1. Sudden sensori-neural hearing loss
Dr. Vishal Sharma

2. Defining triad (Wilson, 1980)
Sensori-neural deafness of > 30 dB HL
over > 3 contiguous frequencies
occurring in < 3 days
Within 12 hrs: Cummings

3. Synonyms & alternatives
Sudden sensorineural hearing loss is also called acute cochlear dysfunction
Sudden sensorineural hearing loss accompanied by acute vertigo is also called acute cochleo-vestibular dysfunction
Deafness occuring over days or weeks is called rapidly progressive hearing loss

4. Epidemiology Annual incidence (USA) is 5 - 20 cases / 1 lakh
47-70 % resolve spontaneously (do not report)
True incidence rate is higher
Gender not a risk factor
Unilateral cases: 96-99%
Bilateral cases: 1-4%
Left ears are affected more (55%)

5. Distribution in 1220 cases (Shaia & Sheehy, 1976)
Age (years)
Distribution in 1220 cases (Shaia & Sheehy, 1976)
< 30
13 %
30 – 39
40 – 49
21 %
50 – 59
22 %
60 – 69
18 %
> 70

6. Etiology Idiopathic (single largest group: 90 - 95%) Cochlear causes
Retro-cochlear causes
Miscellaneous
Psychogenic
Malingering

7. Criteria for idiopathic SSNHL
SSNHL present
No other cranial nerve involvement except eighth cranial nerve
No other etiology is known

8. Idiopathic SSNHL Various hypotheses are:
1. Labyrinthine viral infection (viral cochleitis)
2. Labyrinthine vascular compromise
3. Membrane rupture
4. Immune-mediated inner ear damage
5. Activation of cochlear nuclear factor kappa B

9. 1. Labyrinthine viral Infection (20 – 40 %)
Herpes, mumps, measles, maternal rubella, cytomegalovirus, varicella zoster
2. Labyrinthine vascular compromise
caused by thrombosis, embolus, reduced blood flow, vasospasm
Western diet (rich in saturated fat), alcohol intake & tobacco smoking are predisposing factors

10. 3. Membrane rupture (Simmons)
Pts hear pop sound before sudden deafness
Oval & round window perilymph fistulae leak perilymph into middle ear  low perilymph pressure & relative endolymphatic hydrops
Rupture of intra-cochlear membranes  mixing of perilymph & endolymph  altering endo-cochlear potential

11. 4. Immune-mediated inner ear damage
Antigen-antibody complex mediated destruction of cochlea
Cross-reacting circulating antibodies seen in 65 % pt of SSNHL. Associated conditions are:
 Cogan syndrome  Relapsing polychondritis
 Systemic lupus erythematosus
 Polyarteritis nodosa  Temporal arteritis

12. 5. Activation of cochlear nuclear factor kappa B
Merchant et al (2005) proposed this new theory
Nuclear factor kappa B (NFҚ B) functions by:
 regulating inflammatory response + apoptosis
 regulating intracellular Ca & neuronal excito-toxicity
NFҚ B activation is associated with destruction of spiral ganglion neurons & cochlear hair cells causing ISSNHL

13. Cochlear causes
1. Infection: bacterial, viral, spirochaetal, mycoplasma
2. Trauma: temporal bone #, acoustic trauma, barotraumas, perilymph fistula, radiotherapy
3. Vascular: hyper-coagulable states, thrombo embolism, hypertension, migraine
4. Hematological: polycythemia, leukemia, anemia

14. Cochlear causes
5. Oto-toxicity: aminoglycoside, aspirin, frusemide, antimalarials, cisplatin
6. Endolymphatic hydrops
7. Metabolic: diabetes mellitus, hypothyroidism, hyperlipidemia, renal failure
8. Auto-immune: Cogan syndrome, systemic lupus erythematosus, relapsing polychondritis

