Download Sudden sensori-neural deafness

Sudden
sensori-neural
hearing loss
Dr. