Lecture 53: Disorders of consciousness Flashcards Preview

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Flashcards in Lecture 53: Disorders of consciousness Deck (41):
1

What is the location of the source nuclei for the ascending reticular activating system (ARAS)? NT?

Ponto-mesencephalic junction; ACh

2

Pathway (three regions) responsible for "arousal"

ARAS --> thalamus --> thalamo-cortical relays

3

Brain region responsible for "awareness." Is it easy to "knock the lights out" here?

Cortex; NO -- would have to damage cortex BILATERALLY to cause loss consciousness

4

What type of stroke can cause mass effect? What brain region can this effect?

Epidural hematoma; brainstem

5

What scary transmitted disease can cause loss of consciousness at the level of the cortex?

Creutzfeld-Jacob Disease (CJD)

6

Levels of consciousness/arousal (6)

Awake, somnolent (full arousal by auditory/tactile), lethargic (sub-arousal by non-noxious), obtunded (depressed LOC, still responds to non-noxious), stupor (req noxious stimuli), coma (unresponsive)

7

Content of consciousness: levels of awareness (3)

Alert --> inattentive --> vegetative

8

Neurologic examination of coma features (3, if you don't know the wheres or the whys...)

Respiratory pattern, eye function, motor responsitivity (listen to breath and look at the eyes)

9

Respiratory pattern w/ forebrain dysfunction

Cheyne-Stokes respiration (hyperventilation with pauses)

10

Respiratory pattern w/ midbrain dysfunction

Hyperventilation

11

Respiratory pattern w/ rostral pons dysfunction

Apneusis

12

Respiratory pattern w/ caudal pons dysfunction

Ataxic breathing (disorganized)

13

Respiratory pattern w/ medulla dysfunction

Respiratory arrest

14

Pupil patterns w/ thalamic dysfunction

Small reactive

15

Pupil patterns w/ herniation

One fixed dilated (impacting para on CN III)

16

Pupil patterns w/ pretectal dysfunction

Fixed dilated

17

Pupil patterns w/ midbrain dysfunction

Fixed mid-size

18

Pupil patterns w/ pontine dysfunction

Pinpoint

19

Corneal reflex (afferent/efferent). Lesions localize where?

Afferent: CN V; Efferent: CN VII; pons

20

Two clinical provocative maneuvers for VOR

Oculo-cephalic/Doll's eyes reflex; calorics

21

Oculo-cephalic reflex

Tests VOR: eye tilt to provoked head movements

22

Oculo-cephalic reflex w/ right lateral pontine lesion

Cannot look to the right (no pontine lateral gaze function)

23

Cold water calorics w/ right lateral pontine lesion

No slow gaze drift to the right side

24

Oculo-cephalic reflex w/ bilateral midbrain lesion

Turn right: cannot adduct right eye; Turn left: cannot adduct left eye; Turn up/down: eyes stay still

25

Cold water calorics w/ bilateral midbrain lesion

Cannot adduct proper eye during application to either ear (no medial rectal activity in III)

26

In full consciousness, what happens to Doll's eye reflex?

+ or - due to ability to inhibit it

27

With knocked out cortex but OK brain stem, what happens to Doll's eye reflex?

+

28

With knocked out cortex AND brain stem, what happens to Doll's eye reflex?

-

29

Descriptive characteristics of motor responsivity (6)

Purposeful, localize, withrdaw, decorticate, decerebrate, none

30

Knocked out motor cortex/thalamus...

No contralateral purposeful movement

31

Knocked out upper midbrain...

Flexion response/ decorticate posture (high lesion, body goes up)

32

Knocked out upper pons...

Extension response/ decerebrate posture (low lesion, body goes down)

33

What eye movements are spared in locked-in syndrome

Voluntary opening, vertical movements, covergence

34

Categories of consciousness impairment (3 w/ subtypes for 1)

Coma, vegetative (persistent, permanent), minimally conscious

35

Arousal/awareness in vegetative state

Full arousal, no awareness

36

Arousal/awareness in minimally conscious state. Describe.

Full arousal, fluctuating partial awareness (eye movements, simple commands, purposeful behavior)

37

Arousal/awareness in coma

No arousal, no awareness

38

T/F: Sleep wake cycles in vegetative state

True

39

Main point of coma prognosis

Longer the absence of key brainstem function signs (breathing, motor responsivity, eyes) = worse prognosis

40

Brain death

Absent midbrain reflxes (pupillary reactivity); absent pontine reflexes (VORs, corneal); absent medullary reflexes (apnea)

41

To determine brain death, must do...(2)

Brain stem function testing; apnea testing

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