15. Retro-Cochlear causes
Meningitis
Encephalitis
Tumor: Vestibular schwannoma, other tumors of cerebello-pontine angle
Multiple sclerosis
Metastasis

16. Clinical Features Medical Emergency Sensori-neural hearing loss
Tinnitus: seen in % pt
Vertigo: seen in % pt
Aural fullness: seen in % pt
Viral URTI: seen in % pt

17. Patient Evaluation

18. Early diagnosis & Tx improves prognosis
Deafness: onset, duration, severity, previous HL
Associated vertigo / tinnitus / aural fullness
Exclude trauma (noise / baro / temporal bone #)
Exclude ototoxicity / DM / hypothyroidism / blood dyscrasia / hyperlipidemia / renal failure
Tuning fork tests & fistula test
Perform careful neurological examination

19. Basic Laboratory Investigations

20. Complete Blood Count + ESR: for infection
BT, CT, PT, aPTT & INR: for bleeding disorder
VDRL, FTA-Abs, TPHA, TPI: for syphilis
ANA, Rh factor, other auto-antibody titre
T3, T4, TSH: for hypothyroidism
FBS & PPBS: for diabetes mellitus
Fasting lipid profile: for hyperlipidemia
Urea & Creatinine: for renal failure

21. Imaging Studies 1. MRI with gadolinium contrast (gold standard):
 1-2% pt with ISSNHL have IAC or CPA tumors
 3-12% pt with acoustic neuroma have SSNHL
2. CT scan temporal bone + contrast
Detect anatomic defects (Mondini dysplasia or enlarged vestibular aqueduct syndrome)

22. Contrast M.R.I.: acoustic neuroma

23. Mondini dysplasia sac-like cochlea (black arrow)
amorphous vestibule without any defined semicircular canals (white arrow)
enlarged vestibular aqueduct (red arrow)

24. Enlarged vestibular aqueduct

25. Audiometry Pure-tone Audiometry Speech Audiometry
Tympanometry & acoustic reflex tests
SISI & Tone Decay Test
Oto-acoustic emission
BERA

26. High-frequency hearing loss: PTA at 4 & 8 kHz
High-frequency hearing loss: PTA at 4 & 8 kHz exceeds PTA at 250 & 500 Hz by > 30 dB
Low-frequency hearing loss: PTA at 250 & Hz exceeds PTA at 4 & 8 kHz by > 30 dB
Flat-type hearing loss: equal hearing losses at each frequency
Profound hearing loss: no response at maximum intensity for > 2 frequencies
Reference : Nakashima T, et al. Laryngoscope 1993;103:

27. Presence of OAE indicates preservation of some outer hair cell function
ABR reflects function of neural pathways
ABR & OAE results also assist in diagnosing psychogenic hearing loss & malingering
Vestibular tests are obtained when indicated by history & physical examination

28. Treatment

29. Treatment options (a) Vasodilators (b) Rheologic agents
(c) Anti-inflammatory agents (Steroids)
(d) Anti-viral agents
(e) Diuretics
(f) Hyperbaric oxygen
(g) Surgery

30. General Treatment Bed rest & avoid strenuous exercise
Avoid following aggravators:
 Alcohol  Smoking
 Stress  Sleep deprivation
 CNS stimulants  Fatty diet
 Straining  Loud noise

31. Vasodilators: reverse hypoxia
Betahistine: 16 mg TID, PO for 3 wk
Xanthinol nicotinate: 300 mg slow IV Q12H
 500 mg BD, PO for 3 wk
Carbogen (5% CO2 + 95% O2) inhalation: for min, 8 times / day at 1 hour intervals in O.T.
Nimodipine: 30 mg BD-TID, PO for 3 wk

32. Rheologic Agents  blood viscosity to  blood flow & O2 delivery
Low-molecular-weight dextran: 10 ml / kg / d X 7d
Pentoxifylline: 400 mg TID, PO for 3-4 wk
Diatrizoate meglumine infusion: 40 ml/d X 7d
Hydroxy-ethyl starch: ml/d X 7d
Anticoagulants (heparin & warfarin): obsolete

