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Med Neuro Block 2 > Vestibular Disorders > Flashcards

Vestibular Disorders Flashcards

1
Q

What are the goals of otologic evaluation?

A
  • In the acute state: r/o stroke
  • Primary Goal: Is this otologic?
    • If otologic then which ear?
    • If can identify an ear, then which canal?
  • Develop a differential diagnosis
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2
Q

What are the types of dizziness?

A
  • Vertigo
    • Sensation of inappropriate movement
    • Spinning
    • lateral pulsion?
  • Disequilibrium / Imbalance
    • Unsteadiness
  • Lightheadedness / Giddiness
    • “wooziness”, disorientation, feeling “off”, faint
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3
Q
  • Vertigo is typically ________.
  • __________ is usually “ear” generated and causes a sensation of spinning
A
  • otologic
  • Nystagmus
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4
Q

Ewald’s First Law:

A

Stimulation of a semicircular canal generates eye movements in the plane of that canal

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5
Q

How are eye movements evoked by the stimulation of individual semicircular canals?

A
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6
Q

Nystagmus:

A
  • Opposite the direction evoked by canal excitation
  • Corrective mechanism
    • Rapidly bring eyes back to where they belong
  • Named for the fast direction of motion
    • Left / right; up / down
    • Rotary: clockwise / counterclockwise
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7
Q

What are ways to provoke a nystagmus?

A
  • Head Thrust Test
  • Gaze Evoked Nystagmus
  • Head Shake Test
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8
Q

Vestibular Ocular Reflex (VOR):

A
  • Most important vestibular reflex
  • Maintains eye position during motion
  • Extremely fast responses
  • Disturbances are demonstrated by eye examination
  • Eye movements that are inappropriate:
    • cause sensation of dizziness and nausea
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9
Q

Alexander’s Law:

A
  • Gaze in the direction of the fast phase of nystagmus increases amplitude and frequency
    • i.e. look to the stronger side
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10
Q

Ewald’s Second Law:

A

Excitatory responses for the angular VOR > inhibitory responses

  • Turning toward a side, activates that side greater than turning away from a side, inhibits that side
  • Activation/Inhibition close together add up
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11
Q

Head Shake Exam:

Which law is being exercised here?

A
  • Shake the patient’s head back and forth vigorously for 10-15 seconds
    • Make sure no neck problems
  • If one side is weak, the excitation on the stronger side will predominate
  • Eye movements will mimic unilateral canal excitation (fast beat to better side)

♦This demonstrates Ewald’s 2nd Law♦

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12
Q

Another way to generate eye movements to see which _____ and side are affected

A

canal

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13
Q

Superior Canal Dehiscence:

A
  • Loss of bone covering over the superior canal
  • Excitation by various stimuli:
    • Tones
    • Exercise
    • Pressure
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14
Q

Benign Paroxysmal Positional Vertigo (BPPV):

A
  • Posterior canal canalithiasis
  • Posterior canal activated by movement
    • Otoconia move in canal simulating movement
  • Nystagmus is toward affected ear and rotary in nature
    • Geotropic beating (toward the ground)
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15
Q

Name some vestibular disorders:

A
  • Labyrinthitis / Vestibular Neuronitis
  • Meniere’s Disease
  • Migraine
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16
Q

Labyrinthitis:

A
  • Loss of vestibular function in all canals
  • Can elicit signs of unilateral weakness
  • Hearing loss
  • Viral or bacterial in origin
    • Assess history of URI or otitis media
17
Q

Vestibular Neuronitis:

A
  • Superior Vestibular Nerve:
    • Horizontal and superior canals
    • Posterior canal spared (BPPV)
  • Acute Phase:
    • Nystagmus beating away from affected ear
  • Chronic Phase:
    • Loss of unilateral VOR
    • Head thrust; head shake; calorics
18
Q

Vestibular Neuronitis:

Acute Phase

A
  • 1st week
  • Sudden and intense vertigo and imbalance
  • Need to stay still
  • Nausea and vomiting
  • Typically seen in ER
19
Q

Vestibular Neuronitis:

Sub-acute Phase

A
  • 1-6 months
  • Episodic vertigo
    • Short, less intense episodes
  • Motion sensitivity
  • Gradual improvement in balance
20
Q

