MÉNIÈRE’S DISEASE.pptx ent ug presentation

MÉNIÈRE’S DISEASE (IDIOPATHIC ENDOLYMPHATIC HYDROPS)

1. MÉNIÈRE’S DISEASE (IDIOPATHIC ENDOLYMPHATIC HYDROPS)

2. Incidence Etiology Pathogenesis Clinical features Differential diagnosis Investigations Staging Medical Treatment Surgical Treatment

3. Symptom complex consists of : spontaneous episodic vertigo, fluctuating sensorineural hearing loss (SNHL), tinnitus and often a sensation of fluctuating ear fullness

4. INCIDENCE Varies from 7.5 to 157 per 100,000 persons. Affects primarily Caucasians with a slight female preponderance. About 10% of dizzy patients have Ménière’s disease. Age of onset is 4–90 years but peak incidence is in 40–60 years age group. Bilateral disease develops in 47% of cases followed up for 20 years.

5. ETIOLOGY Viral: The causative roles of viruses (HSV, cytomegalovirus or VZV) remain uncertain. Hereditary: Familial occurrence in 10–20% cases. There is an autosomal dominant mode of inheritance. Autoimmune: Certain genetically acquired major histocompatibility complexes specifically human leukocyte antigens (HLA) B8/DR3 and Cw7 have been associated. Stress and vasomotor disturbance : Sympathetic overactivity can cause sudden hearing loss and vertigo due to the spasm of the vessels which supply neuroepithelium of the labyrinth.

6. Allergy: About 50% patients with Ménière’s disease have been reported allergic to inhalants and/or food items. Inner ear can be the “shock organ” in these patients. Hypothyroidism: Approximately, 3% patients with Ménière’s disease have been reported to have hypothyroidism and they respond to thyroid replacement therapy Impaired absorption of endolymph: Ischemia of the endolymphatic sac has been reported in the patients undergoing endolymphatic sac surgery for Ménière’s disease. Poor vascularity of sac can affect its functioning. Sodium and water retention

7. PATHOGENESIS Indequate absorption of endolymph by the endolymphatic sac due to perisaccular ischemia and fibrosis. Overaccumulation of endolymph at the expense of perilymphatic space results in the distortion of membranous labyrinth. Marked bulging of Reissner's membrane may fill the scala vestibuli and/or herniate into apical part of scala tympani through the helicotrema. Alterations in the size of endolymphatic duct and sac along with reductions in tubular specializations of the lining of these structures have been observed.

8. Site: Endolymphatic hydrops mainly occurs in pars inferior (cochlea and saccule) and changes in pars superior (utricle and SCC) are usually less obvious. Basilar membrane gets distended into scala tympani. Hennebert's sign : Saccular distension can not only distort utricle and SCCs but can also come in contact with stapes footplate and cause positive fistula test in the absence of fistula ( Hennebert’s sign). Hair cells and their neurons are usually spared.

9. Acute attack: Membranous rupture, which can occur in any part of the inner ear, allows leakage of potassium-rich endolymph into perilymph. The high concentration of K+ depolarizes the neurons and inactivates both vestibular and auditory neurones that result in vertigo (paralytic nystagmus) and deafness Remission: Healing of membranes allows restitution of normal chemical and clinical status. Progressive hearing loss: Repeated membranous rupture and potassium exposure lead to progressive deterioration in the functions of inner ear.

10. CLINICAL FEATURES 1) Triad: The typical presentation consists of recurring attacks (3–11 per year) of spinning vertigo in horizontal axis (usually for minutes to 2–3 hours) with tinnitus and hearing loss. Attack lasting more than a day is inconsistent with the diagnosis. 2) Vertigo attacks are usually preceded by an aura consisting of fullness in the ear, increasing tinnitus and decrease in hearing. Attacks may be sudden without any warning or may awaken patient from sleep. Cluster of attacks are separated by long remissions. Patients can have single, sporadic attacks or periods of unrelenting recurring attacks. Patient may be minimally inconvenienced or completely incapacitated. Emotional impact may be equivalent to major medical problem.

