MÉNIÈRE’S DISEASE

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WHAT IS MENIERE’S DISEASE? In 1861 Prosper

Meniere described a syndrome characterized by deafness, tinnitus, and episodic vertigo. He linked this condition to a disorder of the inner ear.

In 1871 Knapp advanced the hypothesis that hydrops was similar to ocular glaucoma : aural glaucoma

In 1938 Hallpike and Cairns described the underlying pathology of Meniere’s disease as being endolymphatic hydrops but the precise etiology still remains elusive

HISTORY In 1902, Parry performed a CN VIII

division for vertigo in a patient with suspected Meniere’s disease.

Portman did endolymphatic sac decompression via a transmastoid approach in 1926.

In 1931,McKenzie performed a selective vestibular neurectomy.

DEFINITIONMénière’s disease, also called

endolymphatic hydrops, is a disorder of the inner ear where the endolymphatic system is distended with endolymph. It is characterized by

(i) Vertigo,(ii) Sensorineural hearing loss, (iii) Tinnitus and (iv) Aural fullness.

INCIDENCE The disease seems to be more prevalent

among whites, with a variable female-to-male ratio ( ranging from 1:1, 1.3:1, 2:1 ; female preponderance ).

The peak age at onset is in the fourth and fifth decades of life, although presentation can be at almost any age.

The incidence of bilateral disease probably is in the range of 19% to 24%.

Familial occurrence of Meniere’s disease has been reported in 10% to 20% (An AD mode) Migraine is strongly associated in such cases.

The incidence is elevated in persons with specific major histocompatability complexes (MHCs).

Human leukocyte antigens (HLA) B8/DR3 and Cw7 have been associated with Meniere’s disease.

Review of anatomy

FUNCTIONS OF ENDOLYMPHATIC SAC

Resorption of the water content of endolymph

Ability to participate in some ionic exchanges with endolymph

Removal of metabolic and cellular debris, including otoconia

Immunodefense function ( perisaccular )Inactivation and removal of viruses

Secretion of Glycoproteins to attract extra fluid (Glycoproteins act as a driving force for longitudinal

flow)

PATHOLOGY The main pathology is

distension of endolymphatic system,mainly affecting the cochlear duct (scala media) and the saccule, and to a lesser extent the utricle and semicircularcanals. The dilatation of cochlear duct is such that it may completely fill the scala vestibuli; there is marked bulging of Reissner’s membrane, which may even herniate through the helicotrema into the apical part of scala tympani

Endolymphatic hydrops causes distortion of membranous labyrinth

Pressure building up in the scala media may cause mirco ruptures of membranous labyrinth

This would account for the episodic nature of the attacks

Healing of these ruptures causes resolution of the disorder

Main pathology here is distention of endolymphatic system due to increased volume of endolymph

1. Increased production of endolymph2. Faulty absorption3. Both

AETIOLOGY

Exact cause not known1. Defective absorption by endolymphatic sac2. Vasomotor disturbances: there is

sympathetic over-activity resulting the spasm of internal auditory artery and/or its branches intefering with the function of cochlear or ventibular sensory neuroepithelium.

3. Allergy 4. Sodium and water retention5. Hypothyroidism(3% of cases)6. Autoimmune and viral aetiologies

POSTULATED THEORIES

Anatomical-abnormalities Genetic- AD Immunological - immune complex

deposition Viral-serum IgE to herpes simples virus

types I and II, Epstein-Barr virus and CMV

Vascular-associated with migraines Metabolic-potassium intoxication

Meniere’s disease

Autoimmune process

Viral infection(herpes family)

stress

Sodium and water retention

tinnitus

Episodic vertigo

Aural fullness

Endocrinal(hypothyroidism)

Defective absorption by

sacFood or inhalant allergen

Fluctuating hearing loss

Normal membranous labyrinth Dilated membranous labyrinth in Meniere's disease (Hydrops)

TYPES Classical Meniere’s disease Vestibular Meniere’s disease –

vestibular symptoms and aural pressure Cochlear Meniere’s disease – cochlear

symptoms and aural pressure Lermoyez syndrome – Reverse

Meniere’s Tumarkin’s crisis – Utricular Meniere’s

variant of Meniere’s disease sudden sensorineural hearing loss,

which improves during or immediately after the attack of vertigo.

