Vestibular System Flashcards
Vestibulo-ocular vs vestibulo-spinal reflex
- VO: when move head, helps EYES so don’t feel sick
- VS: helps maintain balance
vertigo: most common
BPPV
vertigo: lasts only seconds
BPPV
In BPPV, where does otoconia usually get discharged? where do they ultimately come to rest?
- posterior SSC
- lateral to cupula
vertigo: superior oblique on same side and superior rectus on opposite side affected –> eye spinning
BPPV
vertigo: characterized by vertigo and nystagmus that is associated with changes in head position
BPPV
vertigo: can follow head trauma, prolonged periods of bed rest, or unusual positions (ex. hair dresser getting hair washed)
BPPV
vertigo: idiopathic
BPPV
vertigo: most commonly occurs when turning over in bed, getting out of bed ( ), and when reaching up on a shelf with extension of neck ( )
BBPV
- malutinal vertigo
- top shelf vertigo
BPPV: a change in head position that promotes movement of the otoconia (away from/towards) the cupula establishes a gravity sensitive current, whereby hair cells within the cupula move (away from/towards) the kinocilium and (away from/toward) the utricle or ampulla
- away
- toward
- away
BPPV: for the vertical canals, movement produces depolarization and irritative response in the ( )
vestibular nerve
the nystagmus seen in BPPV is a form of ( ) nystagmus
peripheral
peripheral nystagmus (like in BPPV) are characterized by ( ) movements of the eyes in association with ( ) components that are often dysconjugate
- torsional
- upbeat or horizontal
peripheral form of nystagmus can be provoked by performance of the ( )
Hallpike-Dix maneuver
central nystagmus is characterized by eye movements that are often seen to be purely ( )
horzizontal, vertical, or torsional
BPPV: once nystagmus done after Epley maneuver, patient is instructed to do what?
sleep upright for 48 hours and to avoid sleeping on the proactive side for a total of 5 nights
Epley: complete circle movement of head gradually moves otoconia from long arm of posterior semicircular canal into the ( ), where it is dispersed
vestibule
vertiggo: second most common
Vestibular Neuritis
vertigo: aka acute peripheral vestibulopathy
vestibular neuritis
vertigo: inflammation occurs in nerve itself and not generally within vestibular ganglion
vesitbular neuritis
vertigo: patients develop severe rotational vertigo, often with nausea and vomitting
vestibular neuritis
vestibular neuritis: fast phase toward ( ) ear; slow phase toward ( ) ear
normal; abnormal
vertigo: last 2-3 days but up to weeks for full recovery
vestibular neuritis
what is vestibular neuritis often preceded by?
upper respiratory tract infection
how is vestibular neuritis treated?
meclizine or “zepam”s
vertigo: associated with hearing loss, tinnitus, and ear pressure/fullness
Meneire’s syndrome
vertigo: sudden falls after abrupt interruption in vestibulospinal tract followed by loss of postural tone in large antigravity muscles
Meniere’s syndrome
vertigo: lasts 2-24 hours
Meneire’s syndrome
in Meniere’s, do they lose high or low frequencies first?
low
Pike’s Peak
Meneire’s
vertigo: inner ear fluid imbalance on ECOG
meneire’s
vertigo: development of excessive endolymph within the labyrinth
meneiere’s
in meneire’s, periodic microruptures in layrinthine sac allow mixing of potassium rich ( ) with ( )
endolymph; perilymph
meneire’s: which nerve is located within the periymh and becomes hyperpolarized when exposed to endolymph?
8th nerve
how is meneire’s treated?
salt restriction, use of dieuretic agents, and weight loss (things that help you lose water)
how is ACUTE meneire’s treated?
vestibular suppresstants combined with antiemetics
phobic postural vertigo is a common cause of what?
dizziness
vertigo: patients complain of a subjective balance disturbance despite normal balance testing
phobic postural vertigo
vertigo: complaints include unsteadiness which is often associated with anxiety and vegetative symptoms
phobic postural
vertigo: associated with pereceptual stimuli (malls, bridges, stiars, social situations, etc)
phobic postural
OCD!
