Studied by 0 people
I still need to condense this one lol
A generalized whirling sensation in the head associated with light headedness, near-fainting feeling, floating sensation, and confusion is known as _______
dizziness
What are possible causes of dizziness?
presyncope or postural hypotension
disequilibrium associated with aging
hyperventilation
cardiac arrhythmia
carotid sinus hypersensitivity
anemia
endocrine disorders
psychogenic- anxiety, panic, phobia
Dizziness w/ a sense of rotation of self or environment due to a distortion/mismatch of vestibular, visual and somatosensory inputs from a disturbance of vestibular system or central connections is known as _____
vertigo
What type of vertigo?
sudden onset
often with N/V
tinnitus and hearing loss
horizontal nystagmus that should lessen when gaze is focused
peripheral vestibulopathy
What type of vertigo?
more gradual progression
vertical nystagmus
MRIs are helpful
central origin
What are causes of vertigo?
sensory distortion - cataracts
motion sickness
labyrinth disorders - bacterial/viral infx
vestibular nerve inflammation - herpes
cerebellopontine angle tumor
brainstem and cerebellum dz - infarct
cerebral hemisphere and connections - seizures
other CNS/PNS disorders - demyelinating dz, migraines, cervical spine dz
systemic and metabolic disorders - anemia, intoxication
How is vertigo evaluated?
Dix Hallpike maneuver, assess Roberg, gait, nystagmus
audiologic testing, MRI, CT (indicated w/ persistent sx and suspected CNS dz)
What is the treatment for vertigo?
symptomatic - meclizine, scopolamine
What historical factors are considered concerning?
ataxia (incoordination of limbs or gait)
dysarthria (inability to articulate)
dysphasia (lack of coordination of speech → implies cortical damage)
diplopia
sudden vertigo
“Overshoot” when the limb is directed at a target is known as _____
terminal dysmetria
A tremor as the limb approaches a target is known as ______
terminal intention tremor
Stimulation of the semicircular canals may produce ______
nystagmus
Dix Hallpike for positional nystagmus
Peripheral Disorder | Central Disorder | |
Latent period before onset of positional nystagmus | 2 to 20 seconds | None |
Duration of Nystagmus | < 1 minute | > 1 minute |
Fatiguability | Fatiguing with repetition | No fatiguing |
Direction of Nystagmus | Only one type, usually rotary | May change direction with a given head position |
Intensity of Vertigo | Severe | Less severe, sometimes none |
What kind of testing is this?
evaluates disorders of vestibule-ocular pathways
stimulating labyrinth causes vertigo and nystagmus if nerve pathways intact
Pt supine, head elevated 30 deg, 50ml ice cold water instilled into ear canal
caloric testing
What is a normal response to caloric testing?
stimulation produces nystagmus w/in 30s
What response to caloric testing would be seen in a patient w/ unilateral vestibular dysfunction?
irrigation of affected side fails to cause nystagmus
What response to caloric testing would you see in an unconscious patient w/ brainstem reflexes intact?
eyes deviate toward irrigated ear
What kind of disorder?
lesion outside brain
sudden onset vertigo lasting up to a few days
intense vertigo sx marked exacerbation by head movement
intermittent sx, lasts for brief periods
produces significant distress
no neuro exam findings
peripheral disorders
what kind of disorder?
lesion w/in brain
ataxia, vertigo, nystagmus
sx presently slowly over several mos
little or no change in sx w/ head movement
may have other focal neurological signs
central disorders
What condition?
sudden attacks of rotational vertigo triggered by certain head moments (getting out of bed or laying down)
d/t otolithic material in semicircular canal
fully resolves b/t episodes
dx w/ dix hallpike
benign paroxysmal positional vertigo (BPPV)
What is the treatment for BPPV?
epley maneuver - dislodge otolith from canal
meclizine 25mg PI q4-6h PRN
scopolamine patch 0.5mg QD
What condition?
