Vertigo Flashcards
A patient with Meniere’s disease has been disabled for > 1 year and is on disability. What functional level is he/she
6
What % of patients with Meniere’s disease do not respond adequately to salt restriction and diuretics
1 O%.
What is the treatment for otosyphilis
2.4 million U of benzathine penicillin IM q week for at least 3 weeks (up to I year) or I 0 million U of penicillin G IV qd for 10 days followed by 2.4 million U of I M benzathine penicillin q week for 2 weeks plus prednisone 40 - 60 mg qd for 2 - 4 weeks followed by a taper.
What % of patients with classic migraine experience vertigo
30 - 40%.
What is the rate of recurrence
30 - 50% eventually have a recurrence; 10 - 20% within I - 2 weeks of the maneuver.
What happens to the SP in the presence of hydrops
36% of patients will have a normal SP~ 32% will have a moderately enhanced negative SP; 27% will have a very enhanced negative SP; 5% will have no SP or action potential.
What % of patients with hearing loss secondary to otosyphilis improve with penicillin and steroid therapy
3I %.
A patient with Meniere’s disease is able to work, drive, and travel but must exert a great deal of effort to do so and is “barely making it.” What functional level is he/she
4 (out of 6).
After aminoglycoside treatments, when is the usual onset of dysequilibrium
4 days after treatment.
What is the success rate of the Epley maneuver after only 1 manipulation
50 -77%.
What % of patients will have improved tinnitus and hearing after endolymphatic sac surgery
50°/o experience improvement in tinnitus and 30 - 40% experience improvement in hearing.
What % of patients with vertigo secondary to otosyphilis improve with penicillin and steroid therapy
58 - 86%.
What % of patients have improvement of vertigo after endolymphatic sac surgery
70°/o experience complete relief, 20% experience decreased vertigo.
What is the success rate of singular neurectomy
79-94%.
What is the success rate after 2 manipulations
95 - 97%.
What are the most common manifestations of VBI
Abrupt, transient attacks of vertigo associated with bilaterally reduced caloric responses.
What is the treatment for this syndrome
Acetazolamide.
What 3 variables does it measure
Action potential (AP), summating potential (SP), and cochlear microphonic (CM).
What % of patients have bilateral Meniere’s disease
After 2 years, 15% of patients; after I 0 years, 25 - 35%; and after 20 years, 40 - 60°/o.
Which aminoglycosides are primarily cochleotoxic
Amikacin, dihydrostreptomycin, kanamycin, and streptomycin at high doses.
What disorders are associated with down-beating nystagmus
Amold-Chiari, cerebellar degeneration, multiple sclerosis, brainstem infarction, lithium intoxication, magnesium and thiamine deficiency.
Where is the endolymphatic sac
Anterior to Trautmann’s triangle within the dura, medial and inferior to the posterior semicircular canal.
Which way is the sigmoid sinus retracted in the retrosigmoid approach to vestibular nerve section
Anteriorly.
What is the treatment for vertigo secondary to VBI
Aspirin or ticlid if aspirin-sensitive.
What disorders are associated with bidirectional gaze-fixation nystagmus
Barbiturate, phenytoin, and alcohol intoxication.
What region of the inner ear is most susceptible to permanent loss of hair cells
Basal turn of the cochlea.
What are the most widely used agents for prophylaxis of migraine
Beta-blockers and calcium antagonists.
How do aminoglycosides exert their toxic effects on the hair cells of the inner ear
Bind to the plasma membrane and displace calcium and magnesium; once transported into the cell, bind with phosphatidylinositol, causing disruption of the plasma membrane and inhibition of inositol triphosphate, resulting in cell death.
Which of these is superior in complete elimination of vertigo
Both are equally effective.
What disorders are associated with up-beating nystagmus
Brainstem tumors, congenital abnormalities, multiple sclerosis, hemangiomas, vascular lesions, encephalitis, and brainstem abscess.
