Quiz 1 - definitions, substrates, evaluation of consciousness Flashcards Preview

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Flashcards in Quiz 1 - definitions, substrates, evaluation of consciousness Deck (53):
1

coma definition

- pathological
- unconscious
- cannot be aroused
- deep vs light - in light reflex motor response can be aroused by noxious stimulus

2

stupor definition

- pathological
- reduced consciousness
- can be aroused with intense or purposeful stimulation

3

range of stupor

drowsiness to deep stupor

4

sleep definition

- non-pathological
- active and reversible state of consciousness

5

hysterical coma definition, how differentiated?

- feigned or subconsciously assumed depression of consciousness
- will have normal EEG, nystagmus on irrigation of auditory canal, no abnormal neurologic signs

6

explain the base of the pons exception

- most of the time when someone is conscious yet unresponsive it is obvious what (GB syndrome, MG, porphyria)
- damage to base of pons - patient becomes acutely unresponsive but will keep vertical and convergent eye movement, sight, and hearing
- LOCKED IN syndrome

7

reticular vs hemispheric involvement in depression of consciousness

- reticular involves mass lesions above or below the tentorium affecting reticular function (less common)
- hemispheric involvement is almost always metabolic and depresses the reticular formation indirectly

8

importance of cortical hemispheres in consciousness

- anything causing diffuse dysfunction of the cortex, whether destruction or encephalopathy, will cause stupor and/or coma

9

relationship between cortex and rostral reticular formation

- rostral reticular formation is termed the reticular activating system and the cortex can't function without it
- reticular activating system can work without cortex and maintain a crude sleep-wake vegetative state
- cortex is much more sensitive to toxic stimuli

10

common causes of direct damage to reticular formation

- hemorrhage
- neoplasm
- abscess
- trauma
- inschemia/infarction

11

what part of the temporal lobe usually herniates the tentorial notch?

uncus

12

what pattern of deterioration is caused by tentorial notch herniation

rostrocaudal deterioration

13

order of brain deterioration in rostrocaudal process

- diencephalon
- mesencephalon
- pons/medulla

14

evaluation of coma is primarily to differentiate between which two things?

- coma caused by diffuse cortical damage vs that caused by damage for reticular activating system

15

components of neuro eval of coma patient

- LOC
- resp pattern
- pupil size
- oculomotor vestibular function
- motor function

16

what does drowsy look like?

opens eyes to stimulation but goes back to eyes closed when not stimulated

17

what does deep stupor look like?

needs vigorous stimulation to get response

18

what does deep coma look like?

no reaction even to noxious stimuli

19

if best motor response is withdrawal or posturing...

patient is not conscious

20

respiration in diffuse cerebral cortical dysfunction

- drowsiness, sighing respirations, yawning

21

when is a Cheyne Stokes resp pattern seen?

- damage to diencephalon or mesencephalon
- sometimes in diffuse cerebral cortical dysfunction

22

what is Cheyne Stokes respiration?

- crescendo-decrescendo pattern
- periods of apnea of variable length

23

when is Cheyne Stokes respiration most apparent?

during sleep

24

respiration in damage to lower mesencephalon/upper pons

- central neurogenic hyperventilation, 20-40 rpm
- danger of respiratory alkalosis
- deep breathing

25

respiration in damage to lower pons

- irregularly irregular breathing
- inconstantly varying rhythm and rate
- may be hyperventilation
- may be apneustic breaths (hold after inspiration)

26

respiration in damage to medulla

- depression and ultimately apnea

27

pupils in isolated damage or diffuse damage to cerebral cortex

no change

28

pupils in damage to diencephalon and why?

- constricted pupils because damage to thalamic pathways that carry sympathetic dilators
- still reactive to light

29

pupils in damage to caudal diencephalon/upper mesencephalon

- constricted
- pupils sluggish in reacting to light

30

pupils in mesencephalon damage

- CNIII damage (loss of parasympathetics)
- pupils widely dilated (7-9mm)
- no reaction to light

31

pupils in damage to caudal levels of midbrain

- CNIII damage as in mesencephalon
- added damage to sympathetics
- pupils midsized (4-7mm)
- no reaction to light

32

pupils in damage to pons/medulla

- same as midbrain
- midsize and fixed

33

pupils in isolated pons or isolated medulla damage with maintained integrity of midbrain

- only loss of sympathetics
- very constricted pupils (1mm or less)

34

pupils in suppression of brainstem by drugs

- loss of light reflex

35

what happens in auditory ice water test if reticular formation is functional but there is diffuse cerebral damage?

- eyes go toward ice water side and stay there for minutes
- no nystagmus

36

in terms of eye movement, diffuse damage to cerebral cortex results in loss of.....

- fast component of vestibulo-ocular reflex (nystagmus)
- degree of suppression is proportionate to degree of damage

37

eye movements in damage to midbrain

dysconjugate eye movements

38

tonic conjugate deviation of the eyes during caloric stimulation indicates that....

the brainstem/reticular activating system is still intact

39

eye movement in damage to brainstem through the pons

- no reaction at all to caloric stimulation
- no corneal reflex

40

how will a lightly stuporous patient react to noxious stimuli?

- localize it
- knock it away or grab it

41

how will a deep stupor patient react to noxious stimuli?

- withdrawal (stereotyped)

42

noxious stimulation reaction of a comatose patient with damage to diencephalon

decorticate posturing

43

elements of decorticate posturing

- flexion of arms, wrists, fingers
- extension of lower limps
- may be asymmetric at first, appearing first on side of greater damage

44

noxious stimulation reaction of a comatose patient with damage to mesencephalon or upper pons

decerebrate posturing

45

elements of decerebrate posturing

extension and internal rotation of arms and legs

46

what motor response is usually seen in pontine and medullary damage?

flaccid paralysis

47

last reflex that can still be detected as metabolic dysfunction progresses

light reflex

48

5 categories of metabolic dysfunction

1) oxygen
2) toxic
3) acid-base/ionic
4) postictal
5) traumatic

49

examples of toxic metabolic dysfunction

endogenous - liver, kidney failure
exogenous - drug overdose
CNS - meningitis, encephalitis

50

what is most commonly the cause of depressed consciousness in a demented patient?

- metabolic
- demented patient's remaining cortical function is much more sensitive to stressors such as renal dysfunction, infections, drugs...

51

two major causes of vegetative state

- hypoxic ischemia
- shear force from trauma

52

are those in vegetative state conscious? aware?

no and no

53

contrast minimally conscious state with vegetative state

- require same interventions
- MCS can respond to stimuli and stimulant medications
- MCS partial or intermittent evidence of awareness to self and environment