DISORDERS OF VESTIBULAR

SYSTEM DR. DAVIS THOMAS

DR. DAVIS THOMAS

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Introduction Basic inputs - vision, proprioception, and

vestibular system Provide ocular stability, gait control, and

balance Disorders of vestibular system are major

disruptors causing spatial disorientation Many causes of dizziness, vertigo when

caused by a loss of vestibular function Management strategies for vestibular

disorders has continued to evolve

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Pathophysiology Balance requires –

Normal functioning vestibular systemInput from visual system (vestibulo-ocular)Input from proprioceptive system (vestibulo-spinal)

Central causes compromise central circuits that mediate vestibular influences on posture, gaze control, autonomic fx

Disruption of balance between inputs results in vertigo

Goal of treatment: restore balance between different inputs

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Pathophysiology Vestibular system influences autonomic

system Intimate linkage in brainstem pathways

between vestibular and visceral inputs Alteration of vestibular inputs results in:

nausea, vomitingPallorRespiratory/circulatory changes

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Vestibular Neuritis Sudden onset of peripheral vertigo Usually without hearing loss Period of several hours - severe Lasts a few days, resolves over weeks Inflammation of vestibular nerve -

presumably of viral origin Spontaneous, complete symptomatic

recovery with supportive treatment Treatment aimed at stopping inflammation

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BPPV Most common cause Dysfunction of posterior SCC Cupulolithiasis vs. Canalithiasis Cupulolithiasis

Calcium deposits embedded on cupulaPSCC becomes dependent on gravity

CanalithiasisCalcium debris (otoconia) displaced into PSCCDoes not adhere to cupula

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BPPV Head movements

Looking upLying downRolling onto affected ear

Result in displacement of “sludge” / otoconia Vertigo lasting a few seconds Treatment approaches

Liberatory maneuversParticle repositioningHabituation exercises

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BPPV Epley Canalithiasis Canalith repositioning Move into vestibule Cure rates

80% - one treatment100% - multiple

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BPPV - Epley

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Vertebrobasilar insufficiency Vertigo, diplopia, dysarthria, gait ataxia

and bilateral sensory & motor disturbance

Transient ischemia - low stroke risk Antiplatelet therapy - aspirin 325mg qD Ticlid

Platelet aggregate inhibitorRisk of life-threatening neutropeniaOnly in patients unable to tolerate aspirin

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Migraine Concomitant vertigo and disequilibrium Headache control improves vertigo Diagnostic criteria

Personal/family historyMotion intoleranceVestibular symptoms - do not fit other

causes Theories - vascular origin, abnormal

neural activity (brainstem), abnormal voltage-gated calcium channel genes

Meniere’s Disease

History 1861 – Prosper Meniere describes classic symptoms

and attributes to labyrinth

1871 – Knappin theorizes dilatation of membranous Labyrinth

1938 – Hallpike and Portman confirm endolymphatic hydrops via temporal bone histology

1972 – AAOO defines the disease criteria

1985 – AAO-HNS revises the definition and establishes reporting protocols

1995 – AAO-HNS revises the definition and reporting protocols again

Definition: A disease of the membranous inner ear

characterised by deafness, vertigo and usually tinnitus , which has as its pathologic correlate hydropic distension of the endolymphatic system.

Meniere’s disease Synonym – endolymphatic hydrops Idiopathic Menier’s syndrome – secondary Trauma Viral infections Syphilis Cogan’s syndrome Otosclerosis Autoimmune diseases

AAO-HNS CHE 1995 Meniere’s is diagnosed by

Episodic Vertigo○ Spontaneous, lasting minutes to hours○ Recurrent, must have 2 episodes > 20 min.○ Nystagmus during episodes

Fluctuating Hearing loss○ Avg (250, 500, 1000) 15 dB < Avg (1000, 2000, 3000)

or○ Avg (500, 1000, 2000, 3000) 20 dB > than other ear ○ For bilateral disease Avg (500, 1000, 2000, 3000) > 25

dB in the studied earRoaring Tinnitus

Aural pressure

Lermoyez syndrome Variant of meniere`s Reversed meniere`s Initially hearing loss and tinnitus develop which

persist for prolonged periods. Then vertigo develops with improvement of

hearing and tinnitus TUMARKIN CRISES: sudden unexplained fall

without loss of consciousness or associated vertigo.

deformation of otolithic membrane of utricle or saccule

Cochlear hydrops - only features of cochlear

involvement - vertigo is absent - block at the level of ductus reunionsVestibular hydrops - typical episodic vertigo - cochlear functions are normal

CLASSIFICATION OF ENDOLYMPHATIC HYDROPS

I. 1.PRIMARY 2.SECONDARY(SYPHILIS)

II. 1.EARLY ONSET 2.DELAYED ONSET

III. 1.TYPICAL 2.ATYPICAL

IV. 1.VESTIBULAR 2.COCHLEAR

AAO-HNS CHE 1995 Definite Meniere's disease

Two or more definitive spontaneous episodes of vertigo 20 minutes or longer

Audiometrically documented hearing loss on at least one occasion

Tinnitus or aural fullness in the treated ear Other causes excluded  See staging chart