Vestibular Neuronitis:

Chronic Phase

A
  • > 6 months after initial attack
  • Weakness in balance function on one side
  • Sensitive to rapid head movements
  • Rare to have recurrence of initial attack
  • May develop BPPV
  • 30% develop anxiety/”fear of dizziness”
21
Q

Meniere’s Disease:

A
  1. Inner ear fluid imbalance
  2. Episodic vertigo
  3. Fluctuating hearing loss
  • Entire labyrinth affected
  • Usually unilateral so should be able to elicit unilateral signs
    • Head shake
    • Head thrust
22
Q

Meniere’s Disease:
Episodic Vertigo

A
  • Recurrent and episodic
  • Vertigo
  • Last 30 minutes to ~4 hours
  • Minimal imbalance between attacks
  • Unilateral balance weakness
    • fast turns or head rotations
23
Q

Meniere’s Disease:
Fluctuating Hearing

A
  • Low frequency
  • One ear
  • Lasts minutes to weeks to months
  • Can become permanent
  • May respond to steroids
24
Q

Meniere’s Disease:
Associated Symptoms

A
  • Tinnitus:
    • Low-frequency, rumble, hummmm
    • Worsens before attacks; better after
  • Aural fullness:
    • One sided pressure
    • Worsens before attacks; better after
25
Q
  1. Which disease has a long vertgio and hearing loss?
  2. Which disease has a short vertgio and hearing loss?
  3. Which disease has a long vertgio and no hearing loss?
  4. Which disease has a short vertgio and no hearing loss?
A
  1. Labyrinthitis
  2. Meniere’s Disease
  3. Vestibular Neuronitis
  4. Benign Paroxysmal Positional Vertigo (BPPV)
26
Q

Vestibular symptoms are more common in patients suffering from migraine with _____.

A

aura

27
Q

Vestibular Migraine:

Veritgo

A
  1. Spontaneous vertigo including:
    • **Internal vertigo: **a false sensation of self-motion
    • External vertigo: a false sensation that the visual surround is spinning or flowing
  2. **Positional vertigo: **
    • occurring after a change in head position (but not specific like BPPV)
  3. Visually induced vertigo:
    • triggered by complex or large moving visual stimulus
  4. Head motion induced vertigo:
    • occurring during head motion
28
Q

Vestibular Migraine:
Duration

A
  • Episode length
    • 30% lasting minutes
    • 30% lasting hours
    • 30% several days
    • 10% seconds (mostly related to head movement or visual stimuli)
  • Note: some patients may take weeks to fully recover from an episode
29
Q

Question: If I stimulate the right horizontal canal (ex: warm caloric on the right), I will see nystagmus that beats:

  1. Horizontal to the left
  2. Horizontal to the right
  3. Rotary to the left
  4. Rotary to the right
A

Answer:

  1. Horizontal to the right
  • Beats in the plane of the stimulated canal
  • Beats toward the more active side
  • Ewald’s 1st Law
30
Q

Question: My 3 days post-op left acoustic neuroma patient (left nerve was cut) no longer has visible nystagmus. I can bring out the nystagmus by having them look to the:

  1. Left
  2. Right
  3. Up
  4. I can’t bring out nystagmus
A

Answer:

  1. Right
  • Has left hypofunction due to cutting nerve at surgery
  • Nystagmus beats to stronger side (i.e., the right)
  • Alexander says look to stronger side and increase nystagmus
31
Q

Question: My left acoustic neuroma patient is seen 1 month post-op. If I do a head shake exam I will see nystagmus beating to the:

  1. Left
  2. Right
  3. Up
  4. There will be no nystagmus
A

Answer:

  1. Right
  • Left is permanently weak
  • Will beat toward stronger side (forever)
32
Q

Question: I suspect vestibular neuritis in a patient with a single long vertigo attack 1 year ago. To identify a unilateral vestibular weakness and which ear was affected, my exam should include:

  1. Head thrust test
  2. Head shake exam
  3. Both A and B
A

Answer:

  1. Both A and B
  • Head thrust may show refixation saccades with thrust to the weak ear
  • Head shake should uncover asymmetry with nystagmus beating to the good ear (away from the affected ear)

Med Neuro Block 2 (13 decks)

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