Monday, December 16, 2013

12/16/2013

12/16/2013

Answers:
What is the primary treatment of BPPV?
A) Semicircular Canal Occlusion 
B) Epley Maneuvers 
C) Diuretics 
D) Avoiding inciting head positions 
E) Vestibular Suppressants

80% of patients have resolution of symptoms with Epley or Semont maneuvers.


What are Ewald's three laws?

Ewald’s three laws:
1. A stimulation of the semicircular canal causes a movement of the eyes in the plane of the stimulated canal
2. In the horizontal semicircular canals, an ampullopetal endolymph movement cases a greater stimulation than an ampullofugal one.
3. In the vertical semicircular canals, the reverse is true.


MC Questions:
As a treatment for Meniere Disease, intratympanic --- is absorbed into inner ear primarily be ---- window and selectively damages vestibular hair cells.
A) Tobramycin; oval 
B) Tobramycin; round 
C) Gentamicin; oval 
D) Gentamicin; round 
E) Amikacin; oval 
F) Amikacin; round

Free Response Question:
What are the four symptoms of Meniere Disease?

Quick Facts:
Vestibular Neuronitis
-Third most common cause of peripheral vestibular vertigo (after BPPV and
Meniere)
-No gender bias, mostly in middle aged.
-<50% have antecedent viral illness.
-Presents w/ acute vertigo.
-Pathogenesis unknown.
-Treat w/ supportive care, MD job is to r/o central causes of acute vertigo
Pathogenesis
-Unknown
-May by viral infection, vascular occlusion or immunologic.
-Most likely is reactivation of latent HSV
Clinical Findings
-sudden onset vertigo w/ nausea and vomiting.
-normal hearing, normal neuro exam.
-May have postural instability towards injured ear but able to walk w/o
falling.
-No HA, has spontaneous nystagmus similar to acute peripheral vestibular
injury.
-Horizontal w/ torsional component, suppressed by visual fixation.
-reduction of vestibular signal in injured ear leads to relative vestibular
excitation in opposite ear = slow phase of nystagmus is toward injured ear and
fast phase is away from injured ear.
-nystagmus intensified be looking toward fast phase and decreased be looking
toward slow phase = “Alexander’s law”.
Imaging
-Get MRI to ID infarct/bleeding in pts w/ risk factors.
Special Tests
-Vestibular testing shows complete/reduced caloric response in injured ear.
-Will eventually normalize in 40% of patients.
Ddx
-Further eval only needed if concern for central because of acute vertigo does not
resolve in 48 hrs.
-Central causes for acute vertigo lasting days = stroke.
-Usually pt has other symptoms: diplopia, dysmetria, dysarthria, motor/sensory
deficits, abnormal reflexes, inability to walk w/o falling and central
nystagmus.
-Purely vertical or torsional nystagmus is highly suggestive of central
disorder.
Treatment
-Vestibular suppressant and antiemetics
-Withdraw these meds ASAP to avoid interfering w/central vestibular
compensation.
Prognosis
-Natural hx includes acute attack of vertigo lasting a few days w/ complete or partial
recovery within a few weeks/months.
-15% of pts have significant symptoms after 1 year.
-May later develop BPPV
-Vestibular rehab may help w/ residual symptoms

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