Meniere’s Disease

                                Meniere’s Disease

Introduction:

 It is also called Endolymphatic hydrops. It is disorder of inner ear where endolymphatic system is distended with endolymph. It is firstd described by Prosper Meniere in 1861.

It is characterized by symptoms complex consist of:
Spontaneous episodic Vertigo
Deafness (fluctuating sensorineural hearing loss)
Tinnitus
Aural fullness

 

Etiology:

Endolymphatic hydrops (Hallpike, 1938)  is due to decreased  absorption of endolymph or increased production of endolymph  ,especially involves cochlear duct & saccule .

Pathogenesis

   1. Endolymphatic hydrops >>> rupture of membranous labyrinth >>>potassium rich endolymph mixes with perilymph >>> sustained inactivation of hair cells & neurons of vestibulo-cochlear nerve bathed in perilymph>>> deafness + vertigo + tinnitus

   2. Increased Sympathetic activity >>> ischemia of cochlear  & vestibular end organs >>>deafness + vertigo

Etiology of Primary Meniere’s disease

 A. Idiopathic                                           
 B. Increased production of endolymph:
       1. Allergy    
       2. Sodium & water retention
       3. Autoimmune       
       4. Viral infection (HSV, Cytomegalo virus)
       5. Increased  sympathetic activity >>>ischemia of stria
                                vascularis>>> fluid transudation

       6. Endocrine :  Hypo (thyroidism, pituitarism, adrenalism), Diabetes, Hyperlipoproteinemia

C. Decreased absorption of endolymph:     
   1. Small size of endolymphatic sac / duct
   2. Obstruction of endolymphatic sac / duct
   3. Ischaemia of endolymphatic sac
   4. Inner ear trauma

Secondary Meniere Syndrome

Clinically resembles Meniere’s disease. Seen in:             
Syphilis
Otosclerosis,
Cogan syndrome (interstitial keratitis)
Post-stapedectomy
Paget’s disease

Clinical Features

 Age: 30 - 60 years, more in males, unilateral.

 1. Vertigo:                     
               Sudden onset, episodic, rotatory, 30 min - 24 hr, along with nausea, vomiting & diaphoresis.  85 % patient have positional vertigo  .Vertigo caused by loud, low frequency sound >>> Tulio phenomenon

 2. Deafness:   
> Accompanies vertigo, improves after vertigo attack, sensori-neural, fluctuant, progressive >Intolerance to loud sound (due to recruitment)
>Distortion of sound frequency, called diplacusis binauralis dysharmonica

3. Tinnitus:               
      Low-pitch, roaring, non-pulsatile, continuous / intermittent. Increased during vertigo attacks

 4. Aural fullness: 
      Fluctuating, not relieved by swallowing

 5. Emotional upset, anxiety, agoraphobia

AAO-HNS Diagnosis Criteria (1995)

A. Vertigo: Spontaneous, > 2 episodes lasting > 20 min
B. Audiogram documented sensori-neural deafness
C. Tinnitus or Aural fullness in diseased ear
D. Other cases excluded
E. Staging as per pure tone average (500 - 3000 Hz):
    1 = < 25 dB 2 = 26 - 40 dB
3 = 41 - 70 dB 4 = > 70 dB

Meniere’s disease variants

1.Lermoyez’s reverse Meniere syndrome:  Deafness>>vertigo >>improvement in hearing
2.Tumarkin’s sudden drop attack: Pt falls without vertigo / loss of consciousness
3.Meyerhoff’s oculo-vestibular response: Vertigo due to opto-kinetic stimulus
4.Cochlear hydrops: deafness & tinnitus only
5.Vestibular hydrops: vertigo only

 E.N.T. Examination 

1.Otoscopy:  Normal tympanic membrane
2.Nystagmus: irritative > paralytic > recovery
3.False +ve fistula sign (Hennebert sign): in 30% pt
4.Rinne test: positive (A.C. > B.C.)
5.Weber test: lateralizes towards better ear
6.A.B.C. test(Absolute bone conduction): decreased in diseased ear

Irritative nystagmus: 

Occurs immediately with onset of an attack, for 20 seconds, toward diseased ear, due to initial excitation of action potential by increasing potassium in perilymph

Paralytic nystagmus: 

Occurs minutes into an attack, toward healthy ear, due to blockade of action potential by increased K+ in perilymph

Recovery nystagmus: 

Occurs hours later, toward diseased ear, due to vestibular adaptation.