phobic postural
vertigo: 2/3 of patients will have complaints of dizziness at some point during disease
vertebrobasilar insufficiency
vertigo: 15-20% of patients with completed posterior circulation strokes will have had antecedent isolated attacks of dizziness
vertebrobasilar insufficiency
vertigo: sound drunk/slurring words
vertebrobasilar insufficiency
vertigo: ischemia within brain stem, cerebellum, or to inner ear labyrinth secondary to disease within the branches of the basilar artery
vertebrobasilar insufficiency
vertigo: typical attackes generally last on the order of minutes
vertebrobasilar insufficiency
when vertebrobasilar ischemia affects the brainstem and cerebellum, a broad diversity of associated neurological manifestations can occur such as:
- diplopia
- sensory changes
- ataxia
- dysarthic speech
- facial pain
- Horner’s syndrome
- weakness
- postural abnormalities
which vertigo is life threatening?
vertebrobasilar insufficiency
which are taking over conventional angiography as gold standard for assessing the anatomy of posterior vaculature (for vertebrobasilar insufficiency)?
MR angiography and MRI
alocohol changes the specific ( ) of endolymph within the cupula and can lead to nystagmus and vestibulopathy
gravity
alocohol have major effect on cerebellar function that can lead to ( )
- ataxia
- speech changes
- postural instability
- nystagmus
drug-induced vertigo: produce orthostatic hypotension
antihypertensive meds
drug-induced vertigo: produce cerebellar dysfunction
anticonvulsant agents
drug-induced vertigo: damage vestibular hair cells bilaterally, leading to gait instability and oscillopsia
antibiotics
one of the most ototoxic agents is ( ), which can produce profound vestibular dysfunction in some patients
gentamicin
patients with ( ) often have neurologic accompaniments. What are the most common? second most common?
migrane headache; visual distortions; vestibulopathy (typically vertigo)
in up to ( )% of patients with vestibular migraine, vertigo occurs completely independent of headage
30%
vertigo: connect perilymph with outside world
perilymphatic fistula
where do perilymphatic fistulas occur?
bw middle and inner ear at the oval or round windows
vertigo: causes include knocking brain, valsalva maneuver, vigorous exercise, stapes surgery, barotrauma, erosive lesions in petrous bone, inflammatory conditions such as syphilis and congenital conditions
perlympahtic fistula
vertigo: often develop hearing loss similar to Meneire’s
perlymphatic fistula
vertigo: hyperventilation-induced
perilymphatic fistula
vertigo: diagnostic- blow (insufflation) in ear –> vertigo
perilymphatic fistula
vertigo: patients with vertigo/nystagmus can be induced by what?
tragal compressions or swallowing
vertigo: treated with be rest, fluid hydration, keeping head elevated, avoid straining
perilymphatic fistula
vertigo is generally produced when injury occurs to ( )
one vestibular apparatus while the other remains intact (asymmetric involvement)
in peripheral vestibular dysfunction, slow phase goes toward lesioned eye bc?
the normal eye’s vestibular function is increased relative to abnormal eye
lightheadedness rasises concern about ( ), the mechanism of which most often involved ( )
- presyncope
- diffuse cerebral ischemia
orthostatic hypotension, cardia arrhythmias, certain metabolic derangements (like hypoglycemia, use of drugs with anticholinergic activity, and autoimmune dysfunction) can lead to what?
presyncope
what most commonly refers to the inability to maintain normal ambulation and upright posture?
disequilibrium
vegetative symptoms
diaphoresis (sweating), nausea, and vomiting
vegetative symptoms are often related to instability in ( ) located within floor of 4th ventricle (close to ventral vestibular apparatus)
autonomic centers
spatial disorientation: abnormalities are likely related to faulty sensory vestibular processing within the ( )
cortical vestibular areas
vestibular system has ( ), which travel through the brain stem to ( ) nuclues of thalamus on route to ultimate cortical traget projections
- ascending pathways
- contralateral ventral posterior lateral
what are accepted indications for performing brain imaging in patients with onset vertigo?
intracranial structural abnormalities (tumors and chiari malformation)
some patients who develop steriotypic paroysmal episodes of vertigo suffer from ( )
microvascular compression syndrome
vestibular seizures involve discharges from ( ) that produce symtpoms of vertigo and on occasion perception of environmental tilt
primary vestibular cortical zones
up to 20% of ( ) patients will experience vertigo at some time during illness
MS
when vertigo occurs secondary to inflammatory demylination due to MS, the lesions most commonly localize to the root entry zone od ( ) at the lateral pons, or at the level of the vestibular nucleus within medulla
CN 8