Cause is sudden spasm of the labyrinthine artery followed by immediate dilatation

TBD showed hydrops and membrane rupture typically in basal cochlea and saccule

LERMOYEZ SYNDROME

TUMARKIN’S CRISIS AKA Tumarkin’s drop attacks abrupt falling attacks of brief

duration without loss of consciousness.

due to an enlarging utricle due to excess endolymphatic volume

an erroneous vertical gravity reference occurs as a consequence of an abrupt change in otolithic input. This in turn generates an inappropriate postural adjustment via the vestibulospinal pathway, which results in a sudden fall.

CLINICAL PRESENTATION The typical history consists of recurring attacks of

vertigo (96.2%) with tinnitus (91.1%) and ipsilateral hearing loss (87.7%).

Attacks often are preceded by an aura consisting of a sense of fullness in the ear, increasing tinnitus, and a decrease in hearing.

The classic presentation is not always detailed by the patient. This is particularly true early in the disease presentation. the disease seems to manifest with a predominance of either vestibular or auditory complaints, 50% of patients came to medical attention with vertigo and hearing loss together, 19% with vertigo only, and 26% with only deafness.

HEARING LOSS AND TINNITUS

• Sensorineural hearing loss is fluctuating and progressive, with the sensation of fullness or pressure in the ear.

• In only 1% to 2% of patients does the hearing loss progress to profound deafness.

• Additional features include diplacusis, a difference in the perception of pitch between the ears (43.6%) and recruitment (56%) .

• Tinnitus tends to be nonpulsatile and variously described as whistling or roaring. It may be continuous or intermittent. Tinnitus often begins, gets louder, or changes pitch as an attack approaches. Frequently a period of improvement follows the attack.

• The Romberg test generally shows significant instability and worsening when the eyes are closed.

• The Weber tuning fork test usually lateralizes away from the affected ear.

• The Rinne test usually indicates that air conduction remains better than bone conduction.

• Complete neurologic evaluation is important. New-onset vertigo might be an early sign of stroke, migraine, or brainstem compression that may require emergent evaluation and care.

AUDIOMETRYParticularly helpful to document present hearing acuity and to detect future change.

-The patient may not notice a loss at specific frequencies. Low-frequency or mixed low- and high-frequency insufficiency may be observed.

- Typically, the lower frequencies are affected more severely. This is due to preferential sensitivity of the apex to the hydrops.

- Multiple hearing tests, which document fluctuating hearing loss, are helpful in diagnosing Ménière.

The diagnosis of Meniere disease is made based on a careful history and physical exam.

If the work-up is normal and the classic symptoms continue, the diagnosis of Meniere disease is made.

DIAGNOSIS

AUDIOGRAM TYPICAL OF EARLY MENIERE'S DISEASE ON THE RIGHT SIDE (X=LEFT, O=RIGHT). THERE IS A LOW-TONE SENSORINEURAL HEARING LOSS.

AUDIOGRAM TYPICAL OF MIDDLE-STAGE MENIERE'S DISEASE, AGAIN ON THE RIGHT SIDE. HEARING IS REDUCED AT ALL FREQUENCIES, BUT MORE SO AT HIGH AND LOW FREQUENCIES.

AUDIOGRAM TYPICAL OF LATE-STAGE MENIERE'S DISEASE, AGAIN ON THE RIGHT SIDE. HEARING IS FLAT, AND UNAIDABLE ON THE RIGHT SIDE.

LOUDNESS RECRUITMENT This is abnormal

growth in the perceived intensity of sound

This is usually positive in patients with Meniere’s disease

ABLB is the test used to look for the presence of recruitment

ELECTROCOCHLEOGRAPHY Ratio of amplitudes of the SP

and the 8th cranial nerve action potential (AP), the SP/AP ratio.