What are the deposits thought to consist of
Calcium carbonate crystals, possibly resulting from microfractures of the temporal bone near the round window niche (also near the ampulla of the posterior SCC).
Which theory is currently more favored
Canalolithiasis.
What features distinguish BPPV from vertigo due to CNS disease
CNS disease: no latent period, direction of nystagmus varies, nystagmus and vertigo are nonfatiguable.
What are the criteria for “possible” Meniere’s disease
Cochlear or vestibular variants of Meniere’s for which other causes have been excluded.
What are the 2 main theories of the pathophysiology of BPPV
Cupulolithiasis theory: deposits gravitate, attach to, and stimulate the cupula. Canalolithiasis theory: deposits float freely within the semicircular canals (SCC) under the influence of gravity.
What happens to the SP when the basilar membrane is displaced towards the scala media
Decreases or reverses polarity.
How does this theory account for the latency of onset of nystagmus
Delay is due to the adherence of deposits to the membranous wall of the labyrinth.
What happens to CM in the presence of hydrops
Diminishes; after-ringing may occur.
What clinical findings are diagnostic of central vestibular disorders
Disconjugate eye movements, skew deviation, vertical gaze palsy, inverted Bell’s phenomenon, seesaw nystagmus, bidirectional nystagmus, periodic alternating nystagmus, and nystagmus that is greater with eyes open and fixed on a visual target than in darkness.
What is the mainstay of treatment for Meniere’s disease
Diuretics and dietary salt restriction.
What increases the likelihood of headaches after the retrosigmoid approach
Drilling out of the medial portion of the lAC.
What are the surgical options for treatment of Meniere’s
Endolymphatic shunt, destructive labyrinthectomy, and vestibular nerve section.
Which of these is the only surgical procedure considered in an only-hearing ear
Endolymphatic shunt.
Which of these is most commonly performed
Endolymphatic shunt.
What therapeutic maneuver is based on the canalolithiasis theory
Epley.
What are the most widely used agents for treatment of acute migraine
Ergotamine tartrate and sumatriptan.
What is the primary problem of IM penicillin therapy for otosyphilis
Fails to achieve treponemicidal levels in the CSF.
What syndrome is characterized by recurrent episodes of vertigo and ataxia in several members of a family
Familial ataxia syndrome.
What is the Jarisch-Herxheimer reaction
Fever and flu-like symptoms beginning within 4 hours of commencing treatment for secondary syphilis.
What is the success rate of vestibular nerve section
For the middle fossa approach, complete elimination of vertigo is achieved in >90%; for the posterior approaches, complete elimination of vertigo is achieved in >80%.
Which aminoglycosides are primarily vestibulotoxic
Gentamicin and streptomycin.
What is the glycerol test for Meniere’s
Glycerol given orally increases the serum osmolality, causing a shift of water and electrolytes from the perilymph and CSF to the serum, and increases cochlear blood flow. In most patients with Meniere’s, this will result in an improvement in hearing.
What are the landmarks for identification of the lAC during middle fossa approach to vestibular nerve section
Greater superficial petrosal nerve, malleus head, and superior SCC.
What is the incidence of total SNHL after endolymphatic sac surgery
I - 2%.
What are the clinical features of BPPV
I 0-20 second attacks of rotational vertigo, precipitated by head movements, with spontaneous resolution after several weeks to months in 80-90%.
According to AAO-HNS, what are the criteria for “definite” Meniere’s disease
I) 2 or more episodes of spontaneous rotational vertigo lasting 20 minutes or longer. 2) Audiometrically documented hearing loss on at least one occasion. 3) Tinnitus or aural fullness in the affected ear. 4) Exclusion of other causes.
How is ECochG helpful prior to destructive surgery for Meniere’s disease
In patients with unilateral disease, abnormalities in the asymptomatic ear (SP:AP >35°/o, distorted CM with after-ringing) predict development of hydrops in that ear.
What are the indications for surgical treatment of BPPV
Incapacitating symptoms > 1 year, confirmation of BPPV with Dix-Hallpike on at least 3 visits, failure of conservative treatment, normal head M Rl.
