Sudden Sensorineural Hearing loss Ent.pptx

ENT AND HEAD NECK SURGERY

1. Sudden Sensorineural Hearing loss Dr. Dinesh Shrestha 1st year resident, ENT-HNS Pokhara Academy of Health Sciences

2. Overview Introduction Definition Causes Clinical assessment Prognosis Treatment Outcome assessment Conclusion

3. Introduction Otological emergency Definitive aetiology and treatment controversial Annual incidence: 5-30 per 100000 population Unilateral: 99% Idiopathic: Causes identified in 5-10% cases Spontaneous recovery rate of 32-65% Highest incidence :50-60 years No sex preponderance

4. Definition First described by De kleyn in 1944 A.D Definition: Sudden hearing loss- rapid onset, occuring over <72 hours period, hearing impairment of one or both ear Audiometric criteria:>30 dB sensorineural loss in atleast 3 consecutive frequencies Idiopathic sudden sensorial hearing loss- SSNHL with no identifiable cause

5. Causes of SSNHL Infectious : Meningococcal meningitis, Encephalitis, Herpes virus, Mumps, measles, HIV, lymes disease, Rubella, Syphillis , Toxoplasmosis Traumatic : Barotrauma, Perilymh fistula, Intense noise exposure, temporal bone fracture Ear surgery (Stapedectomy)

6. Causes of SSNHL Neoplastic: Cerebellopontine Angle Tumor, leukemia, Myeloma Autoimmune : Wegner’s granulomatosis, Rheumatoid arthritis, Sjogren Syndrome , Polyarteritis nodosa, SLE, Relapsing polychondritis , Cogan’s syndrome, Autoimmune inner ear disease

7. Causes of SSNHL Toxic: Aminoglycosides, loop diuretics, NSAIDs, Salicylates, General Anaesthesia Circulatory: Vertebrobasilar insufficiency, vascular disease with mitrochondropathy , red blood cell deformability, sickle cell disease, cardiopulmonary bypass

8. Causes of SSNHL Neurologic : Multiple sclerosis, focal pontine ischemia, Migraine Metabolic: Hyperlipidemia, thyrotoxicosis, Diabetes

9. Idiopathic Sensorineural Hearing Loss Postulated causes: Viral Infection Vascular occlusion Intracochlear membrane rupture Autoimmune inner ear disease

10. Viral theory Current belief- viral cochleitis causes major cases of ISSNHL Wilson et. al. Statistically significant seroconversion in patient with ISSNHL(63%) for Cytomegalovirus Influenza B Mumps Rubella Varicella

11. Viral theory Examination of temporal bone: Histopathological evidence consistent with viral infection Loss of neuron in apical spiral ganglion Animal experiment: Viral penetration of inner cells Isolation of virus and viral antigen in perilymph

12. Vascular theory Cochlea supplied by end artery- susceptible to damage by vascular occlusion Change in blood viscosity – Cochlear ischemia Animal experiment: Cochlear fibrosis and inner ear ossification Abnormal circulatory states : Sickle cell anaemia Waldenstrom macroglobulinemia AICA strokes Cardiopulmonary bypass

13. Intracochlear membrane rupture Rupture of intracochlear membrane Coincidental Studies of temporal bone : No evidence of Reissner or basilar membrane rupture

14. Autoimmune theory Immunopreviliged - separated by blood labyrinthine barrier Immunoglobulin found in the perilymph SNHL reported in systemic autoimmune disorder: Wegener’s granulomatosis Rheumatoid arthritis Polyarteritis nodosum Sjogren’s syndrome Cogan’s syndrome Lupus erythematosus Relapsing perichondritis

15. Autoimmune inner ear disease (AIED) Described by Mc Cabe in 1979. Bilateral rapidly progressive SNHL, responsive to steroids or cytotoxic drugs Cause thought to be antibodies or immune cells No other systemic manifestation of autoimmune disorder Serology: antibody to 68 – kDa protein(35%) Treatment Prednisone 1mg/Kg/day for 4 weeks If relapse during taper – Cytotoxic agent s/a Methotrexate Cyclophosphamide

16. Clinical assessment History Examination Investigations

17. History Onset of hearing loss Sudden onset of aural blockage or fullness Premorbid hearing level Unilateral or bilateral Associated symptoms : Tinnitus Vertigo (30-40%) Dizziness Aural fullness History of trauma,straining , diving , flying and intense noise exposure Previous ear surgery, ototoxicity

