(37) Coma Flashcards
lethargy vs hyperinsomnia
lethargy = sleepy but easily aroused hypersomnia = excessively sleepy but normal cognition when awakened
obduntation vs stupor
obduntation = mental blunting with decreased alertness
stupor = eye open only after vigorous stimulation and then go back to deep sleep
coma vs stupor
stupor = eye open only after vigorous stimulation and then go back to deep sleep
coma = eyes remain closed even after vigorus stimulation
defn of delerium
disorientated, hallucinations, misperception of sensory stimuli; fluctuate between quiet/sleepy and alert/agitated
What is “abulia”? Damage to what area causes it?
awake but apathetic and no sponteneity
bilateral frontal lobe disease, lobotamized
What is “akinetic mutism”? Damage to what area causes it?
silent, altert looking but no mental activity with vigorous stimulation
frontal lobes and hypothalamus
Difference between minimally conscious states and vegetative state?
MCS = fragements of awareness
vegetative = awake, no awareness or meaningful interaction with the environment
can reach for objects, grunt or gesture in response to a command, visually fixate and track but are unable to do much more
minimally conscious state
What are the 2 components of consiousness
arousal = ascending tracts content = cortical circuits (awareness and cognition)
lesions in what areas are known to cause coma
extensive bi-hemispheric disease
diencephalon (thalamus and hypothalamus)
peri-aqueductal gray
upper 1/3 of ponitine tegmentum
areas that produce coma when damaged are called
ascending arousal system
Describe the parts of the ascending arousal system and what they do
2 cholinergic nuclei that inhibit thalamic neurons that synchronizes with cortex to induce sleep
monoaminergic nuclei that improve signal to noise ration and avoid misperception of incoming stimuli
sleep promoting center of the brain. how does it work?
VLPO–sends GABA and galanin (inhib neuropeptide) to the many nuclear centers that promote wakefulness
ascending arousal system receives feedback from what sources
thalamus, limbic system, fronto-parietal assc cortex
…these areas mediate emotional memories and permit concentrated attention to one sensory modality when necessary…
loss of feedback to ascending arousal system leads to…
abulia or akinetic mutism = apathy and indifference to sensory stimuli
…i.e. cannot be aroused?….
What parts of the brain herniate in a transtentorial heriation
temporal lobe or uncus (of temporal lobe)
complications of uncal herniation
- compression of occulomotor nerve (mydriasis + eye down and out)
- compress midbrain –> Duret’s hemorrages
- PCA compression –> ipsilateral stroke in occipital lobe
what is a bilateral uncal herniation called?
central herniation
herniation that pushes brain under the falx cerebri
falcrine herniation (herniation of cingulate gyrus)
complication of falcrine herniation
ACA compression (/stroke)
cause of lethargy in central herniations
compression of reticular grey in thalami
cause of small reactive pupils in central herniation
compression of hypothalamus
if central herniation is not corrected, the pupils will go from being small to… why?
fixed in mid position bc para will get knocked out too when the herniation compresses the midbrain (Endinger-Westphal nucleus)
Late signs of central herniations
flexor then extensor posturing then cheyne-stokes respirations
what is the distinct syndrome caused by pontine hemorrhages
abrupt coma + pin point pupils + flaccid paralysis or flexor rigidity + horizontal gaze paralysis (eyes can only move vertically) + ocular bobbing (up and down)
What are patients that have pontine hemorrhages at risk for
locked in syndrome
in metabolic encephalopathy pupils are (reactive or inactive to light)
reactive
**in structural causes of coma they are inactive
3 most common causes of encephalopathy in the elderly
dehydration, infection, drug intoxication
presentation of metabolic encephalopathy
non-focal neuro exam defectis
negative CT
reactive pupils
myoclonis, asterixes, and tremor
what drugs are empriacally given to pateints in a coma
D50 THEN thamine, naloxone
**D50 BEFORE thiamine to prevent Wernicke’s enchephalopathy
normal vital signs suggest what kind of coma
psychogenic
cheyne stokes respirations can be an early sign of
central and uncal herniations
decerebrate posturing =
extensor
flexor center is in ____ and extensor center is in _____
flexor = midbrian extensor = pons
extensor posturing predominates when ___ is lost/damaged
midbrian / flexor center
decorticate posturing =
flexor
flexor or extensor posturing worse
extensor
poor prognosis if on day __ of coma, the ___ reflex is absent and absence of purposeful _____
day 3
no corneal reflex and no purposeful movements
aneurysm in ___ artery may also compress CN III
posterior communicating