The SP becomes relatively larger in hydrops; accordingly, the SP/AP ratio increases; SP:AP > 0.45

The summating potential (SP) is larger and more negative due to distention of the basilar membrane into the scala tympani, causing an increase in the normal asymmetry of its vibration

DIAGNOSIS No single test makes the diagnosis of

Meniere disease. Rather a complete history that includes a detailed description of the pattern of disease presentation, supported by quantitative testing, is required. The most recent definition of the disease has been established by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology– Head and Neck Surgery (AAO-HNS); this is summarized as follows:

AAO-HNS CRITERIA FOR MENIERE’S DISEASE DIAGNOSIS

Major Symptoms

1.Vertigo Recurrent, well-defined episodes of spinning or rotation • Duration

from 20 minutes to 24 hours. Nystagmus associated with attacks Nausea and vomiting during vertigo spells common No neurologic symptoms with vertigo

2.Deafness Hearing deficits fluctuate Sensorineural hearing loss Hearing loss progressive, usually unilateral

3.Tinnitus Variable, often low-pitched and louder during attacks Usually unilateral Subjective

Possible Meniere’s disease1. Episodic vertigo without hearing loss or2. Sensorineural hearing loss, fluctuating or fixed, with dysequilibrium,

but without definite episodes 3. Other causes excluded

Probable Meniere’s disease1. One definitive episode of vertigo2. Hearing loss documented by audiogram at least once3. Tinnitus or sense of aural fullness in the presumed affected ear 4. Other causes excluded

Definite Meniere’s disease1. Two or more definitive spontaneous episodes of vertigo lasting at

least 20 minutes2. Audiometrically documented hearing loss on at least one occasion3. Tinnitus or sense of aural fullness in the presumed affected ear4. Other causes excluded

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

AAO-HNS CRITERIA FOR MENIERE’S DISEASE SEVERITY Vertigo a. Any treatment should be evaluated after at least 24 months.b. Formula to obtain numeric value for vertigo:

ratio of average number of definitive spells per month after therapy divided by definitive spells per month before therapy (averaged over a 24-month period) × 100 = numeric value.

Numeric value scale Control Class 0 Complete control of

definitive spells A

0-40 Limited control of definitive spells

B

41-80 Insignificant control of definitive spells

C

81-120 D>120 Secondary treatment

initiated E

Disability a. No disabilityb. Mild disability: intermittent or continuous

dizziness/unsteadiness that precludes working in a hazardous environment.

c. Moderate disability: intermittent or continuous dizziness that results in a sedentary occupation

d. Severe disability: symptoms so severe as to exclude gainful employment

HEARING Hearing is measured using a four-frequency pure-tone

average (PTA) of 500 Hz, 1 kHz, 2 kHz, and 3 kHz. • Pretreatment hearing level: worst hearing level during 6

months before therapy • Post-treatment hearing level: poorest hearing level measured

18-24 months after institution of therapy Hearing classification:

i. Unchanged: ≤10-dB PTA improvement or worsening or ≤15% speech discrimination improvement or worsening.

ii. Improved: >10-dB PTA improvement or >15% discrimination improvement

iii. Worse: >10-dB PTA worsening or >15% discrimination worsening

In 1996, the Committee on Hearing and Equilibrium reaffirmed and clarified the guidelines, adding initial staging and reporting guidelines:

Initial Hearing Level

Stage Four tone average(dB)

1 < 25

2 26-40

3 41-70

4 >70

TREATMENT Therapy is aimed at the reduction of

symptoms, and the optimal curative treatment should stop vertigo, abolish tinnitus, and reverse hearing loss..

OTHER SPECIAL INVESTIGATIONS Electrocochleography Dehydrating Agents Vestibular evoked Myopotentials

Vestibular evoked myogenic potential Measures the relaxation of sternomastoid muscle

in response to ipsilateral click stimulus Brief high intensity ipsilateral clicks produce large

short latency inhibitory potentials (VEMP) in the toncially contracted Ipsilateral sternomastoid muscle

Afferent arises from sound responsive cells in the saccule, conducted via the inferior vestibular nerve.

