Persistent Vegetative State Flashcards
consciousness
state of full awareness of self and environment
wakefeullness
ability to have basic reflexes
awareness
ability to carry out complex thought processes
psychological unconsciousness
state of unawareness or repressed ideas
neurological unconsciousness
paralytic coma due to brain disfunction
role of ascending reticular activating system ARAS
alerting and arousal
structures in the ascending reticular activating system
pontine tegmentum
thalamus
lateral prefrontal cortex
which parts of the hypothalamus promote arousal and sleep
arousal - tuberomammillary nucleus
sleep - venterolateral preoptic nucleus
which nucleus is involved in the circadian clock
suprachiasmatic nucleus
what can cause disorders of consciousness
structural brain lesions
metabolic and nutritional disorders
exogenous toxins
CNS infections and sepsis
seizures
hypo/hyperthermia
trauma
scales for assessing consciousness alteration and duration
GCS glasgow coma scale
LOC loss of consciousness
4 outcomes of coma
brain death
vegetative state
locked in syndrome
recover wakefulness
3 main categories of unconsciousness
comatose
vegetative
minimally conscious
comatose state
state of complete unresponsiveness in which pt lies with eyes closed and cannot be aroused to respond to any stimuli
stupor
state of unresponsiveness similar to coma but pt will respond to strong stimuli
difference between deep sleep and coma
no REM in coma
how long does coma usually last
a couple of weeks
locked in syndrome
state of unresponsiveness where pt lies with eyes closed and cannot be aroused to respond to any stimuli however retains eye movement and is fully conscious
injury to which brain area is the primary cause of locked in syndrome
ventral pons - interrupts corticospinal and corticobulbar tracts
how can pts with locked in syndrome communicate
e-Tran frame
brain computer interface
akinetic mutism
condition of apparent alertness with a lack of almost all motor functions including speech, gestures, and facial expression
brain areas most commonly affected in akinetic mutism
frontal lobe
basal ganglia
mesencephalothalamic regions
which diseases are associated with akinetic mutism
alzheimers disease
picks disease
creutzfeldt jakobs disease
vegetative state
spontaneous eye opening but no evidence of purposeful behaviour suggesting awareness of self or environment
what posturing may be present in vegetative state
decorticate
decerebrate
how long does persistent vegetative state last
at least 1 month
how long does permanent vegetative state last
at least 12 months after TBI
at least 3 months after non traumatic causes
minimally conscious state
condition of sevrely altered consciousness in which there is a definitive but often subtle and inconsistent behavioural evidence of self or environmental awareness
confusional state
interactive communication with amnesia, confusion, and hypokinetic/agitated/labile behaviour
post confusional state
resolution in amnesia and confusion and functional independence, but higher level cognitive impairments and deficits in self awareness, social awareness, behavioural and emotional regulation
what effect prognosis of vegetative state
cause
severity
site of damage
duration
depth of consciousness
what % of pts recover from a vegetative state lasting over 1 year
10%
what care is needed for a pt in vegetative state to keep pt alive
clinically assisted nutrition and hydration
moving to prevent bedsores and muscle atrophy
when does the decision to withdraw feeding tubes from a comatose pt need to go to court or not
hospital staff+family agree - no court
1 party disagrees - court of protection
vegetative state management
stabilise ABC
ICU admission
control ICP
establish cause
CANH
bedsore and muscle atrophy prevention
methods for assessing consciousness
auditory event related potential
PET scan
blood oxygen level dependent fMRI
what do auditory event related potentials identify
response in primary auditory and prefrontal cortices to change in monotonous sequence of sounds - MMN(negative component), P300(positive component)
why there issues assessing consciousness based on P300 absence
P300 absent in 10-20% healthy individuals
what do PETs measure to assess brain activity
glucose uptake
what do BOLD fMRIs measure to assess brain activity
cerebral bloodflow via difference between oxyHb and deoxyHb
how do the PET and MRI scans of a person with locked in syndrome differ from that of a healthy person
no difference
effects of sensory stimulation of vegetative pts
increase responsiveness
avoid sensory deprivation
enrich environment
promote neural plasticity
involve family - favourite smells, tastes, images, etc
which drug can improve functional recovery rate in early stages of unconsciousness disorders
amantadine
amantadine mechanism
NMDA antagonist
blocks dopamine reuptake
amantadine administration
100-200mg 2x/day for 4wks 4-16wks after injury
which drug can cause short term arousal in unconscious pts
Zolpidem
how does zolpidem possibly work
increase thalamic excitatory influence on prefrontal cortices by activating GABAa in GPi