What happens to the SP when the pressure increases inside the scala media
Increases (basilar membrane is displaced towards the scala tympani).
What is the significance of a positive test
Indicates hydrops, which can be caused by Meniere’s, late syphilis, Cogan’s disease, otosclerosis, or acoustic neuroma.
What portion of the Vlllth nerve is sectioned in vestibular nerve section
Lateral portion (superior and inferior vestibular nerves) in the lAC.
What do the utricle and saccule detect
Linear acceleration.
What are the metabolic effects of prolonged thiazide diuretic therapy
Metabolic alkalosis with hypokalemia and hypochloremia, hyperglycemia.
What are the 4 primary approaches to vestibular nerve section
Middle fossa, retrosigmoid, transcochlear, and retrolabyrinthine.
Which of these is associated with the greatest risk of damage to VII
Middle fossa.
What are the contraindications to vestibular nerve section
Only hearing ear, signs of central vestibular dysfunction, poor medical health.
What are the criteria for “probable” Meniere’s disease
Only I episode of vertigo plus the other criteria for “definite” disease.
What is the prognostic significance of a normal AP-SP prior to surgery
Outcomes are significantly better.
Which patients are least likely to benefit from vestibular rehabilitation programs
Patients with fluctuating nonstable vestibular lesions such as with Meniere’s disease; patients in whom no provocative maneuvers or postural control abnormalities are found on examination.
In terms of functional level, which patients with Meniere’s disease are candidates for chemical or surgical labyrinthectomy
Patients with functional levels of 4, 5, or 6.
What is the most common and most difficult to manage problem after any vestibular destructive surgery
Persistent dysequilibrium (20%).
What % of cases occur in the posterior SCC? Horizontal SCC
Posterior 80 - 95%; horizontal 5 - 20%.
Which way is the sigmoid sinus retracted in the retrolabyrinthine approach to vestibular nerve section
Posteriorly.
What does computerized dynamic platform posturography specifically measure
Postural stability and sway.
What medication extends the half-life and facilitates CSF penetration of penicillin
Probenecid.
What is the earliest indicator of hydrops on ECochG
Ratio of SP to AP >30%.
Why is posterior SCC ablation most often the procedure of choice
Relatively easier, less risk to hearing, excellent long term results (approaches 1 OO%).
Which of these approaches is at higher risk for a CSF leak
Retrolabyrinthine.
Which of these is most likely to result in postoperative headaches
Retrosigmoid.
Why is ticlid only warranted in patients unable to tolerate aspirin
Risk of life-threatening neutropenia.
Which part of the vestibular labyrinth detects angular acceleration
Semicircular canals.
Where are cupula found
Semicircular canals.
What therapeutic maneuver is based on the cupulolithiasis theory
Semont.
What are the surgical options for treatment of BPPV
Singular neurectomy, posterior SCC ablation.
What clinical finding is pathognomonic for a lesion at the craniocervical junction
Spontaneous downbeat nystagmus with the eyes open, in the primary position that increases with lateral gaze or head extension.
What are the disadvantages of singular neurectomy
Technically difficult, I 0% risk of SNHL, and nerve may be inaccessible under the basal turn of the cochlea in a small number of patients.
What are the criteria for “certain” Meniere’s disease
The above criteria plus histopathologic confirmation.
What is the most important factor in the ototoxic effect of aminoglycosides
Total cumulative dose.
What are the 2 approaches to labyrinthectomy
Transmastoid and transcanal.
What is the most consistently reliable objective test for hydrops
Transtympanic electrocochleography ( ECochG ).
Balance is determined by what 3 systems
Vestibular, vestibulo-ocular (visual), and vestibulospinal (proprioceptive) systems.
What are the physical exam findings in patients with BPPV
With the Dix-Hallpike maneuver, rotatory nystagmus towards the undermost ear accompanied by vertigo, both with a latent period of 5-30 s and duration