Efferent is via vestibulo spinal tract Normal responses are composed of biphasic

(positive-negative) waves VEMP reveals saccular dysfunction

VEMP

Glycerol Mannitol Frusemide Isosorbide These tests involve the subject ingesting

glycerol or mannitol and observing for a change in symptoms and a measurable improvement in hearing

Tests are positive if there is pure tone improvement of 10dB or more at two / more frequencies between 200-2000Hz

DEHYDRATION TESTS

First introduced by Klockhoff and Lindblom – 1966

Glycerol is administered in doses of 1.5 mg/kg body wt in empty stomach

Serum osmolality should increase at least by 10 mos/kg

Side effects include Headache, Nausea, vomiting, drowsiness

PTA is performed 2-3 hours after administration

False positivity is rare Positivity depends on the phase of the disease

GLYCEROL TEST

TREATMENT• Dietary modifications and diuretics• Vasodilators • Symptomatic treatment

– Antiverginous medications– Antiemetics– Sedatives– Antidepressants– Psychiatric treament

• Local overpressure therapy

DIETARY MODIFICATION AND DIURETICS Salt restriction and diuresis may be the best

initial therapy for Meniere disease. The goal of salt restriction and use of diuretics is to reduce endolymph volume by fluid removal and/or reduced production.

Carbonic anhydrase inhibitors such as acetazolamide were recommended based on the localization of carbonic anhydrase in the dark cells and the stria vascularis

Despite the lack of hard evidence of their efficacy, we feel that a low-salt diet combined with diuresis is an appropriate and effective treatment for Meniere disease that has a low risk of side effects.

• Salt wasting diuretic such as diazide (1 month trial)

• Betahistine (2 week trial, often combined with verapamil)– Relaxes the precapillary sphincters and thus

improves the microcirculation of inner ear– Antivertigo action due to imhibition of massive

impulses to the polysynaptic lateral vestibular nucleus)

• Lipoflavins and vitamins ( hypothetical importance )

LOCAL OVERPRESSURE THERAPY Since 2000, the Meniett

device has been approved for use by the U.S. Food and Drug Administration (FDA). The device is a handheld air-pressure generator that the patient can use to self-administer therapeutic pressure pulses. The pressure is delivered in complex pulses of up to 20 cm of water delivered over 5 minutes, and the device requires a ventilation tube to be placed in the tympanic membrane prior to starting therapy

Restoring balance in the hydrodynamic system of the inner ear by applying low-pressure pulses to the middle ear

A randomized controlled trial demonstrated that patients using the Meniett device experienced a significant decrease in vertigo symptoms for the first 3 months of therapy but that findings afterward were similar to those with placebo.

1. Classic unilateral Meniere’s disease2. Intense vestibular / cochlear symptoms3. Failed medical therapy4. Over 65 years of age5. Imbalance / aural fullness / tinnitus

after gentamycin treatment

INDICATIONS

SURGICAL TREATMENT Intratympanic injection Endolymphatic sac surgery Nerve section Labyrinthectomy

DEXAMETHASONE To be offered when vertigo is intractable but the patient still

has some functional hearing.

The risk of hearing loss or other complications from the steroid injection appears to be low.

A small randomized trial has shown complete resolution of vertigo symptoms in 82% of patients receiving dexamethasone, compared with 57% receiving saline injection.

Dexamethasone injections may need to be repeated every 3 months to maintain the patient free of vertigo symptoms, although the optimal dosing frequency is variable and unknown.

Concentrations used have varied from 2 to 24 mg/mL.

After giving puncture in the TM, with needle being just above the round window 0.5ml of hyaluronidase & 1 ml of 16mg dexamethasone mixed together; injected in ME

Pt instructed to lie down for 3 hrs with injected ear up, entire process repeated 3 consecutive days

GENTAMICIN Has a vestibulotoxicity that is high relative to its

cochleotoxicity; accordingly, it can be used to control vestibular symptoms while sparing hearing.

The gentamicin can be administered through either a tympanostomy tube or directly injected through the tympanic membrane.

Peripheral vestibular deficits are evident on head thrust testing after even a single dose of gentamicin

• 40 mg/ml gentamycin is buffered with soda bicarb (pH6.4) final concentration 26.7mg/ml.

