Dizziness Flashcards
a distinct immediate and sometime incapacitating alteration of sensory experience characterized by a feeling of movement of oneself or environment
vertigo
unsteadiness or current tendency to stumble or fall, lacks a clear disturbance of sensorium of vertigo and related to ambulation
imbalance/disequilibrium
a floating feeling, mild unsteadiness or depersonalization
lightheadedness, can be replicated by hyperventilation
feeling faint or losing consciousness
presyncope
mechanics of the balance system
input from vestibular (angular and linear), proprioceptive, and visual -> cns -> eye and joints -> vestibulooccular reflex and vestibularspinal reflex
t/f dizziness occurs when there is any dysfunction in the visual, vestibular, or somatic (proprioceptive) system
true
non-vestibular causes of dizziness
cardiovascular, endocrine, neurologic, drugs
vestibular causes of dizziness
disruption in the afferent vestibular pathway or in the equilibrium reflexes mentioned earlier
how to diagnose dizziness
- ascertain if it’s truly vertigo
- elicit triggers, timing, duration, and intensity (detailed hx)
- detect associated symptoms (neuro pe)
- determine if vestibular or not
the first thing to do with a dizzy patient is __
determine if this is a neuro event (sudden onset headache and neurologic signs = urgent refer)
peripheral vs central vertigo
peripheral: membranous labyrinth/vestibular apparatus and vestibular nerve
central: nuclei and fiber tracts in cns
nystagmus in peripheral vertigo
- horizontal and torsional
- inhibited by fixating eyes
- fades after few days
- does not change direction with gaze
nystagmus in central vertigo
- purely vertical, horizontal or torsional
- not inhibited by fixation
- may last weeks to months
- may change direction with gaze towards fast phase
imbalance in peripheral and central vertigo
p: mild to moderate, can walk
c: severe, cannot walk or stand still
nausea/vomiting in p and c vertigo
p: severe
c: varies
hearing loss and tinnitus in p and c vertigo
p: common
c: rare
non-auditory neuro symptoms in p and c vertigo
p: rare
c: common
latency following provocation in p and c vertigo
p: longer (20 s)
c: shorter (5 s)
a conjugated, coordinated eye movement about a certain axis which can be divided into rhythmically alternating slow and fast phases
nystagmus
pathology in nystagmus
when only one vestibular system is sending inputs to the cns
kinds of movement in nystagmus
- horizontal
- vertical
- rotary
slow vs fast phase
slow: tonic eye movement induced physiologically or pathologically by vestibular stimulus
fast: saccade like re-fixation movement induced by oculomotor system
direction of the nystagmus is defined by the ____
fast component
pure tone audiometry
- confirms peripheral vertigo
- abnormal = mri
gold standard for diagnosis of retrocochlear pathology
mri
t/f the use of audiometric brainstem response is recommended for retrocochlear pathology
false, hx and pe enough
inflammation of the vestibular nerve
vestibular neuronitis/neuritis
pathophysio of vestibular neuritis
- sudden impairment of peripheral vestibular system of one side
- usually superior vestibular nerve
manifestation of vestibular neuritis
- 2 wks after urti
- sudden severe attack of rotary vertigo with no apparent cause
- horizontal symtpoms
vestibular neuritis pertinent negatives
no ear pain, hearing loss, or tinnitus
no other neuro impairments
no headache
in vestibular neuritis, nystagmus is heightened when ___ and decreased when ___
heightened when looking toward fast phase
decreased when looking toward slow phase (injured side)
ddx for vestibular neuritis
central infarction of cerebellum
vascular lesions
cns space occupying lesion
treatment for vestibular neuritis
supportive: bed rest, iv fluids, anti-vertigo meds, corticosteroids, vestibular rehabilitation after acute phase
prognosis of vestibular neuritis
good with complete recovery but elderly can have residual disequilibrium
most common cause of dizziness
benign paroxysmal positional vertigo
pathophysio of bppv
- caused by particles floating in endolymph of semicircular canal
- particles cause an unphysiologic deflection of cupula in scc (usually posterior scc)
manifestations of bppv
- brief episodic transient vertigo induced by rapid change in head movement
- vertigo and nystagmus <30 s
- bppv temporarily becomes less intense and disappears with repeated positioning
pertinent negatives in bppv
no ear pain, hearing loss or tinnitus
no other neuro impairments
diagnostics of bppv
dix haplike test: rotatory nystagmus after latent period of 10 s and lasts for a minute
pta-st and calorics normal
treatment for bppv
canalith repositioning maneuvers (epley’s maneuver and semont’s maneuver)
pathophysio of meniere’s disease
- hx: narrow vestibular aqueduct or previous hx of ear trauma
- oversecretion of endolymph = distention of cochlear duct and displacement of reissner’s membrane towards scala vestibuli
- rupture of reissner’s membrane = mixing of perilymph and endolymph = inc potassium in perilymph
clinical triad of meniere’s disease
fluctuating hearing loss, tinnitus, and vertigo
- tinnitus becomes louder, hearing becomes poorer
- vertigo ~20 mins
manifestation of meniere’s disease
- ear fullness
- hearing improves after attack but dysequilibrium persists
- pta: low tone sensorineural hearing loss
- vestibular testing: hypo- or hyperfunction and eventually hypofunction
treatment for meniere’s disease
- symptom control and decreasing fluid
- diuretics, ccb, histamine analogs
- anti-emetics
- salt restriction
- sedatives
- intratympanic injection of gentamicin or dexamethasone in serve cases
prognosis for meniere’s diesease
good but recurrent, hearing loss may become permanent
manifestation of migraine associated vertigo
- hx of migraine
- mimics bppv, meniere’s, or TIA
- diagnosis by exclusion
manifestations of cervicogenic vertigo
- headache
- syncope, tinnitus, nausea and vomiting, hearing loss, flashing lights
- elicited by cervical range of motion maneuvers
pathophysio of cervicogenic vertigo
- trigger: head/neck assumes a certain position or change in position
- misalignment causes abnormal information on orientation of head and neck
- brain mis-corrects based on wrong info = dizziness
diagnostics of cervicogenic vertigo
pta-st and caloric tests normal
neck ap-l: cervical spondylosis, degenerative change, straightening of normal cervical lordosis
treatment for cervicogenic vertigo
symptom control, rehab for cervical neck spine problem
examples for vestibular neuritis drugs
steroids: prednisone
examples of meniere’s drugs
diruetics: hydrochlorthiazide
histamine: betahistine
ccb: flunarizine, cinnarizine
examples of bppv drugs
histamine: betahistine
ccb: cinnarizine
examples of vestibular sedatives
benzodiazepines: diazepam, lorazepam
antihistamines, anticholinergic: meclizine, dimenhydrinate
anticholinergics: scopolamine
examples of antiemetics
metoclopramide: prochlorperazine
others: gingko biloba
