B7.049 Prework: Disorders of Consciousness

Question 1

coma

Answer 1

pathological absence of consciousness

Question 2

determination of levels of consciousness

Answer 2

stimulus required for eye opening

Question 3

awake

Answer 3

spontaneous eye opening

Question 4

lethargic

Answer 4

speech stimulus required for eye opening

Question 5

stupor

Answer 5

pain stimulus required for eye opening

Question 6

coma

Answer 6

no stimuli can open eyes

Question 7

which systems can be affected to cause coma

Answer 7

cortical systems

RAS

Question 8

lesion categories that can lead to coma

Answer 8

midline (RAS)
-this section more resistant to toxic/metabolic stimuli than cortical neurons
diffuse (cortex)

Question 9

diencephalic lesion

Answer 9

affects RAS at level of thalamus
possible basilar occlusion
sudden onset

Question 10

subtentorial lesion

Answer 10

affects RAS at level of brainstem

sudden onset of coma

Question 11

supratentorial lesion

Answer 11

early: diencephalic
late: brainstem
caused by space occupying lesion that distorts the RAS due to herniation
focal signs can precede coma

Question 12

metabolic lesion

Answer 12

diffuse throughout the cortex

delirium can precede coma

Question 13

psychogenic lesion

Answer 13

psychological stressors precede coma

Question 14

why is a neurologic examination useful in coma

Answer 14

• anatomic proximity of pupillary and oculomotor subsystems to RAS
• selective susceptibility of neurologic subsystems to metabolic insults (cortex susceptible, pupillary system resistant)

Question 15

components of neuro exam in coma

Answer 15

level of consciousness
pupils
extraocular movements
motor function

Question 16

parasympathetic pupillary system susceptibility

Answer 16

resistant to toxic-metabolic processes

Question 17

sympathetic pupillary system susceptibility

Answer 17

sensitive to toxic-metabolic processes

Question 18

psychogenic pupil

Answer 18

mid range

reactive

Question 19

metabolic pupils

Answer 19

small (sym knocked out)

reactive (para ok)

Question 20

diencephalic pupils

Answer 20

small (sym knocked out in anatomic region)

reactive (para region not affected)

Question 21

supratentorial pupils

Answer 21

early: small, reactive
late: mid range, unreactive

Question 22

subtentorial pupils

Answer 22

mid range (no para or sym function)
unreactive

Question 23

fast eye movements in coma

Answer 23

if intact: cortex intact

sensitive to toxic-metabolic processes

Question 24

slow eye movements in coma

Answer 24

if intact: brainstem intact

moderately sensitive to toxic-metabolic processes

Question 25

how to assess eye movements in coma

Answer 25

``` oculocephalic reflex (move neck and see if eyes stay centered) cold calorics (show slow deviation to the side that is being irrigated, should not see nystagmus if in a real coma) ```

Question 26

psychogenic eye movements

Answer 26

intact fast | intact slow

Question 27

metabolic eye movements

Answer 27

absent fast | intact or abnormal slow

Question 28

diencephalic eye movements

Answer 28

absent fast | intact slow

Question 29

supratentorial eye movements

Answer 29

early: absent fast, intact slow late: absent fast, abnormal slow

Question 30

subtentorial eye movements

Answer 30

absent fast | abnormal slow

Question 31

motor function in coma

Answer 31

bilateral, symmetric motor abnormalities characterize most patients including these with metabolic coma bilateral corticospinal tract findings

Question 32

different types of motor responses in coma

Answer 32

decorticate: abnormal flexion (lesion between cortex and red nucleus) decerebrate: abnormal extension (lesion between red and vestibular nuclei)

Question 33

usefulness of motor response in localizing source of coma

Answer 33

not very

Question 34

usefulness of CT in localizing source of coma

Answer 34

used to evaluate for supratentorial mass | helps distinguish between diencephalic, supratentorial, or subtentorial based on findings

Question 35

brainstem intact lesions

Answer 35

``` psychogenic metabolic diencephalic early supratentorial have intact slow eye movements and pupillary response ```

Question 36

brainstem not intact lesions

Answer 36

late supratentorial subtentorial pupils unreactive abnormal slow eye movements

Question 37

cortex intact lesions

Answer 37

psychogenic | pupils reactive and fast eye movements can be present

Question 38

coma algorithm

Answer 38

1. check if cortex or brainstem intact (eye movements and pupils) 2. check for mass (CT)

Question 39

psychogenic coma prevalence

Answer 39

5%

Question 40

metabolic/diencephalic coma prevalence

Answer 40

60%

Question 41

supratentorial coma prevalence

Answer 41

25%

Question 42

subtentorial coma prevalence

Answer 42

10%

Question 43

further workup for toxic metabolic comas

Answer 43

routine labs (kidney failure, liver failure, etc) stat lumbar puncture EEG if history or signs of seizures (uncommon) MRI