15. Dizziness and Vertigo Flashcards
Acute vestibular syndrome defn
dizziness acute, constant, persists >day, accompanied by n/v, unsteady gait, nystagmus and interolance to head motion
What 3 systems are key for equilibrium and awareness of body in relationship to surrounding sx
visual
proprioceptive
vestibular systems
What does the vestibular apparatus do?
maintain head position
stabilize head movement
What is the vestibular apparatus made up of?
three semicircular canals and two otholithic structures
Semicircular canal info
info about movement and angular momentum
Utricle info
head tilt and vertical linear accel
How to otoliths move in BPPV
freely moving otoliths that are inappropriately located within the semicir- cular canals, as in BPPV, can produce positional vertigo even when the head is currently still if the head had been recently moved.
impulse travel from vestibular apparatus to brainstem and cerebellum
acoustic nerve (cranial nerve [CN] VIII), enter the brainstem just below the pons and anterior to the cerebellum, and proceed to the four vestibular nuclei of the brainstem and to the cerebellum
From brainstem and cerebellum, impulses travel along which 2 pathways to cause vertigo?
1) MLF
2) vestibulospinal tract
When does nystagmus occur?
when syncronhized vestibular info becomes unbalanced
Typically, it results from unilateral vestibular dis- ease, which causes asymmetric stimulation of the medial and lateral rectus muscles of the eye. This unopposed activity causes a slow move- ment of the eyes toward the side of the stimulus, regardless of the direc- tion of deviation of the eyes. The cerebral cortex then corrects for these eye movements and rapidly brings the eyes back to the midline, only to have the process repeated.
By convention, the direction of nystagmus is denoted by the direction of the ?“cortical” component.
fast
Vertebrobasilar insufficiency defn
emporary set of symptoms due to ischemia in the posterior circulation of the brain, which supplies the medulla, pons, midbrain, and cerebellum. M
BPPV pathophysiology
Otoliths inappropriately displaced from utricle into semicircular canals (posterior > horizontal > anterior)
Vestibular neuritis and labrynthitis pathophys
inflamm/possibly viral of vestibular nerve
Meniere disease pathophys
endolymphatic hydrops/excess endolymph in inne ear
Perilymph fistula pathophys
abnormal opening btwn middle and inner ear
DDX peripheral vertigo
bppv
vestibular neuritis and labrynthitis
meniere disease
perilymph fistula
DDX of dizziness into 3 categories - what are they?
acute severe - vestibular neuritis, stroke
recurrent attacks: Meiniere, tia
recurrent positional: bppv, cerebellar tumor, ms
ddx timing and triggers approach 3 categories -defn
- ac vestibular: bestibular neuritis, cerebellar stroke
- spont episodic vestibular syndrome - meniere disease, vbi
- triggered episodic vestibular syndrome - bppv
vertigo defn
spining sens
triad meniere disease
hearing loss
vertigo
tinnitus
Peripheral causes of vertigo - list 8
Benign paroxysmal positional vertigo (BPPV) Vestibular neuritis (or neuronitis)/labyrinthitis Ménière disease
Foreign body in ear canal
Acute otitis media Perilymphatic fistula
Trauma (labyrinth concussion) Motion sickness
Acoustic neuroma
central causes of vertigo
Vertebral basilar artery insufficiency Cerebellar hemorrhage or infarction Tumor
Migrainous vertigo
Multiple sclerosis
Posttraumatic injury (temporal bone fracture, postconcussive syndrome) Infection (encephalitis, meningitis, brain abscess)
Temporal lobe epilepsy
Subclavian steal syndrome
BPPV hx
Short-lived (typically <30 s), positional, fatigable episodes; more often in older adults.
Name 5 medications causing vestibulotoxicity
(e.g., aminogly- cosides, anticonvulsants, alcohols, quinine, quinidine, and minocy- cline