Acute Vertigo Flashcards
3 main symptoms of balance disorders?
- VERTIGO
o illusion of movement (usually rotational movement) - DIZZINESS
- UNSTEADINESS
2 forms of Vestibular Disorders?
- Peripheral
o affects the labyrinth & CN VIII
e.g. BPPV, Meniere’s disease - Central
o affects the CNS (i.e. BS & cerebellum)
e.g. stroke, MS and tumours
Classification of peripheral vestibular disorders?
o ACUTE (and does NOT stop)
- vestibular neuritis
- labyrinthine concussion
o INTERMITTENT
- BPPV (benign paroxysmal positional vertigo)
o RECURRENT (over long periods of time)
- Meniere’s disease (very rare)
- Migraine
o PROGRESSIVE
- acoustic neuroma - affecting CN VIII
Where do the vestibular projections go?
Go via. the thalamus to the temporo-parietal cortex
AND
regulate perception of motion in space
Unilateral lesion in terms of vertigo?
The tonus of the intact canal (SCC) gives a signal as if the head is rotating to the intact side
(as the other side has lost its intrinsic tone)
What can go wrong if inputs to the VOR go wrong?
Vesitbulo-ocular = nystagmus
Vestibulo-spinal = unsteadiness
Vestibulo-autonomic = nausea
Vestibulo-cortical = vertigo
Nystagmus?
Acute UNILATERAL vestibular disorder
The unopposed tone of the intact canal causes the eyes to be driven to the LESIONED side (VOR)
o movement detected by the brainstem
o tries to correct eye position via. fast movement
Effect minimised by visual suppression mechanisms
What should you look out clinically for VOR?
- Vestibular tone
- Lesion-induced asymmetry
- Visual suppression of nystagmus - VOR suppression
o Visual fixation can suppress PERIPHERAL nystagmus but can NOT suppress CENTRAL nystagmus - Vestibular compensation
BPPV?
Benign, Paroxysmal Positional Vertigo
o caused by otoconial debris in canals
o it is transient and provoked by head movement
o debris floating in the canals stimulates the ampulla causing false signals of head rotation = vertigo
o treated by vigorous head rotation to flush debris out