Certain Meniere's disease Definite Meniere's disease, plus histopathologic confirmation

See staging chart Stage PTA 1 <=25 2 26-40 3 41-70 4 >70

AAO-HNS CHE 1995 Possible Meniere's disease

Episodic vertigo of the Meniere's type without documented hearing loss, or

Sensorineural hearing loss, fluctuating or fixed, with dysequilibrium but without definitive episodes

Other causes excluded

Probable Meniere's disease One definitive episode of vertigo Audiometrically documented hearing loss on at least one occasion Tinnitus or aural fullness in the treated ear Other causes excluded 

Stage PTA1 <=252 26-403 41-704 >70

Aetiology Genetic Anatomical Traumatic Viral infection Allergy Autoimmune Psychosomatic

Pathophysiology Endolymphatic hydrops leads to distortion of membranous

labyrinth

Reisner’s membrane can be seen bulging into the scala vestibuli in some histologic studies

Microruptures may lead to episodic attacks which resolve when the tears heal

Pathophysiology Theories behind endolymphatic hydrops

Obstruction of endolymphatic duct/sacHypoplasia of endolymphatic duct/sacAlteration of absorption of endolymphAlteration in production of endolymphAutoimmune insult Vascular originViral etiology

PathophysiologyProdromal stage of gradual distension of endolymphatic system

Distension progress leading to thinning & atrophy of Reissner’s membrane &saccular wall

Rupture &sudden release of large volume of endolymph in small perilymph space

Sensory & neural structure exposed to K + rich endolymph

Sudden HL & vertigo

When perilymphatic compartment is restored to normal, symptoms subside

Aided by the collapse, the rupture heals & the process is repeated.

DIAGNOSIS

AAO-HNS CHE 1985 Meniere’s is diagnosed by

Vertigo○ Spontaneous, lasting minutes to hours○ Recurrent, must have more than 1 episode○ Associated with nystagmus

Hearing loss○ Fluctuating sensorineural ○ Low-frequency or flat

Tinnitus Vertigo treatment reporting standard

0 = Complete control 1-40 = Substantial control 41-80 = Limited control 81-120 = Insignificant control > 120 = Worse

Hearing treatment reporting standard PTA reported 500, 1000, 2000, 3000 kHz If multiple pre and post levels are available, the worst is always used PTA is considered improved / worse if a 10 dB difference is noted SDS is considered improved / worse if a 15% difference is noted

Avg spells/month post-treatment (24 mon recommended)

x 100 = Control LevelAvg spells/month pre-treatment

(6 mon recommended)

AUDIOLOGICAL INVESTIGATION

TFT – Reveals SN loss PTA – Early disease - low frequency SN

loss – Late disease - high frequency SN loss

0102030405060708090

100110

500 1000 2000 4000 8000

0102030405060708090

100110

500 1000 2000 4000 80000

102030405060708090

100110

500 1000 2000 4000 8000

Early Stage Later Stage

AUDIOLOGICAL INVESTIGATION Speech reception threshold very closely

matching PTT in over 90% Speech discrimination score

Between attacks – 55 – 85 %During attacks – Low

Test for RecruitmentSISI – better than 70 %Stapedial replex +ve

Tone Decay Test – less than 20 dB Bekesy Audiometry – Type II curve

AUDIOLOGICAL INVESTIGATION ElectrocochleographyIt’s a diagnostic and prognostic test

Summating Potential (SP) is larger and more negative

SP/AP Ratio more than 30 % (Normal – 20%)

Normal M.D

GLYCEROL TEST To confirm the diagnosis and useful mainly on

prognosis Procedure 1.5 ml / kg glycerol with equal amounts of water +ve Test – 10 dB or more @ 2 or more frequency or

speech discrimination improves 12% or more -ve Test – Do not reach +ve criteria Decremental – Threshold worse by 10 dB +Ve Glycerol Test – C.I for Labyrinthectomy

ASSESMENT OF VESTIBULAR FUNCTION Caloric Test

30 – 50 % of M.D shows canal paresis on the affected side

Electronystagmography

RADIOLOGICAL INVESTIGATION X-Ray temporal bone

Hypocellularty, sigmoid sinus placed more medially and anteriorly

CT Scan To see the size, position of VA and see the size and location of

Endolympotic sac or dehiscent sup semi circular canal. To see peri aqueduct and perilabyrithine penumatization.

