B7-049 Coma Flashcards
midline structural lesions of the […] can affect the RAS on both sides, leading to coma
diencephalon (thalamic area)
an occlusion of […] artery could cause diencephalic coma
top of basilar
midline structural process affecting the brain stem
subtentorial
space occupying lesion pushing the brain down and compressing the RAS causing coma
supratentorial
diffuse toxic process affecting the entire cortex leading to coma
metabolic
two stages of supratentorial lesion
- diencephalic stage (early)
- midbrain stage (late)
cortex and RAS working completely fine, but in coma
psychogenic
psychological stressors precedes coma
pyschogenic
delirium w/o focal signs precedes coma
metabolic
sudden onset coma [2]
diencephalic
subtentorial
focal signs precede coma
supratentorial
hemorrhage in the pons is an example of process causing […] coma
subtentorial
neurologic examination in coma involves [4]
level of consciousness
pupils
extraocular movements
motor function
the pupillary parasympathetic system is […] to toxic-metabolic processes
resistant
the pupillary sympathetic system is […] to toxic-metabolic processes
sensitive
almost all patients with coma will experience […] dysregulation
sympathetic
pupils will be mid-range and reactive in patients experiencing […] coma
psychogenic
pupils will be small and reactive in patients experiencing […] coma [3]
metabolic
diencephalic
early stage supratentorial
(due to unopposed parasympathetic stimulation)
pupils will be mid-range and unreactive in patients experiencing […] coma [2]
late stage supratentorial
subtentorial
(due to loss of both sympathetic and parasympathetic systems)
unreactive pupils tell you the […] system is not working
parasympathetic
if the pupils are small, this tells you the […] system is intact
parasympathetic
small pupils are typically […]
reactive
fast eye movements (saccades) require that the […] is intact
frontal eye fields
if you have fast eye movements, your […] is intact
cerebral cortex
(not in coma)
fast eye movements is […] to toxic metabolic processes
sensitive
slow eye movements indicates […] is working
brainstem
slow eye movements is […] to toxic metabolic processes
moderately sensitive
the presence of slow eye movement means that
there is no brainstem lesion
(the absence does not necessarily mean there is though)
intact slow movements means the […] is intact
brainstem
normal oculocephalic reflex
eyes continue to point in the same direction while head is turned side to side
(brainstem is working)
what do you expect to see when cold calorics is used on a patient in a coma if their brainstem is intact?
slow tonic movements of the eye toward the side being irrigated
which method would be best to test the eye movements of a patient in a coma with neck trauma?
cold calorics
(don’t want to move their head side to side as with oculocephalic)
if you are doing cold calorics on a patient in a coma and you see saccades, the patient is […]
not in a coma
(frontal eye field is working)
if you’re suspicious a patient is in psychogenic coma, what eye movement test is helpful in determining that?
cold calorics
(will have fast saccades –> not in true coma)
intact fast eye movements
intact slow eye movements
psychogenic
absent fast eye movements
intact or abnormal slow eye movements
metabolic
absent fast eye movements
intact slow eye movements [2]
diencephalic
early stage supratentorial
brainstem intact
absent fast eye movements
abnormal slow eye movements [2]
late supratentorial
subtentorial
[…] motor findings characterize most patients in coma, regardless of cause
bilateral symmetric
(bilateral corticospinal tract findings)
localized response is a […] prognostic indicator for a patient in a coma
good
flexion of upper extremities
extension of lower extremities
decorticate posturing
extension of upper extremities
extension of lower extremities
decerebate posturing
motor responses in coma [3]
localized response
decorticate posturing
decerebate posturing
does decorticate or decerebate posturing have a worse prognosis?
decerebate
a lesion between the cortex and the red nucleus causes […] posturing
decorticate
a lesion between the red nucleus and the vestibular nuclei causes […] posturing
decerebate
motor response that might be seen with patients in a psychogenic or metabolic coma
localized response
(don’t put too much stock in abnormal posturing though)
motor response that might be seen with patients in a diencephalic or early supratentorial coma
decorticate posturing
(don’t put too much stock in abnormal posturing though,not specific)
motor response that might be seen with patients in a late supratentorial or subtentorial coma
decerebate posturing
(don’t put too much stock in abnormal posturing though)
a CT can help diagnose a […] mass lesion
supratentorial
what types of coma will have an intact brainstem? [4]
psychogenic
metabolic
diencephalic
early supratentorial
what types of coma will not have an intact brainstem? [2]
late supratentorial
subtentorial
most common cause of coma
metabolic
workup for toxic metabolic coma should include [4]
routine labs
stat lumbar puncture
EEG for seizure hx
MRI
patients with […] will open their eyes to pain
stupor
the neurologic exam on a normal person would be most like the neurologic exam of a patient in what type of coma?
psychogenic
in most patients with coma, the […] system controlling pupillary […] is affected
sympathetic
dilation
the presence of fact eye movements indicates the […] is intact
frontal eye fields
most important element of neurologic examination to determine the cause of coma
pupillary activity
the pathological absence of consciousness
coma
the physiologic absence of consciousness
sleep
patients with […] will open their eyes to speech
lethargy
patients in […] will not open their eyes
coma
differential for subtentorial coma
pontine or cerebellar hemorrhagic stroke (would see on CT)
basilar artery ischemic stroke (would not see on CT)
how would you determine if it is psychogenic?
look for fast eye movements
look for eye tracking (mirror in front of face)
what would you do to differentiate a metabolic vs diencephalic stroke?
look for obvious toxic metabolic cause (labs)
if none, stat CT angiogram to look for top of the basilar occlusion
most common cause of metabolic coma in ER
drugs
eyes look toward the brain lesion when the lesion is in the […]
frontal eye fields
(seen in MCA stroke)
eyes look away from the brain lesion (toward the hemiplegia) when the lesion is in the […]
PPRF
bilateral mammilary body lesions would be seen in […] syndrome
Wernicke-Korsakoff
bilateral amygdalal lesions are seen in
HSV-1 encephalitis
(causes hyperphagia, hypersexuality, hyperorality)
is decorticate posturing a specific finding?
apparently not
can be seen in toxic metabolic processes and structural processes involving the RAS
the appropriate study to look for a supratentorial process in the ER is
non-contrast CT
[…] eye movements can only be present when consciousness is preserved
fast
fast eye movements require intact
frontal eye fields
an overdose of […] could cause coma with fixed dilated pupils
anticholinergics
(amytriptyline, diphenhydramine, etc)
most causes of metabolic coma would not affect the […]
pupils
hallmark of psychogenic coma
presence of fast eye movements
