oto vestibular and balance disorders Flashcards
What is the differential diagnosis of Ménière
disease.
Perilymphatic fistula, vestibular migraine, Cogan syndrome, autoimmune hearing loss, syphilis, mumps, Mondini mal-
formation
What percentage of patients with Ménière disease
will develop bilateral involvement?
Approximately 30%
What medical treatments are most commonly
used for symptomatic treatment of active Ménière
disease?
● Vestibular suppressants (e.g., benzodiazepines promethazine)
● Rest
● Potentially corticosteroids
What are the two most commonly used surgical
approaches for vestibular neurectomy?
● Middle fossa or the retrosigmoid approach
● Retrolabyrinthine and transmeatal approaches have also
been used.
How does the efficacy of endolymphatic shunt placement compare with endolymphatic sac decompression for treatment of Ménière disease?
No trials have clearly demonstrated superior results in one
treatment over the other.
Review the clinical presentation of Ménière
disease.
Low-frequency sensorineural hearing loss (SNHL, fluctuating and progressive), roaring tinnitus, aural fullness, and episodic vertigo generally lasting for hours
Describe Lermoyez syndrome.
Tinnitus and hearing loss that remit after an attack of vertigo
Define possible, probable, definite and certain
Ménière disease.
● Possible: Episodic vertigo without documented hearing
loss or SNHL (fluctuating or fixed) with dysequilibrium
but without definitive vertigo episodes; other causes
excluded
● Probable: One definitive episode of vertigo, audiometri-
cally documented hearing loss on at least one occasion,
tinnitus or aural fullness in the treated ear; other causes
excluded
● Definite: Two or more definitive spontaneous episodes of
vertigo lasting 20 minutes or longer, audiometrically
documented hearing loss on at least one occasion,
tinnitus or aural fullness in the treated ear, other causes
excluded
● Certain: Definite Ménière disease plus histopathologic
confirmation
Describe diet modifications for treatment of
Ménière disease.
● Avoidance of alcohol, caffeine, tobacco and monosodium
glutamate
● Adherence to a low-sodium diet (less than 1 to 2 g/day)
How is electrocochleography used in the diagnosis
of Ménière disease?
If the ratio of the summating potential, generated by the
organ of Corti, and the action potential, generated by the
auditory nerve, is elevated, diagnosis is indicated. A value
of 0.5 or greater is considered suggestive of Ménière
disease.
How is electrocochleography performed?
Neural responses to presented sounds are recorded
through an electrode in the middle ear (transtympanic
needle electrode), on the tympanic membrane, or on a gold
foil-wrapped earplug.
What is the role of intratympanic injections of
gentamicin in the treatment of Ménière disease?
● Selectively vestibulotoxic ablative treatment for unilateral
Ménière disease, often pursued after failure of more
conservative measures such as low-salt diet, caffeine
avoidance, diuretic therapy, and intratympanic steroid
injection
● Carries a 5 to 20% chance of significant SNHL
What is the role of intratympanic injections of corticosteroids in the treatment of Ménière dis-
ease?
These injections are onsidered a nonablative adjunct to
medical therapy that carries little risk of inducing hearing
loss. Subjects may experience a brief episode of vertigo
with injection if the steroid is not body temperature
and a low risk for persistent tympanic membrane
perforation.
When is a patient considered a candidate for
endolymphatic sac surgery?
Frequent vertiginous spells despite conservative treatment
in patients who are not candidates for ablative procedures
(bilateral disease, good residual hearing, contralateral
vestibular hypofunction)
What is the Donaldson line?
The Donaldson line is an imaginary line running parallel to
the plane of the lateral semicircular canal, extending
posteriorly and inferiorly through the center of the
posterior semicircular canal. The endolymphatic sac lies just
inferior to this line on the posterior fossa dura.
What pure tone audiometric findings can be seen in patients with superior semicircular canal dehiscence?
Conductive hyperacusis is sometimes seen, with bone
conductive thresholds occasionally less than 0-dB hearing
loss. This can lead to an air-bone gap even when air
conductive thresholds are within the normal range.
Describe the third window phenomenon.
The third window refers to a third opening in the inner ear,
in addition to the round and oval windows, that permits
pathological movement of perilymph within the labyrinth,
which may induce vertigo.
Describe the clinical presentation of superior
semicircular canal dehiscence syndrome.
Aural fullness, autophony, hearing loss (generally with an
air-bone gap and often supranormal bone conduction), and
dizziness often associated with loud sounds, exertion or
straining
How can one differentiate otosclerosis from superior semicircular canal dehiscence syndrome?
Patients with otosclerosis often have type AS tympanograms, diphasic or absent stapedial reflexes, and elevated to absent cervical vestibular evoked myogenic potentials. Patients with superior semicircular canal dehiscence will usually have normal stapedial reflexes, type A tympano- grams, and diminished vestibular evoked myogenic poten- tial thresholds (often < 70 dB).
How do you perform and interpret the Dix-
Hallpike test?
With the patient sitting, rotate the patient’s head by
approximately 45 degrees to the left or the right. The
patient then lies flat with the head slightly extended (~ 20
degrees). The eyes are then observed for ~ 45 seconds
looking for rotary nystagmus. If rotatory nystagmus occurs,
the test is positive. The direction of the fast phase reveals
the side that is affected.
Describe the clinical manifestation of benign
paroxysmal positional vertigo?
Short-lived (less than 60 seconds), room-spinning vertigo
provoked by head turn