common cause of dizziness originating in inner ear
endolymphatic hydrops; progressive sensorineural hearing loss
dix hallpike- nystagmus
most often only one ear involved
onset typically age 20-50
Meniere’s Disease
What is the tetrad of menieres disease?
vertigo, hearing loss, tinnitus, aural pressure
What are clinical findings of meniere’s disease?
acute episodic
horizontal and/or rotary nystagmus
hearing loss
audiometry → low frequency pure tone loss +/- impaired speech discrimination and inc sensitivity to loud sounds
vertigo resolves as hearing loss worsens
majority middle aged pts stabilize on own
what is the treatment for menieres disease?
goal → lower endolymphatic pressure
low Na diet (< 2 g/day)
diuretics (HCTZ, acetazolamide)
meclizine or scopolamine for acute episodes
surgery if persistent, disabling, or drug resistant
what condition?
benign tumor that arises from sheath of CN VIII in internal auditory canal
presents w/ insidious onset hearing loss, tinnitus, HA, vertigo, facial weakness
unilateral sensorineural hearing loss on exam
acoustic neuroma
what is the best diagnostic study for acoustic neuromas?
MRI w/ constrast
What is the treatment for acoustic neuromas?
surgical excision- translabyrinthine surgery, craniectomy
(good prognosis)
What medications are ototoxic?
aminoglycosides & salicylates (ASA)
which aminoglycoside is the worst offender of ototoxicity?
gentamicin
How does alcohol intoxication affect the vestibular system?
makes it unusually sensitive to gravity and position (peripheral system)
What sx are you likely to see after ingesting alcohol?
positional vertigo w/in 2 hrs
vertigo and nystagmus, accentuated when eyes closed
other cerebellar/central sx → dysarthria, gait ataxia, somnolence
What causes wernicke’s encephalopathy?
thiamine deficiency
In what patient population is wernicke’s encephalopathy especially prevalent?
alcoholics
What is the classic triad of wernicke’s encephalopathy?
gait ataxia, ophthalmoplegia, confusion
what should all patients w/ undiagnosed altered mental status, oculomotor disorders, or ataxia receive?
parenteral thiamine
What is the treatment for Wernicke’s Encephalopathy?
resolves w/ administration of thiamine 100mg IV (give BEFORE glucose)
What symptoms of WE may not be fully reversible?
ataxia, learning and memory deficits
Years of alcohol abuse causes ______
alcoholic cerebellar degeneration
toxic degeneration of Purkinje cells
evolves gradually
gait ataxia, tremor
nystagmus absent
cognition intact
irreversible even w/ abstinence
What symptom is seen in MS ~10% of the time?
vertigo
What might an occlusion of cerebellar artery cause?
dizziness or vertigo; may result in cerebellar infarction
what is the most common cerebellar ataxia?
friedreich’s ataxia
what condition?
various inherited disorders cause atrophy of cerebellum, brainstem, spinal cord
slurring dysarthria, gait ataxia, nystagmus
vertigo usually absent
ex: Friedrichs, spinocerebellar
cerebellar ataxias
what condition?
autosomal recessive inheritance; chromosome 9
usually presents before 25 (5-15 y/o'clock)
pathological changes in posterior columns, lateral corticospinal tracts and peripheral nerves
spinal cord becomes thinner, myelin sheath destroyed, distal axons degenerate
brain, cerebellum, brainstem relatively unaffected
gait ataxia first, progresses to arms
sensory loss and weakness later findings
friedreichs ataxia
what are clinical findings of friedreichs ataxia?
lower limb reflexes absent
sensory loss prominent → joint position and vibration senses impaired
positive romberg
muscle atrophy
progressive kyphoscoliosis, clubfoot
NCV: slowed conduction
echo: cardiomyopathy
progression to wheelchair bound in 10-20 years
cardiomyopathy, myocardial fibrosis, heart block possible
death in early 30s
What are examples of cerebellar tumors?
metastases often from lung or breast
astrocytoma- surgical resection possible
medulloblastoma- highly malignant, often presents in childhood
