Meniere’s Disease

1. Meniere’s Disease Dr T Balasubramanian MS DLO www.drtbalu.com

2. Definition Meniere’s disease is defined as a symptom complex associated with: Roaring tinnitus Sensorineural hearing loss (Low frequency) Vertigo (episodic) Fullness of the ear These symptoms are associated with dilated membranous labyrinth filled with endolymph www.drtbalu.com

3. History 1747 – Antonio Scarpa described anatomy of membranous labyrinth 1861 – Prosper Meniere described the classic features of Meniere’s disease & attributed it to labyrinthine causes 1871 – Knappin theorized that dilated membranous labyrinth to be the cause of this disorder 1927 – Guild described endolymphatic ciruclation 1938 – Hallpike and Portmann described pathology of Meniere’s disease by studying temporal bones. www.drtbalu.com

4. Where do we stand? 150 years have passed since this syndrome was described Amount of literature accumulated has virtually doubled Only consensus reached so far is that its cause is multifactorial Not all individuals with histological features of Meniere’s disease manifested the classic clinical features (? Unknown factors protecting the individuals) Surgical destruction of sac ameliorates symptoms. (? What role does sac play exactly in endolymphatic circulation) www.drtbalu.com

5. Physiology of inner ear fluids Inner ear contains two types of fluids (perilyimph and endolymph separated by membranous labyrinth. Perilymph is similar in composition to CSF (Containing high Na and low K ions) Endolymph similar in composition to intracellular fluid (Containing low Na and high K concentration). It is secreted by stria vascularis www.drtbalu.com

6. Anatomy of Sac Duct begins at ductusreuniens Duct is a single lumen tube about 2 mm long The duct narrows at the isthmus which lies at the level of vestibular aqueduct www.drtbalu.com

7. Functions of sac Secretory function Absorptive function Immune / defense function www.drtbalu.com

8. Secretions from the sac Aquaporins Glycoproteins like Saccain Endolymph Glycoproteins act as a driving force for longitudinal flow www.drtbalu.com

9. Endolymphatic fluid circulation Longitudinal flow Radial flow Dynamic flow www.drtbalu.com

10. Longitudinal flow Was first proposed by Guild Striavascularis is the principal source This is a slow process Elimination occurs at the endolymphatic sac level www.drtbalu.com

11. Dynamic flow First proposed by Lawrence This is a combination of both longitudinal and radial flow patterns www.drtbalu.com

12. Radial flow This is active process (energy consuming) Production occurs from dark vestibular cells & planumsemilunatum Absorption occurs at the striavestibularis www.drtbalu.com

13. Endolymphatic sinus This is a small membranous bulb located where the endolymphatic duct enters the vestibule This is where the volume of circulating endolymph is monitored Monitoring the volume of endolymph is not possible by sac because it will be interfered by CSF pressure and pressure exerted by lateral sinus www.drtbalu.com

14. How endolymphatic sinus monitors endolymph volume www.drtbalu.com

15. Salt’s findings on endolymphatic flow Composition of endolymph is maintained by striavascularis by controlling the influx of water Normally endolymph is a biological puddle with very little radial / longitudinal flow Only under exceptional circumstances like increased endolymphatic fluid volumes does radial / longitudinal movement towards sac occurs Under normal circumstances radial flow alone is sufficient to maintain endolymph fluid balance and the longitudinal flow due to saccmechanics is not necessary The longitudinal flow is restricted by the isthmus portion of the duct which acts like the constriction seen in the hour glass www.drtbalu.com

16. Mechanism of Meniere’s disease www.drtbalu.com

17. Lake pond hypothesis www.drtbalu.com

18. Drainage theory www.drtbalu.com

19. Drainage theory (contd) Small amounts of excess endolymph can be cleared by radial flow Larger volumes need longitudinal flow for their clearance Endolymphatic sinus temporarily accommodates excess endolymph till the sac is ready for it Endolymphatic valve of Bast isolates pars superior and prevents endolymph from draining out of the utricle www.drtbalu.com

20. Causes Genetic causes Infection Otosclerosis Trauma (physical / acoustic) Syphilis Miscellaneous – Allergy, tumors, leukemia and autoimmune disorders www.drtbalu.com

21. Types of Meniere's disease 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 www.drtbalu.com

22. Lermoyez syndrome This is a variant of Meniere’s disease. It is characterized by sudden sensori neural hearing loss which improves during or immediately after the attack of vertigo. www.drtbalu.com

23. Tumarkin’s drop attacks This variant is characterized by abrupt falling attacks of brief duration without loss of consciousness. This is caused due to an enlarging utricle due to excess endolymphatic volume. Utricular crisis is used to indicate this condition. In the later disease stages the valve of Bast remaining patent may cause sudden drainage of endolymph from the utricle due to longitudinal flow resulting in these drop attacks www.drtbalu.com

24. Incidence Roughly 1 in 1000 individuals are affected Constitutes 10% of all patients attending vertigo clinic Female preponderance Rare in children under the age of 10 Commonly begins between 4th and 5th decades of life Bilateral Meniere’s syndrome is seen in 5% of these patients www.drtbalu.com

25. Pathophysiology 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 www.drtbalu.com

26. Clinical manifestations Episodic vertigo rotatory in nature Ipsilateral hearing loss Aural fullness Roaring tinnitus Diplacusis www.drtbalu.com

27. Stages Stage I – Patient has solely cochlear symptoms Stages II – IV – Patients have progressively more cochlear and vestibular symptoms Stage V – End stage Meniere’s disease (dead ear) www.drtbalu.com