• 0.7ml of gentamicin injection mixed with 0.3ml of sodium bicarbonate solution

• Three injections are given per day in outpatient setting• Injections are given for 4 days• After injection patient should lie supine with the infiltrated ear up

for 30 mins

SURGICAL TREATMENT The ideal procedure for Meniere disease

would restore normal function, or at least preserve residual function, while stabilizing the ear. As discussed next, two operative procedures have been proposed to achieve this goal:

Cochleosacculotomy and Endolymphatic sac surgery(ELS) surgery. Vestibular neurectomy

Cochleosacculotomy aims to create a fracture dislocation of the osseous spiral lamina (and hence a permanent fistulization of the endolymph-containing cochlear duct) by inserting a hook through the round window metnbrane.

Sacculotomy was proposed by Fick in 1964, and consisted of using a needle to puncture the saccule through the stapes footplate. A later variation on this technique involved leaving a sharp prosthesis in the footplate that ruptured the saccule each time it expanded.Long-term follow-up of patients so treated has shown an unacceptable degree of hearing loss

COCHLEOSACCULOTOMY.

•Cochleosacculotomy creates a fracture dislocation of osseous spiral lamina, this procedures have highdegree of hearing loss• Helpful in treating debilitated

patients• Involves disruption of osseous

spiral lamina• Angular pick introduced via

round window towards oval window. It will accommodate 3 mm long pick

• After perforation the pick is withdrawn and the round window is sealed by fat

Endolynmphatic sac surgery begins with simple mastoidectomy and identification of the tegmen, sigmoid sinus, and facial ridge.

ENDOLYMPHATIC SAC SURGERY

Once these landmarks are established, the horizontal and posterior canals should be skeletonized and the bone over the posterior fossa thinned

The last shell of bone covering the sigmoid sinus (SS) and the posterior fossa dura (PFD) is being removed

The superior edge of the endolymphatic sacis identified; it usually lies at or belowDonaldson's line, which extends posteriorlyalong the plane of the horizontal canal andbisects the posterior canal.

After the sigmoid sinus (SS) and the posterior fossa dura(PFD) have been uncovered, retraction of the dura posteriorly reveals the endolymphatic duct (<) exiting medial to the posterior semicircular

canal (PSC)

The procedure from this point varies according to which endolymphatic surgery is planned.Decompression of the sac requires only that the bone of the posterior fossa plate be removed

Using microscissors, the lateral wall of the endolymphatic sac(<) is separated from its medial wall (^). PSC Posterior semicircular canal

Endolymphatic shunting is most simply performed by incising the exposed sac and placing a stent to keep the incision open.

The popular Paparella and Hanson technique involves opening the edge of the sac, lysing any intraluminal adhesions, and probing the duct to insure that it is patent. A piece of Silastic" is placed through the incision in the sac allowing long-term drainage

A T-shaped piece of silicone is coiled and placed into a lateral incision in the endolymphatic sac to create a drainage path to the mastoid cavity.

Endolymphatic-subarachnoid shunt. After exposing and opening the lateral wall of the endolymphatic sac, the medial wall of the sac is incised to open the lateral prolongation of the basal cistern. Dissection in the cistern is carried out bluntly to avoid venous injury. A silicone (Silastic®) shunt is inserted to maintain drainage path between the endolymphatic sac and the basal cistern.The lateral endolymphatic sac is carefully closed with a fascia graft to prevent cerebrospinal fluid leak.

Several approaches to the vestibular nerve have been described.

The earliest approach was the retrosigmoid

The term retrosigmoid and suboccipital are now used interchangeably.

The middle fossa approach to the internal auditory canal and superior vestibular nerve was developed by William House in the early 1960s and was later modified to include inferior vestibular nerve section.

VESTIBULAR NEURECTOMY

RETROSIGMOID APPROACH

The skin incision is made as shown.

An extended mastoidectomy has been achieved in a left temporal bone

oThe dura has been uncovered from the overlying bone.

A 5 × 5-cm craniotomy flap (CT) has been created. Note that the craniotomy should be located posterior to the sigmoid sinus (SS) and inferior to the transverse sinus

A septal raspatory is used to detach the craniotomy flap (CT) from the underlying posterior fossa dura

The craniotomy flap is separated from the dura.

An anteriorly based flap (F) is created in the posterior fossa dura (PFD) and fixed anteriorly using sutures. TS Transverse sinus

Through the craniotomy, the acousticofacial bundle (AFB)can be seen entering the internal auditory canal (^). IX

Glossopharyngeal nerve

The vestibular, cochlear, and facialnerves are identified, and then the superior and inferior vestibularnerves can be sectioned . Afterward the dura is reapproximated, and the bone flap is replaced and covered as the wound is closed.

