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Medical Management of Vestibular Disorders

Medical Management of Vestibular Disorders. Dr. W. WATAD. Introduction. Basic inputs – Vision - ocular stability Proprioception - gait control Vestibular system - balance Disorders of vestibular system are major disruptors causing spatial disorientation

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Medical Management of Vestibular Disorders

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  1. Medical Management of Vestibular Disorders Dr. W. WATAD

  2. Introduction • Basic inputs – • Vision - ocular stability • Proprioception - gait control • Vestibular system - balance • Disorders of vestibular system are major disruptors causing spatial disorientation • Vestibular DD has remained stable over the past several decades, but the management strategies continue to improve

  3. The Goal • To review and discuss the medical management of vestibular disorders

  4. Pathophysiology • Vestibular labyrinth - detects linear and angular head movements • Semicircular canals - angular • Hair cells - cupula • Otolithic organs (utricle, sacule) - linear • Hair cells - macula

  5. Vestibular nerve - superior, inferior • Afferent nerve fibers are bipolar • cell bodies lie within Scarpa’s ganglion

  6. pathophysiology

  7. Pathophysiology • Balance requires – • Normal functioning vestibular system • Input from visual system (vestibulo-ocular) • Input from proprioceptive system (vestibulo-spinal) • Disruption of balance between inputs results in : • vertigo (acute) • disequilibrium (chronic)

  8. Pathophysiology

  9. Central causes of vestibular dysfunction compromise central circuits that mediate vestibular influences on posture, gaze control, and autonomic function : • nausea, vomiting • Pallor • Respiratory/circulatory changes • Goal of treatment: restore balance between different inputs

  10. Medical Treatment • Symptomatic : • Relieve acute symptoms , autonomic complaints • Specific therapy : • Targeting the underlying cause of vertigo

  11. Symptomatic Pharmacotherapy • Predominant targeted vestibular neurotransmitters: • Cholinergic • Histaminergic • GABA neurotransmitters - negative inhibition • Vomiting center transmitters: • Dopaminergic (D2) • Histaminergic (H1) • Serotonergic (5-HT3) • Multiple classes of drugs effective

  12. Symptomatic Pharmacotherapy • Main classes : • Antihistaminergic - dimenhydrinate • Anticholinergics - scopolamine, meclizine • Anti-dopaminergic - droperidol • (gamma)-aminobutyric acid enhancing (GABA-ergic) agents - lorazepam, valium • Reduce the severity of vestibular symptoms

  13. Symptomatic Pharmacotherapy

  14. Suppressant agents : • Anticholinergics • Antihistamines • Benzodiazepines • Anti-emetic drugs

  15. anticholinergics • Inhibit stimulation ( exessive impulses ) from peripheral organs – vestibular n. • Inhibit transmission in LVN ( lat. Vestibular Nucleus ) • Non-specific muscarine receptor antagonist • Reversible overcompensation

  16. Agents not cross BBB are ineffective • Ineffective after symptoms have appeared • Scopalamine / atropine • SE : • Dry mouth dilated pupils • Urinary retention sedation • Constipation confusion • C/I : BPH , closed angle glaucoma

  17. antihistamines • Uncertain mechanism • Central effect ( block H1-R) • Inhibiton synaptic transmission on MVN ( medial vestibular nucleus ) • Anticholinergic and sedative effects • Effective also after symptomes have appeared • Cinnarazine • promethazine / diphenhydramine - sedative • prochlorperazine / miclizine - antiemetic

  18. benzodiazepines • GABA modulators • Central suppression of vestibular response • Sedative , hypnotic, muscle relaxant , reduce anxiety • Clonazepam / lorazepam / alprazolam • SE : • Impaired vestibular compensation • Impaired memory • addiction

  19. Anti emetics • Dopamine block activity • Not ideal for emesis from vestibular imbalance • Antihistamine effect – promethazine ( H1-R block) • Metoclopramide – potent central antiemetic, speed gastric emptying is not effective antivertigo drug

  20. Sulpiride : • Selective dopamine (D2) antagonist • Low incidence of extrapyramidal • Antiemetic action • Improve blood flow, mucosal secretion in GI • Antivertigo , anti-migraine headache • Antidepressant activity ( low doses ) • Antipsychotic activity ( high doses )

  21. New antiemetic – 5-HT3 antagonist serotonin ( 5 hydroxytryptamine subtype 3 receptor ) antagonist • Ondensetron / granisetron • Nausea and vomiting associated with chemotherapy , post. Operation • Less effective for vestibular emesis • High cost

  22. Other options • Ca channel blockers : • Vestibular suppression on Ca channel in hair cells • Flurnarazine / cinnarazine • Antihistamines and anticholinergic activity • Effective in menier’s and migrane • SE : sedation , weight gain , parkinsonism

  23. Na channel blocker : • Affect GABA NT , glutamate antagonist • Phenytoin / nerontin / tegretol • Central nystagmus • Anticonvulsants are promising agents for treatment vertigo ( uncertain mechanism )

  24. Histamine agonist : • Betahistine – H1/H3 – R agonist • Increase circulation to inner ear • Suppress veastibular function • Facilitation of compensation • SE : nausea , headache • Caution ; peptic dis , pheochromocytoma

  25. Steroids • Reduce duration of vertigo episodes • Effective in meniere’s , vestibular neuritis • Sypmpathomimetics • Counterbalance sedative effect of vestibular suppressant - increase compensation • Ephedrine / amphetamine – limitted use