18. Examination Head and neck examination Otoscopic examination: exclude middle ear effusion, infection or cholesteatoma, Wax impaction Tuning fork test Fistula test Neurological examination

19. Investigations Audiometry MRI scan with gadolinium enhancement Fine cut CT scan

20. Investigations Complete blood count ESR Urea and electrolyte Lipid profile Glucose Thyroid function test Clotting screen VDRL Serology for lymes disease Autoantibodies

21. Prognosis Time since onset Age Vertigo Audiogram

22. Prognosis Age - Children and adults > 40 yrs have a poorer prognosis.

23. Prognosis Presence of vertigo – poor prognosis. 29% of patient with vertigo recovered compared to 55% without vertigo ( Byl , 1984 ; n = 225 )

24. Prognosis Time since onset – 56% presenting within 7 days recovered 27% who presented > 30 days later

25. Prognosis Severity of loss more severe the loss, poorer is the prognosis profound losses : exceptionally poor prognosis

26. Prognosis Shape of audiogram Up sloping and mid-frequency losses recover more frequently than down sloping and flat losses

27. Prognosis Tinnitus Apparently does not affect outcome Danio et al. ( 1984 ) found it to be favorable prognostic sign ESR Other co-morbid factors

28. Treatment

29. Systemic steroid Widely used as standard therapy Significant recovery of hearing with hearing loss of 40-90 dB (Wilson et. Al.) Cinamon et. al : Compared treatment with prednisolone, placebo, carbogen and room air No significant difference Nosrati and Zarone : Randomised , triple blinded, placebo controlled trial No significant difference in hearing

30. Oral steroid Dose: Oral Prednisolone : single dose of 1mg/kg/day-10-14 days Complication of oral steroid

31. Intratympanic Steroids represent a safe and effective treatment of SSNHL. Administration of steroids to middle ear round window niche/membrane directly targeting inner ear Very little systemic absorption May benefit patients for whom systemic steroids are contraindicated Higher concentration to end organ

32. Intratympanic Steroids Advantages May be used when systemic steroids are contraindicated or refused Greater concentration achieved at target end organ May be performed in outpatient setting Possible use for salvage of hearing Relatively low complication rate

33. Intra tympanic steroid Choice of steroid: Dexamethasone :10-24 mg/ml Solumedrol- 30-40 mg/ml Use of facilitator: Histamine and hyaluronic acid Frequency and Injection technique: Self administration several times a day or clinician administration(Consecutive day or weekly) Technique: Spinal needle on syringe, grommet, microwick , hydrogel application,

34. Complication of Intratympanic steroid Pain Transient dizziness Persistent tympanic perforation Vasovagal attack

35. Hyperbaric oxygen therapy Delivers 100% oxygen at pressure more than 1 atmosphere Results : increase tissue oxygenation Potentiates response to infection and ischemia Cochrane reviewed 7 randomized clinical trial People with early presentation- significantly improved hearing loss Improvement is related with severity of hearing loss

36. Complications of HBOT Damages to ear, lungs and sinuses Temporary worsening of short sitedness Claustrophobia Oxygen poisioning Eustachian tube dysfunction

37. Disadvantages of HBOT Expensive Time consuming Involves multiple sessions

38. Salvage treatment Patient refractory to oral steroid Both HBOT and Intratympanic steroids used Improved hearing outcomes after Intratympanic therapy (8-100%) Dexamethasone > Methylprednisolone Injection >round window catheter

39. Outcome assessment Audiological assessment in each follow up Reveal other aetiology Identify ongoing hearing loss Determine the benefit of given treatment Suitability for salvage treatment Method: pure tone audiometry Speech recognition threshold Word recognition Score

40. Definition of Recovery and improvement Complete: Follow up PTA or SRT improved to within 10 dB of presudden hearing loss Partial: Follow up PTA or SRT improved to 50% presudden hearing loss No recovery: <50% of recovery of presudden hearing loss

41. American association recommendation for outcome assessment Uaffected ear used as standard to compare the recovery Complete recovery- returns within 10 dB HL of unaffected ear Partial recovery: whether or not degree of initial hearing loss rendered ear non serviceable <10 dB HL improvement – No recovery

42. Conclusion SSNHL is an otologic emergency Minimal data for understanding its etiology and definite treatment Treatment is controversial Better prognosis if treatment started early

43. References Scott-Brown’s Otorhinolaryngology head and neck surgery, 8th edition Volume 2

44. Next presentation Topic: Presenter: Dr. Satish Kumar Ray Day: Tuesday