Retrosigmoid approach to vestibular nerve section. The cerebellum is retracted medially giving a view of the superior and inferior vestibular nerves. A, The posterior fossa is exposed and nerves are identified.B, The superior vestibular nerve is separated from the more anterior facial nerve. C, The superior vestibular nerve has been sectioned

The skin incision is made as shown.The site of the craniotomy (CT) carried out for the middle cranial fossa approach.

MIDDLE FOSSA APPROACH

After the craniotomy flap (CT) has been created in a left temporal bone, a septal raspatory is carefully used to separate the bony flap from the middle fossa dura.

The craniotomy is successfully elevated from the middle fossa dura (MFD). EAC External auditory canal, ZP Base of the zygomatic process

The sharp bony edges are smoothed using a diamond burr while the middle fossa dura (MFD) is being retracted using the suction tube. MFP Middle fossa plate, ZP Base of the zygomatic process

Elevation of the middle fossa dura (MFD) from the middle fossa plate (MFP).

The first landmark to be identified is the arcuate eminence(AE)

As dural elevation advances anteriorly, the middle meningeal artery (MMA) is identified next.

The greater petrosal nerve (GPN) is identified next

The middle fossa retractor is fixed at the petrous ridge (PR).

The expected location of the internal auditory canal (IAC).

The bar-shaded areas are the locations for drilling.

A closer view shows that the location of the internal auditory

canal (IAC) has been identified

Further drilling identifies the posterior fossa dura (PFD) under

the thin bone covering.

The bony covering of the posterior fossa dura (*) is being removed.

The bony covering of the internal auditory canal and the posterior fossa dura anterior to the canal (*) is being removed

A hook is used to create a hole in the posterior fossa dura. This step is useful in live surgery, to reduce intracranial pressure

The dura of the internal auditory canal (IAC) is being opened.

The acousticofacial bundle (AFP) can be seen within the

opened internal auditory canal.

The dura of the internal auditory canal has been further removed.

Bill’s bar (BB) can be seen at the level of the fundus.

A small hook is used carefully to dislodge the superior vestibular nerve

The superior vestibular nerve (SV) has been dissected away,

and the hook now is being used to dissect the inferior vestibular nerve

Vestibular nerve section has a complete vertigo control rate of about 85 to 95% with 80 to 90%of patients maintaining their preoperative hearing immediately postoperatively. The procedure offers much greater vertigo control rates than endolymphatic shunt procedures, but is also a more invasive and technically challenging procedure.

LABYRINTHECTOMY Labyrinthectomy is the most destructive

procedure in the treatment of Meniere's as it destroys both hearing and vestibular function

Ideal candidate is a patient with no functional hearing and in whom all more consevative treatment like gentamycin injection have failed

There are two approaches: Transcanal and Transmastoid approach affords much better

exposure and is more popular.

LABYRINTHECTOMY

Transcanal labyrinthectomy. A, Removal of promontory bone and stapes provides wide exposure of the vestibule. B, The utricular neuroepithelium (UN) is removed from the elliptical recess of the vestibule.

The limitation of the transcanal approach is the poor access it yields to the posterior canal, located medial to the facial nerve; thus, complete ablation may not be achieved. The limited exposure also makes the procedure more technically difficult than the transmastoid approach.

The transmastoid approach to labyrinthectomy is more commonly performed and has the advantage of allowing direct visualization of the vestibular end organs as they are removed

The approach begins with a standard postauricular incision.The mastoid cavity is opened with identification of the three semicircular canals and the facial nerve. C, The three semicircular canals are blue lined and traced to their ampullated ends. D, The ampullae and neuroepithelium of the three semicircular canals are exposed, along with the otolithic organs (the saccule and the utricle)

REFERENCES CUMMINGS OTOLARYNGOLOGY HEAD

&NECK SURGERY 6TH EDITION Glasscock-Shambaugh surgery of ear 6th

edition The Temporal Bone A Manual for

Dissection and Surgical Approaches Mario Sanna, M.D.

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