilate - pco2 25-30 (contrict arterioles in brain )
- mannitol 20% over 30ml (diuertic pull out interstitial fluid)
evacuate the bleed