MRI Scan (With and without contrast)Evaluation of skull base tumours / C.P. angle

lesions / vascular lesions / multiple sclerosis / vascular compression of 8th N / acoustic neuroma

(with Gadolinium)

Special Tests Vascular imaging

Non invasive : a) Doppler Ultra Sonography b) Colour Doppler c) M.R. Angiogram (M.R.A)

Invasive : a) Conventional Angiogram b) C.T. Angiogram

Estimation of the followings

Full Blood CountESRT3, T4 & TSHUrea, ElectrolytesCholesterol & TriglyceridesGlucose & GTTVDRL & FTA-ABS

TREATMENT General measures Medical treatment Surgical treatment

General measures Dietary restriction of salt, caffeine,

alcohol, nicotine Cessation of smoking Intermittent dehydration Avoid activities requiring body balance Reassurance Bed rest

Medical Therapy Diuretics - Frusemide Vasodilators– Carbogen, Histamine, Betahistine, Nicotinic acid Labyrinthine sedative– Promethazine,

Dimenhydrinate, Prochlorperazine

SYMPTOMATIC RELIEF DURING ACUTE EPISODES

VESTIBULAR SUPPRESSANTS:i. Phenothiazines-

prochlorperazine,perphenazineii. Antihistamine-cinnarizine,

cyclizine,dimenhydrinate,promethazine,meclizine

iii. Benzodiazepines-reduce activity in vestibular nuclei & relieve anxiety associated with the attack- diazepam,lorazepam

iv. Transdermal scopalamine hydrochloride, an anticholinergic agent

PROPHYLAXIS BETWEEN ACUTE EPISODES

TO REDUCE ENDOLYMPHATIC ACCUMULATION

SALT RESTRICTION DIURETIC THERAPY(hydrochlorthiazide,

chlorthalidone,acetazolamide) HYPEROSMOLAR DEHYDRATION

Intratympanic Ablation Fowler (1948) and Schuknecht (1957)

established role of aminoglycoside therapy.Streptomicin used initiallyVertigo eliminated in all patientsProfound hearing loss in all patients

Gentamicin treatment now preferredTheoretical targets of therapy are

○ Dark cells of the stria vascularis○ Planum semilunatum of the semicircular canals

Higher doses destroy the hair cells of the cochlea

Meniett Device Transtympanic “Micropressure”

TreatmentFDA approved in 1999 as a class II

deviceTreatment self-administered TIDEach treatment is three 1-minute

cyclesApplies intermittent, alternating

pressure 0-20 cm H20Requires a tympanostomy tube

Meniett Device

Criteria: “active symptoms of vestibular or cochleovestibular hydrops”

Improvement in tinnitus, vertigo & ear fullnessImprovement in hearingRequires tympanotomy tubeProblems

○ Tube otorrhea, blockage, extrusion○ Recurrence of disease after therapy cessation

Precautions & Prerequisites for Surgery

Accurate diagnosis Failed medical management Risks Vs Benefits Bilaterality of the disease Health status

Meniere’s Disease. Classification

Conservative Ablative Miscellaneous

Conservative surgery for Meniere’s Residual hearing preserved-50dB SRT,50%SDS 1) Sac surgery :

a) Endolymphatic sac decompression b) Endolymphatic mastoid

shunt(shea,Arenberg.morrison) c) Endolymphatico subarachnoid shunt(austin)

2) Selective vestibular nerve section 3) Sacculotomy

4) Cody Tack procedure 5) Otic periotic shunt 6) Cochleosacculotomy

Meniere’s

Ablative Residual hearing sacrificed

1)Labyrinthectomy2) Labyrinthectomy with cochleo vestibular neurectomy

Meniere’s

Unilateral Disease1. Serviceable hearing

Conservative surgery-Sac surgery2. Poor hearing

Ablative surgery-Labyrinthectomy/Nerve section

Bilateral Disease1. Both ears good hearing Sac surgery-Uni/Bilateral2. Only Hearing Ear Sac surgery3. Both poor Rehabilitation exercise/Nerve section

Meniere’s

Meniere’s Endolymphatic Sac Surgery

AimTo preserve both auditory & vestibular functionPrincipleDecompress or open SacIncrease drainage & ResorptionEliminate hydropsDecrease sequelae & symptoms

Meniere’s Endolymphatic Sac Surgery Indications

Failed medical treatment with serviceable hearing

Only hearing earFluctuating hearing loss 2-3yrs with medical

treatment Contraindications

Poor hearingDecrimental glycerol test

Meniere’sProcedure

•Cortical mastoidectomy done•Identify -Lateral & post semicircular canal -Vertical segment of 7th nerve -Posterior fossa dural plate•Donaldsons line drawn•Sac identified and opened

Advantages of Sac Surgery Better hearing No post op disequilibrium Less risk Preserves both components

Complications Facial nerve injury Hearing loss CSF leak Meningitis

Final surgical option for control of vertigo 1904 described Transcanal, transmastoid PTA 70, discrim 20% Indications

- Unilateral poor hearing - Negative Glycerol test

Labyrinthectomy

Overview Acute Therapy

Long-Term Stabilization Non-invastive medical

treatments Alternative options

Non-Destructive Therapy Medical: IT Steroids Surgical: Mastoid shunt

Destructive Therapy Medical: IT Gentamicin Surgical

○ Nerve section○ Labyrinthectomy

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Conclusions Vestibular complaints common to ENT Thorough evaluation and understanding Dx and treat acute symptoms Wean vestibular suppressants Specific pharmacotherapy instituted Chronic, uncompensated disease

benefits from early VRT

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