Clinical correlation: COMA Flashcards
what is normal oculocephalic testing?
when you turn your head the eyes move conjugately to the opposite direction
what are the 4 levels of conciousness?
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
when would you get a cheyne-stokes respiratory pattern?
in lesion of the diencephalon ( includes the thalamus)
how would you characterize the cheyne stokes breathing pattern?
waxing and waning, person could even stop breathing
what is central neurogenic hyperventilation is characterized by what?
really fast breathing
a lesion where causes central neurogenic hyperventilation?
reticular activating system in the midbrain above the colliculus essentially cutting off the brainstem and diaphragm from the breathing center causing abnormal breathing
a lesion where causes aPneustic respiration?
a lesion in the Pontine tegmentum (mid pons breathing centers) thus only the medulla breathing center is left
how would you characterize apneustic respiration?
inspiratory spasms
how would you characterize ataxic breathing?
characterized by complete irregularity of breathing, with irregular pauses and increasing periods of apnea
how does pt present and what is lesioned in a tectal pupillary light reflex?
large fixed pupils, w/ no reaction to light,
isolated lesion in tectum
how does pt present and what is lesioned in a pinpoint pupillary light reflex?
isolated lesion in the pons sympathetics impaired so can’t dilate
where is the lesion if a patient has midposition fixed dilated pupil and is in a coma?
the midbrain
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?
III Nerve lesion (uncal)
what would occur during pupillary reflex in a diencepahlic lesion?
the pupils will be small and reactive
what occurs in a metabolic pupillary reflex?
the eyes are small and reactive and there is a lesion in the tectum of the midbrain ( starting to lose some of the sympathetics.
what does the occularvestibular facilitate?
it facilitates eye movement in the opposite direction of head movement.
describe how the occulovestibular reflex works.
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.
what is decorticate posturing?
(Spastic hemiparesis)
lesion above the red nucleus of the midbrain
- arm, wrist, finger flexion, adduction of upper extremity
- leg extension, internal rotation, plantar flexion
what is decerebrate posturing?
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
the _________ ___________ system in the _______ keeps awake. and we only need one side for consciousness
reticular activiating system in the midbrain
what is the respiratory pattern in bilateral midbrain stage?
sustained regular hyperventilation ( occurs because only the lower respiratory centers are working).
what is the pupillary size and reaction in bilateral midbrain stage?
Irregular, no pupillary constriction
what is the oculocepahilc and oculovestibuar reflex in the bilateral midbrain stage?
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
what is the motor responses at rest and to stimulation in bilateral midbrain stage?
Motionless or bilateral ( but mostly on the contralateral side of the lesion) Decerebrate posturing upon stimulation( i.e trying to arouse them)
