Clinical correlation: COMA

Question 1

what is normal oculocephalic testing?

Answer 1

when you turn your head the eyes move conjugately to the opposite direction

Question 2

what are the 4 levels of conciousness?

Answer 2

normal : no external stimulation needed
somnolent ( sleepy): external stimulation> NI wakefullness
obtunded: with external stimuli don’t get normal wakefulness i.e. drift off after wakefulness
COMA: no wakefulness

Question 3

when would you get a cheyne-stokes respiratory pattern?

Answer 3

in lesion of the diencephalon ( includes the thalamus)

Question 4

how would you characterize the cheyne stokes breathing pattern?

Answer 4

waxing and waning, person could even stop breathing

Question 5

what is central neurogenic hyperventilation is characterized by what?

Answer 5

really fast breathing

Question 6

a lesion where causes central neurogenic hyperventilation?

Answer 6

reticular activating system in the midbrain above the colliculus essentially cutting off the brainstem and diaphragm from the breathing center causing abnormal breathing

Question 7

a lesion where causes aPneustic respiration?

Answer 7

a lesion in the Pontine tegmentum (mid pons breathing centers) thus only the medulla breathing center is left

Question 8

how would you characterize apneustic respiration?

Answer 8

inspiratory spasms

Question 9

how would you characterize ataxic breathing?

Answer 9

characterized by complete irregularity of breathing, with irregular pauses and increasing periods of apnea

Question 10

how does pt present and what is lesioned in a tectal pupillary light reflex?

Answer 10

large fixed pupils, w/ no reaction to light,

isolated lesion in tectum

Question 11

how does pt present and what is lesioned in a pinpoint pupillary light reflex?

Answer 11

isolated lesion in the pons sympathetics impaired so can’t dilate

Question 12

where is the lesion if a patient has midposition fixed dilated pupil and is in a coma?

Answer 12

the midbrain

Question 13

where is the lesion if the patient has one dilated and fixed eye and when light shined in the normal eye there is intact consensual and direct pupillary reflex but i direct light in the dilated eye doesn’t work neither will consensual constrict ( i.e. when light shined in good eye bad eye won’t constrict?

Answer 13

III Nerve lesion (uncal)

Question 14

what would occur during pupillary reflex in a diencepahlic lesion?

Answer 14

the pupils will be small and reactive

Question 15

what occurs in a metabolic pupillary reflex?

Answer 15

the eyes are small and reactive and there is a lesion in the tectum of the midbrain ( starting to lose some of the sympathetics.

Question 16

what does the occularvestibular facilitate?

Answer 16

it facilitates eye movement in the opposite direction of head movement.

Question 17

describe how the occulovestibular reflex works.

Answer 17

when the vestibular system sense a shift in your movement through shift of fluids in the ear the ipsilateral medial vestibular nucleus signals the ipsilaterlal CN 6 and via the MLF the contralateral CN# to move in unison.

Question 18

what is decorticate posturing?

Answer 18

(Spastic hemiparesis)
lesion above the red nucleus of the midbrain
- arm, wrist, finger flexion, adduction of upper extremity
- leg extension, internal rotation, plantar flexion

Question 19

what is decerebrate posturing?

Answer 19

lesion below the red nucleus, release of vestibulospinal output ( i.e dominated by the vestibulospinal tracts)
- internal rotation of arms, clenching of jaws, stiff extension of limbs - extension of trunk and legs (opisthotonos), plantar flexion

Question 20

the _________ ___________ system in the _______ keeps awake. and we only need one side for consciousness

Answer 20

reticular activiating system in the midbrain

Question 21

what is the respiratory pattern in bilateral midbrain stage?

Answer 21

sustained regular hyperventilation ( occurs because only the lower respiratory centers are working).

Question 22

what is the pupillary size and reaction in bilateral midbrain stage?

Answer 22

Irregular, no pupillary constriction

Question 23

what is the oculocepahilc and oculovestibuar reflex in the bilateral midbrain stage?

Answer 23

Disconjugate eye reflexes - only CN6 ( since the is in the pons)/ abduction present but the CN III of opposite eye doesn’t work because that is in the midbrain

Question 24

what is the motor responses at rest and to stimulation in bilateral midbrain stage?

Answer 24

Motionless or bilateral ( but mostly on the contralateral side of the lesion) Decerebrate posturing upon stimulation( i.e trying to arouse them)

Question 25

what is the respiratory pattern in bilateral diencephalic stage?

Answer 25

Cheyenes- Stokes

Question 26

what is the pupillary size and reaction in bilateral diencephalic stage?

Answer 26

Small pupils with small range of constriction

Question 27

what is the oculocepahilc and oculovestibuar reflex in the bilateral diencephalic stage?

Answer 27

Eye reflexes normal (because brainstem is unaffected) so both 3 and 6 are intact

Question 28

putting ice water into the left ear would do what to the eyes?

Answer 28

cause the eyes to move to left because the body thinks it’s moving to the right

Question 29

what is the motor responses at rest and to stimulation in bilateral diencephalic stage?

Answer 29

Motionless, bilateral Decorticate posturing upon stimulation ( i.e. trying to arouse them) since it’s above the red nucleus

Question 30

what is the respiratory pattern in unilateral diencephalic stage?

Answer 30

Eupneic ( normal) with deep sighs or cheyne stokes

Question 31

what is the pupillary size and reaction in unilateral diencephalic stage?

Answer 31

Small pupils with small range of constriction ( sympathetics are impaired but they react to light b/c the midbrain is fine)

Question 32

what is the oculocepahilc and oculovestibuar reflex in the unilateral diiencephalic stage?

Answer 32

Eye reflexes normal (because brainstem is unaffected) so both 3 and 6 are intact

Question 33

what is the motor responses at rest and to stimulation in unilateral diencephalic stage?

Answer 33

Motor response on ipsilateral side of body , (+) Babinski’s sign on contralateral side of body

Question 34

what is the respiratory pattern in bilateral pontine stage?

Answer 34

slow, irregular Ataxic breathing or eupneic (normal) although shallow and more rapid than normal

Question 35

what is the pupillary size and reaction in bilateral pontine stage?

Answer 35

No pupillary constriction

Question 36

what is the oculocepahilc and oculovestibuar reflex in bilateral pontine stage?

Answer 36

No eye reflexes

Question 37

what is the motor responses at rest and to stimulation in bilateral pontine stage?

Answer 37

Motionless, Flaccid muscles (no motor response because vestibular nuclei are located here) or occasional flexion of lower extremities when feet are stroked, and occasional bilateral babinksi

Question 38

what is the respiratory pattern in late 3rd nerve stage ( midbrain)?

Answer 38

regular sustained hyperventilation ( coming from pons therefore you know midbrain is impaired) or rarely cheyne stokes

Question 39

what is the pupillary size and reaction in late 3rd nerve stage ( midbrain)?

Answer 39

Ipsilateral pupil widely dilated, does not constrict; ptosis ( the contralateral midbrain is working since CN III os working on that side but no ipsilateral side midbrain is lesioned)

Question 40

what is the oculocepahilc and oculovestibuar reflex in late 3rd nerve stage ( midbrain)?

Answer 40

Ipsilateral eye can’t move medially

Question 41

what is the motor responses at rest and to stimulation in late 3rd nerve stage ( midbrain)?

Answer 41

Decorticate or Decerebrate response