33. Cortico-Steroids Anti-inflammatory agents
Prednisolone: 1mg / kg / d in single or divided doses for 10 d  taper over 3 weeks
Intratympanic dexamethasone solution (8 mg/mL): 0.3–0.4 mL with hyaluronidase on alternate days after grommet insertion in PIQ

34. Grommet in P.I.Q.

36. Post-steroid recovery

37. Side-effects of Steroids
Hyperglycemia
Hypertension
Gastric ulceration
Osteoporosis
Flaring of infection & delayed wound healing
Psychiatric disturbance (insomnia, euphoria)
Weight gain & trunk obesity

38. Anti-virals & Diuretics
Acyclovir: 800 mg PO, 5 times / day for 7 days
Famciclovir: 250 mg PO, TID for 7 days
Diuretics
Used in SSNHL due to endolymphatic hydrops
Hydrochlorothiazide: 25 mg PO, BD for 3-4 wk

39. Hyperbaric oxygen
Consists of exposure to 100% oxygen at pressure of 250 kPa for 60 minutes in a multi-place hyperbaric chamber along with high doses of gluco-corticoids
Best results achieved if treatment started early

40. Surgery
Repair of oval & round window perilymph fistulae has been used in cases of ISSNHL associated with positive fistula test or history of recent trauma or barotrauma
No standard methods are detailed

41. Result evaluation (Wilson)
Complete recovery:
PTA or SRT: < 10 dB of pre-SSNHL value
Partial recovery:
PTA / SRT: > 50% recovery of pre-SSNHL value
No recovery:
PTA / SRT: < 50% recovery of pre-SSNHL value

42. Result evaluation Patient with pre-SSNHL value of:
Pure Tone Average = 30 dB
Speech Reception Threshold = 30 dB
Complete recovery: PTA or SRT  dB
Partial recovery: PTA or SRT  dB
No recovery: PTA or SRT  > 45 dB

43. Spontaneous Recovery
Spontaneous recovery rates for SSNHL range from %, combining categories of complete & partial recovery
Most spontaneous recoveries occur within 2 weeks

44. Results
No high-quality, randomized, controlled trial shows efficacy of any medical therapy
Most studies don't show significant beneficial effect of vasodilators, acyclovir, rheological agents, hyperbaric oxygen over placebo
Corticosteroid therapy is only accepted therapy for ISSNHL. Recovery rates = %

45. Favorable prognosis Tx starting <10 days after onset of SSHL
Mild to moderate SNHL
Low or mid frequency SNHL
Presence of tinnitus (doubtful significance)

46. Unfavorable prognosis
High frequency deafness (especially 8 kHz)
Hearing loss > 90 dB HL
Vertigo / vestibular changes evident on ENG
Bilateral sensori-neural deafness
Tx starting >15 days after onset of deafness
Age < 15 years or > 65 years
Elevated ESR (>25)
Poor speech discrimination score

47. Further Study

48. Leong, A.C. et al. (2007). Sudden hearing loss - A 12 minute consultation. Clinical Otolaryngology. 32: 391–394
Xenellis J. et al. (2006). Idiopathic sudden sensorineural hearing loss: prognostic factors. J.L.O. 120, 718–724
Xenellis J. et al. (2006) Intra-tympanic steroid treatment in ISSNHL. Otolaryngol. Head Neck Surg. 134, 940–945
Aoki D. et al. (2006) Evaluation of superhigh-dose steroid for SSNHL. Otolaryngol. Head Neck Surg. 134, 783–787
Bennett M. et al. (2005) Hyperbaric oxygen therapy for ISSNHL & tinnitus: J. Laryngol. Otol. 119: ,
Wilson W. et al. (1980) The efficacy of steroids in the treatment of ISSNHL. Arch. Otolaryngol. 106, 772–776

49. Thank You