Pure Tone Audiometry

1.Rising curve in early stage

2.Inverted curve

3.Flat curve

4.Down sloping curve

Other Dignostic Tests:

1.Speech Audiometry: Score = 50 - 80 %
2.A.B.L.B.: Recruitment present
3.S.I.S.I.:  positive (> 70 % score)
4.Tone Decay Test: negative (decay < 20 dB)

Electro-cochleography findings in Meniere’s disease:
Summation potential : compound action potential ratio > 30 %
Widened SP-AP waveform (> 2msec)
Distorted cochlear micro-phonics


Glycerol Test (confirmatory:
Do P.T.A. & speech audiogram. Glycerol (1.5 ml / Kg), mixed in lime juice given orally. Repeat audio tests after 2 hrs. Test is positive if:
Pure Tone threshold improves > 10 dB
Speech Discrimination Score increases > 15 %
S.P. / A.P. ratio in E.Co.G. decreases > 15 %

Other Investigations
1..Full blood count + ESR
2.Urea, electrolytes
3.RBS, FBS
4.Fasting lipid profile
5.Thyroid function test
6.VDRL, TPHA
7.Immunological assay, antibody screening

TREATMENT:

Treatment of Acute attack

1. Reassurance >>Bed rest + head support
2. Inj. Prochlorperazine (Stemetil):
   12.5 mg I.V., T.I.D. – Q.I.D.
3. Inj. Promethazine (Phenergan):
   25 mg I.V., T.I.D. – Q.I.D.
4.Inj. Diazepam (Calmpose):
   5 mg I.V. stat

Non-surgical treatment

  1. Discussion: Reassurance. Avoid tea, coffee, colas, chocolate, allergens, stress, smoking, alcohol, flying, diving, heights.
 2.Diet: Low salt (1.5 g/day), less fluids. Exercise.
 3.Vestibular Depressants: Cinnarizine, Diazepam, Prochlorperazine, Dimenhydrinate

4..Cochlear VasoDilators: Betahistine, Xanthinol nicotinate, Carbogen (5 % CO2 + 95 % O2), L.M.W. Dextran, Histamine drip.
5.Diuretics: Thiazide + Triamterene
6.Dexamethasone / Ig G: decreases auto-immunity
7.Dehydration by hyperosmolar fluids
8.Hormone replacement therapy

Meniett Device

   It is  Low pressure pulse generator device .Pressure pulses transmitted to round window via grommet >> displace endolymph >> relieve endolymph hydrops.  Used for 5 min, TID.

Surgical treatment of Meniere’s disease

A. Hearing preservation + Balance preservation:
    1. Endolymphatic sac decompression / shunting                                                                                         
    2. Sacculotomy by puncture of footplate   
    3. Cochlear duct piercing via round window
B. Hearing preservation + Balance ablation:
    1. Chemical labyrinthectomy     2. Vestibular neurectomy
     3. Vestibular end organ destruction by USG / cryoprobe
C. Hearing ablation + Balance ablation:
    1. Section of 8th nerve       2. Total labyrinthectomy

A.Decompression Surgery

1. Endolymphatic sac decompression (Portmann)
2. Endolymphatic sac shunting: into sub- arachnoid space or mastoid cavity.
3. Sacculotomy:
    a. Fick’s needle puncture of footplate
    b.Cody’s tack puncture of footplate
4. Cochlear duct piercing via round window

B.Chemical Labyrinthectomy

1. Trans-tympanic drug injection
2. Intra-tympanic drug instillation via grommet
3. Intra-tympanic drug instillation via Silverstein micro wick
4. Trans-tympanic drug perfusion
Drug used: Gentamicin (vestibulo-toxic)

Trans-tympanic gentamicin
26.7 mg/ml solution used
0.75 ml solution instilled in affected ear (via grommet) 3 times daily for 4 consecutive days
After instillation, pt to lie supine with affected ear up for 30 min & not swallow anything
Vertigo control = 94%. Hearing unchanged or improved = 74%. Hearing worsened = 26%.


Trans-tympanic Dexamethasone
Mechanism of action:
 reducing inflammation
 control of auto-immune injury
Solution strength: 0.25 mg/ml
Dose: 5 drops every alternate day for 3 months

Vestibular Surgery
Denervation of vestibule by vestibular neurectomy via middle cranial fossa
Destruction of vestibule (via round window  or lateral semicircular canal) by:
             1. Cryo-probe
             2. Ultrasound probe

Total Destructive Surgery

Destroys both cochlear & vestibular functions.
Done in pt with severe deafness.
Types of surgery are:
Section of vestibular + cochlear nerves
Trans-mastoid total labyrinthectomy

Hearing level reporting
Pure Tone Average taken for 0.5, 1, 2 & 3 KHz
If multiple pre and post levels are available, worst is always used
PTA is considered improved / worse if a 10 dB difference is noted
Speech Discrimination Score is considered improved / worse if a 15% difference is noted

Prognosis

60% have complete control of vertigo & 40% have good hearing, without any treatment
Medical & surgical therapies show high levels of improvement with placebo
Results vary greatly between different series
Average result:  Level A + B = 60 - 80%
                                Level C = 20 - 30%
                                Level D + E + F = 10 - 20%