11. Attacks are often accompanied by nausea, vomiting, diarrhea or sweating. Vertigo is exacerbated with any head movement. Between the attacks, the patient may be totally symptom-free or feel disequilibrium, lightheadedness or tilt. 3) Hearing loss is fluctuating and progressive. Recruitment (intolerance to loud sounds) may be present. The speech discrimination ability is seen impaired during and immediately after the episodes of vertigo. 4) Tinnitus is nonpulsatile and may be whistling or roaring, continuous or intermittent. It becomes louder or changes pitch as an attack approaches and improves after the attack. 5) Ear fullness: It is fluctuating and may occur with the acute attack or before that.

12. 6) Emotional features : They appear due to the apprehension of attacks. Emotional stress can be the cause as well as effect of Ménière’s disease. 7) Lermoyez attack: In this condition, increased tinnitus and HL precede the vertiginous episode and dramatically resolve with the onset of vertigo. 8) Drop attacks (otolithic crises of Tumarkin ) : Occasionally sudden unexplained falls without loss of consciousness or associated vertigo occur. Patient feels pushing or moving during this short-lived spells. Acute utriculosaccular dysfunction leads to inappropriate postural adjustment via vestibulospinal pathway. Other causes of drop spells include cardiogenic, vertebral basilar insufficiency and migraine.

13. DIFFERENTIAL DIAGNOSES Ménière’s disease, which is an idiopathic lesion, is a clinical diagnosis. Migraine and basilar migraine Autoimmune disease of inner ear and otosclerosis Syphilis and Cogan’s syndrome Cardiogenic Vertebral basilar insufficiency Trauma: Head injury or ear surgery Acoustic neuroma

14. INVESTIGATIONS Pure Tone Audiogram Low-frequency fluctuating and progressive SNHL and a coincident nonchanging high-frequency loss. Average pure tone loss is of 50 dB. Profound HL is rare Peaked at 2 kHz (tent-like audiogram). Types: Initially pure tone audiogram (PTA) is falling type due to low-frequency SNHL. With the progress of the disease, it becomes flat (with the involvement of all the frequencies) and in advanced cases it is falling type due to progressive higher frequency SNHL.

15. Special Tests Recruitment: It is present in 56% cases. 2) Short increment sensitivity index (SISI): In comparison to normal 15%, patient’s SISI score is usually more than 70%. 3) Tone decay test: It is absent and patients show decay of less than 20 dB. 4) Speech audiometry: A mean speech discrimination score is about 53%. 5) Glycerol test: Ingestion of glycerin 1.5 g/kg mixed with equal volume of juice is followed by serial audiograms over 3 hours. Positive test: 25 dB shift at three consecutive frequencies, or 16% improvement in speech discrimination

16. 6) Dehydrating agents: Urea, glycerol and furosemide produce measurable improvement in audiometric score, reduction in summating potential (SP) negativity (electrocochleography) and change in gain of vestibulo -ocular response to rotational stimulation. Sensitivity and specificity vary widely. 7) Electronystagmography: Caloric response is significantly reduced in 48–73.5% cases. Complete loss occurs in 6–11%. 8) Electrocochleography Infrequently used. Summating potential: It is larger and more negative due to the distension of basilar membrane into scala tympani. Action potential (AP) of CN VIII: Reduction in amplitude. SP/AP ratio: Increases (most commonly used value).

17. 9) Caloric test: Canal paresis on affected side and/or directional preponderance on healthy side is seen in about 75% of the patients. 10) Imaging: It is usually not required for the diagnosis. Computed tomography scan: Hypoplasia of the endolymphatic sac and duct results in decreased visualization of vestibular aqueduct and reduction in periaqueductal pneumatization. Reduced retrolabyrinthine bone might be predisposing factor to disease. Magnetic resonance imaging (MRI): Significantly smaller and shorter endolymph drainage system. Gadolinium-enhanced MRI: Enhancement of endolymphatic sac reflects inflammation of sac

18. Staging of Ménière’s disease: On the basis of pure tone average (500 Hz, 1,000 Hz, 2,000 Hz and 3,000 Hz) in dB of the worst HL (audiogram) in the interval of 6 months before treatment Ménière’s disease has been graded into following four stages: Stage I: = Up to 25 dB Stage II: 26–40 dB Stage III: 41–70 dB Stage IV: More than 70 dB

19. MEDICAL TREATMENT Following conservative measures are usually taken: General Measures Reassurance: Explaining the benign nature of disease relieves the patient’s anxiety. Lifestyle changes ,Cessation of smoking, Avoid excessive intake of water and salt, Avoid excessive tea, coffee and alcohol, Avoid stress, Avoid flying, diving and working at great heights to prevent accident in cases of sudden episode.

