Brainstem Disorders Flashcards
what is involved in a MEDIAL BS lesion?
motor tracts
MLF
medial lemniscus
motor nuclei (divide into 12)
- CN 3, 4, 6, 12
what is involved in a LATERAL (side) BS lesion?
sympathetic (hypothalamospinal) tract -Horner’s syndrome
spinothalamic tract
spinocerebellar tract
sensory nuclei (don’t divide into 12)
- CN 5, 7, 8, 9, 10
if there is a lesion to the lateral corticospinal tract or DCML above the caudal medulla, where is the loss? why?
contralateral signs bc the damage is after the decussation
if there is a lesion to the lateral cortiocospinal tract or DCML below the caudal medulla, where is the loss? why?
ipsilateral signs bc the damage is b4 the decussation
if there is any BS damage to the spinothalamic tract, where is the loss? why?
contralateral signs bc of the immediate decussation so damage is after decussation
if there is a lesion of the L rostral anteromedial medulla, what is the loss?
paresis of the R hand and foot
loss of light touch and proprioception on the R side of the body
paresis on the L side of the tongue
how do you differentiate the involvement of the motor tract or the motor cranial neurons?
ask the pt to close their eyes
hypertonicity vs hypotonicity
what supplies blood to the midbrain?
posterior cerebral artery
basilar artery
what supplies blood to the pons?
anterior inferior cerebellar artery (AICA)
basilar artery
what supplies blood to the medulla?
posterior inferior cerebellar artery (PICA)
vertebral artery
anterior spinal artery
what are the cardinal signs of BS dysfxn? (KNOW THIS)
the 4 Ds:
1) dysphagia
2) dysarthria
3) diploplia
4) dysmetria
disorders of vital fxns
disorders of consciousness
why does BS dysfxn cause dysphagia and dysarthria?
the CNs are in the pons and medulla of the BS
why does BS dysfxn lead to diploplia?
CN 3, 4, 6 control eye movement and they are in the BS
damage to what structure in the BS can cause disorders of consciousness?
reticular formation
what is vertebrobasilar artery insufficiency?
causes transient symptoms of BS ischemia reproduced with cervical extension and rotation
vertebrobasilar artery insufficiency is characterized by poor blood flow to what part of the brain?
the posterior brain
what are the symptoms associated with BS ischemia?
abrupt onset of neurologic symptoms (dizziness, weakness, incoordination, and somatosensory dysfxn)
sustained ischemia=Wallenberg syndrome, loss of consciousness
what is the most common BS stroke?
Wallenburg syndrome
lateral medullary lesion
what is Wallenburg syndrome?
a LATERAL medullary lesion
PICA affected
very parasympathetic
spinal trigeminal tract: loss of nociception and temp from the ipsilateral face
spinothalamic tract: loss of nociception and temp from contralateral body
spinocerebellar tract: ipsilateral ataxia
descending sympathetic tract: ipsilateral Horner’s syndrome
does Wallenburg have contra or ipsi s/s?
both
what CNs are involved in Wallenburg syndrome?
5, 7, 8, 9, 10, 12
what are the CN s/s associated with Wallenburg syndrome?
vertigo, nystagmus, problems swallowing and speaking, hoarse voice, digestion issues, inability to slow the HR
what CNs are involved in AICA syndrome?
5, 7, 8
what is AICA syndrome
lateral caudal pons lesion
AICA affected
spinal trigeminal tract: loss of nociception and temp from the ipsilateral face
spinothalamic tract: loss of nociception and temp from contralateral body
spinocerebellar tract: ipsilateral ataxia
descending sympathetic tract: ipsilateral Horner’s syndrome
what is the 2nd most common BS stroke?
lateral caudal pons lesion
are the s/s of AICA syndrome ipsi or contra?
both
what are the CN s/s associated with AICA syndrome?
loss of efferent limb of corneal reflex and stapedius reflex (sounds are louder), lack of tears and salivation, unilateral deafness, vertigo, nystagmus, nausea, vomiting
what is an anteromedial midbrain stroke?
the most common midbrain stroke
involved the basilar artery
contra signs (except CN 3)
med lemniscus: contra loss of sensation
red nucleus: motor dysfxn obscured by ataxia; pathologic laughing/crying
motor tracts (corticopontine): contra cerebellar ataxia; (corticospinal and corticobrainstem): contra paresis of the body and lower face
MLF: internuclear opthalmoplegia obscured by CN 3 lesion
what is internuclear opthalmoplegia?
damaged connection bw CN 6 and 3
what CNs are involved in anteromedial midbrain stroke?
3
what are the CN signs associated with an anteromedial midbrain stroke?
pupil dilation from lack of pupillary sphincter innervation
inability to focus on near objects
unable to move eye up, down, or in
double vision
what structures may be involved in disorders of consciousness?
cerebrum (thalamic or hypothalamic) and BS (reticular formation)
what is a coma?
unarousable state
no response to strong stim
lost vital fxns (vent is necessary)
what is a vegetative state?
cycle of sleeping and waking (can yawn and vocalize)
unresponsive wakeful state
complete loss of consciousness w/o alteration of vital fxns (don’t need a vent)
what is a minimally conscious state?
respond to very painful stim and follow very easy instructions
some signs of consciousness
in and out of consciousness
tumors in the cerebellum or BS cause an increase in what?
intracranial pressure
what are the symptoms associated with increased ICP?
headache, nausea, vomiting, CN dysfxn, and/or hydrocephalus
possible ataxia
what is the most common BS tumor?
acoustic neuroma
what is an acoustic neuroma?
a benign tumor of the Schwann cells surrounding CN 8
unilateral vestibular lesion