  26. Acetyl- leucine • Vestibular suppresant • Rapid antivertigo effect ( IV) • Ginkgo-Biloba • Vestibular suppresant • Effective in tinnitus , improve memory

  27. Selective Ach antagonist • M2-R antagonist • Vestibular suppressant without SE • Little reaserch

  28. Alternative medicine agents • Ambra grisea D6 • Anamirta cocculus D4 • Conium maculatum D3 • Petroleum rectificatum D8

  29. Specific Pharmacotherapy • Vestibular Neuritis * • Meniere’s Disease * • Benign Paroxysmal Positional Vertigo * • Otosyphilis • Vertebrobasilar Insufficiency • Migraine (with vertigo) * more common

  30. Vestibular Neuritis • Sudden onset of peripheral vertigo • Inflammation of vestibular nerve - presumably of viral origin • Spontaneous, complete symptomatic recovery with supportive treatment • Treatment aimed at stopping inflammation

  31. Vestibular Neuritis • Ariyasu et al. (1990) • 20 patients: double-blinded, crossover • Methylprednisolone vs. placebo • 90% decrease in vertigo within 24 hours vs. 30% of placebo group • Placebo switched to steroid after 24 hours with decrease in vertigo over next 24 hours • 16 patients receiving steroid with resolution had normal ENG within one month

  32. Meniere’s Disease • Hallpike and Cairns - 1938 found endolymphatic hydrops by histology • Precise etiology is unknown

  33. Meniere’s Disease • Widely accepted medical treatment • Dietary salt restriction • Diuretics • Thiazide diuretics • Decrease Na absorption is distal tubule • Side effects - hypokalemia, hypotension, hyperuricemia, hyperlipoproteinemia • Combination potassium sparing agents spironolactone , thiazide + amiloride

  34. Meniere’s Disease • At least 3 months of diuretic therapy recommended before discontinuing • Sulfa allergies - can try loop diuretics or alternate therapies

  35. Meniere’s Disease • Carbonic anhydrase inhibitors (acetazolamide) • “inner ear glaucoma” • Decreased Na-H exchange in tubule • Decreased CSF production • Diuretic effect not as long-lasting • Side effects - nephrocalcinosis, mild metabolic acidosis, GI disturbances

  36. Meniere’s Disease • Vasodilators • Based on hypothesis - pathogenesis results from ischemia of stria vascularis • Rationale - improve metabolic function • IV histamine, ISDN, cinnarizine (CA antagonist), betahistine (oral histamine analogue) • Anecdotal success • No demonstrated beneficial effects in studies

  37. Meniere’s Disease • Newer theories • Multifactorial inheritance • Immune-mediated phenomena • Association of allergies • Study by Gottschlich et al. • 50% meeting criteria have antibodies to 70-kD heat-shock protein • 70-kD HSP implicated in AI-SNHL

  38. Meniere’s Disease • Immunosuppressive agents gaining favor • Systemic and intra-tympanic glucocorticoids • Cyclophosphamide • Methotrexate • Shea study - intractable Meniere’s • 48 patients IT dexamethasone • 66.7% elimination of vertigo • 35.4% improvement in hearing (>10dB and/or 15% change in word recognition score)

  39. Meniere’s Disease • Chemical labyrinthectomy • Disabling vertigo • After trial of adequate medical therapy • Intratympanic aminoglycoside (ITAG) • Allows treatment of unilateral disease • Gentamicin • Primarily vestibulotoxic • may impair vestibular dark cells (endolymph) • Inherent hearing loss risk - 30%

  40. ITAG • Stock solution - 40mg/mL gentamicin • 10 to 20 mg injected over round window • Patient supine, ear up for 30 minutes • Instructed not to swallow • Bolus injections - weekly or bi-weekly • End point variable - vestibular hypofunction • Audiometry monitoring between injections • Total vestibular ablation not necessary

  41. ITAG • Minor • 91% control of vertigo • 3% rate of profound SNHL (usually sudden) • 22% recurrence rate • Continuous delivery • Microwick • Round Window Microcatheter • Direct injection (labyrinthotomy) • Significant hearing loss • Out of favor

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

  43. BPPV • Treatment approaches • Liberatory maneuvers • Particle repositioning • Habituation exercises

  44. BPPV • Epley • Canalithiasis • Canalith repositioning • Move into vestibule • Cure rates • 80% - one treatment • 100% - multiple

  45. Otosyphilis • Penicillin established treatment • IM and IV routes acceptable • IM - 2.4 million units benzathine PCN weekly x 3 consecutive weeks is minimal treatment (some advocate up to 1 year) • IV - 10 million units PCN G qD in divided doses x 10 days, followed by 2.4 million units benzathine PCN x 2 weeks

  46. 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 inhibitor • Risk of life-threatening neutropenia • Only in patients unable to tolerate aspirin

  47. Migraine • Concomitant vertigo and disequilibrium • Headache control improves vertigo • Diagnostic criteria • Personal/family history • Motion intolerance • Vestibular symptoms - do not fit other causes • Theories - vascular origin, abnormal neural activity (brainstem), abnormal voltage-gated calcium channel genes

  48. Migraine • Treatment • Modifying risk factors • Exercise and diet • Avoid nicotine, caffeine, red wine and chocolate • Abortive medical therapy • Ergots • Sumatriptin • Midrin • Prophylactic medical therapy • B blockers, Ca channel blockers, NSAIDs, amitryptiline, and lithium

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