20. B) Acute Attack Reassurance and bedrest Vestibular sedatives: They are given parenterally if vomiting precludes oral use. They take care of vertigo and anxiety and include prochlorperazine ( stemetil ), promethazine theoclate ( avomine ), dimenhydrinate (Dramamine), and diazepam. Atropine can also be very effective. Vasodilators: Inhalation of carbogen (5% CO2 with 95% O2) causes cerebral vasodilation and improves labyrinthine circulation. Histamine diphosphate 2.75 mg in 500 mL glucose slow IV drip helps in managing acute episodes.

21. C) Chronic Phase Dietary modifications -Salt restriction ,Intermittent dehydration, Hyperosmolar dehydration Diuretics -Hyperosmotic diuretic isosorbide ,Acetazolamide: Carbonic anhydrase inhibitor, Furosemide 40 mg on alternate day with potassium supplement may help in some cases Vasodilators: Quantitative improvement was not seen consistently with these medications. -Histamine, betahistine , papaverine analog , eupavarine , nicotinic acid, adenosine triphosphate and dipyridamole. Symptomatic medications: They are beneficial in reducing the symptoms and in improving tolerance. - Antivertiginous , antiemetics, sedatives, antidepressants and psychiatric treatment.

22. Propantheline bromide: -Pro-Banthine 15 mg three times a day is found effective in some cases. Elimination of allergen: -In cases of allergy, the causative allergen should be eliminated or desensitized. Hormones: -Endocrinal hypofunctioning , such as hypothyroidism, need appropriate replacement therapy. Pulsed positive pressure in external auditory canal (EAC) and pressure equalization tube ( Meniett device therapy): -This has been approved by the FDA. Through the ventilation tube (grommet) pressure waves are delivered to round window. As the device is coupled to external ear canal, it can be used by patient at home.

23. Bilateral Ménière’s disease :Parenteral streptomycin: -Streptomycin is primarily vestibulotoxic and usually leaves hearing unchanged. Indicated only for incapacitating bilateral Ménière’s disease. -1.5–3.5 g/day until ice water response is absent (for 17.5 days average; 39 g mean total dose). -20 g total dose preserves some vestibular function, which decreases the disabling oscillopsia and vestibular ataxia. I Immunosuppressant therapy - Chronic steroids and Nonsteroidal immunosuppressant( Methotrexate)

24. SURGICAL TREATMENT Hearing-conservative nonvestibular ablative surgery Endolymphatic sac decompression: The procedure may be combined with insertion of Silastic sheeting, tubing, one-way valve, tubed sponge, gelatin or tissue stent. The drainage pathway is routed to the epidural space by incision of the back wall of the sac. Cochleosacculotomy : When mechanical blockage of utricular and saccular ducts does not allow endolymph to reach endolymphatic sac, perforation of the saccule is done behind the oval window with a pick through the round window.

25. C) Fick and Cody tack procedures: Fick operation creates fistulas in the saccule via the oval window. Cody's tack procedure places a stainless steel tack through the stapes footplate. These techniques are rarely practiced today. D) Transtympanic corticosteroid infusion of middle ear.

26. Hearing-conservative vestibular ablative surgery Vestibular neurectomy: Vestibular division of the auditory nerve is selectively divided to get relief from vertigo. About 95% patients have complete resolution of vertigo. The following approaches may be employed:Middle fossa approach, Suboccipital approach, Retrosigmoid approach, Retrolabyrinthine approach. Intratympanic injections of aminoglycoside -Streptomycin: not used now due to high risk of HL -Gentamicin: Angular vestibulo -ocular reflex (rapid head thrusts) by excitation of SCC on treated side is reduced. Seventy to ninety percent patients have complete control of vertigo. C) Microwick : A microwick of polyvinyl acetate is passed through the grommet. When gentamicin or steroid drops are instilled in the ear, microwick soaks it and delivers the same to the round window.

27. Non hearing conservative vestibular ablative surgery Labyrinthectomy: Vestibular neuroepithelium is removed. It is the best reliable surgery to get relief from vertigo due to Ménière’s disease but is indicated when serviceable hearing is absent. Done by using Ablation with hypertonic saline or Transcanal approach or Transmastoid approach Translabyrinthine cochleovestibular neurectomy Destruction of Scarpa’s ganglion