28. Direction of nystagmus Irritative nystagmus during the first 20 mins of attack Paralytic nystagmus follows Later recovery nystagmus starts www.drtbalu.com

29. Diagnostic criteria Possible Meniere’s disease: Episodic vertigo of Meniere’s type without documented hearing loss Fluctuating hearing loss with disequilibrium but without definite episodes Probable Meniere’s disease: One definitive episode of vertigo Audiometrically documented hearing loss at least during one attack Definitive Meniere’s disease Two or more definitive episodes of spontaneous vertigo one atleast lasting for 20 mins. Audiometrically documented hearing loss at least on one occasion Tinnitus and aural fullness in the treated ear www.drtbalu.com

30. Groningen criteria of diagnosis Sensori neural hearing loss combined with: Tinnitus now / in the past Vertigo attacks (at least two present now or in the past) Exclusion of other pathology following Groningen protocol Hearing loss: Sensorineural in nature No demonstrable conductive element Hearing loss of 20 dB or more at one of the usually measured audiometric thresholds Vertigo: Paroxysmal rotatory dizziness, accompanied by nausea / vomiting At least two episodes should be reported during a course of illness. One of the attack should last at least for 5 mins In between attacks there may be periods of unsteadiness www.drtbalu.com

31. Hearing loss Sensori neural in nature Fluctuating and progressive Affects low frequencies Mild low frequency conductive hearing loss (rare) Profound sensori neural hearing loss (End stage) www.drtbalu.com

32. Tinnitus Roaring in nature Could be continuous / intermittent Non pulsatile in nature Frequency of tinnitus corresponds to the region of cochlea which has suffered the maximum damage www.drtbalu.com

33. 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 This test is really time consuming www.drtbalu.com

34. Electro cochleography Increased summating potential / action potential ratio. 1:3 is normal Widened summating potential / action potential complex. A widening of greater than 2 ms is significant Small distorted cochlear microphonics www.drtbalu.com

35. Vestibular tests Not mandatory for diagnosis of Meniere’s disease Caloric test is still performed It is low frequency stimulation (0.003 Hz) of lateral canal Caloric asymmetry will point to the diseased ear 20% difference between the two ears (Jongkee’s formula) is significant www.drtbalu.com

36. VEMP 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 This test is due to the presence of vestibulo collic reflex 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 www.drtbalu.com

37. Dehydration tests Glycerol Frusemide Isosorbide Tests are positive if there is pure tone improvement of 10dB or more at two / more frequencies between 200-2000Hz www.drtbalu.com

38. Glycerol test 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 www.drtbalu.com

39. Medical Management Dietary management Physiotherapy Psychological support Pharmacological intervention www.drtbalu.com

40. Treatment of acute exacerbation Intravenous fluids – dehydration Vestibular suppressants – May delay recovery / rehabilitation process Corticosteroids – May help if tinnitus and deafness are debilitating www.drtbalu.com

41. Low salt diet Frustenberg diet 2 grams / 24 hours (restricted salt intake) Life style modification www.drtbalu.com

42. Role of diuretics Diuretics play a vital role in alleviating acute symptoms This has been in use since 1930’s Thiazide group of drugs are commonly used Frusemide may be used to alleviate acute symptoms Clear scientific evidence is lacking regarding the usefulness of diuretics (cochrane review) www.drtbalu.com

43. Betahistine Cochlear vascular insufficiency has been proposed as one of the mechanism of Meniere's disease Betahistine is supposed to cause vasodilatation of cochlear blood vessels Betahistine has weak H1 agonistic property and considerable H3 antagonist properties It reduces the frequency & intensity of vertigo. Has minimal effect on tinnitus Doesn’t help much with hearing loss (Cochrane review) www.drtbalu.com

44. Intratympanic steroids Immune modulating effects Improves fluid dynamics of inner ear due to mineralocorticoid effects Vertigo was controlled on an immediate basis Methylprednisolone has the best effect as it penetrates the round window better Silverstein microwick can be used for intratympanic drug administration www.drtbalu.com

45. Miscellaneous drugs Isordil ϒ – globulin Urea Glycerol Lithium Anticholinergics – Glycopyrrolate 1-2 mg /day Antidopaminergics – Droperidol 2.5 – 10 mg orally / day Leuprolide acetate – Blocks normal sex hormone production Innovar – A combination of droperidol and fentanyl can be used to suppress vestibular symptoms (can replace endolymphatic sac surgery) Hyperbaric oxygen therapy www.drtbalu.com

46. Other treatment modalities (ancillary) Stress reduction Patient education Hearing aids – can be used to suppress troublesome tinnitus Tinnitus retraining www.drtbalu.com

47. Vibrator therapy Meniett Device Low pressure pulse generator Vibrations are transmitted via external auditory canal Vibrations alter inner ear fluid dynamics by their effects on the oval and round windows Exact mechanism of action is not known It is totally non invasive This device is portable www.drtbalu.com

48. Vibrator therapy steps Diagnosis should be confirmed Ventilation tube should be inserted Patient should be trained for self administration of the treatment Usually administered thrice a day about 5 mins each time Treatment lasts for 5 weeks www.drtbalu.com

49. Indications for vibrator therapy Classic unilateral Meniere’s disease Intense vestibular / cochlear symptoms Failed medical therapy Over 65 years of age Imbalance / aural fullness / tinnitus after gentamycin treatment www.drtbalu.com

50. Contraindications for vibrator therapy Perilymph fistula Acoustic neuroma / brain tumor Retrocochlear damage Low pressure hydrocephalus www.drtbalu.com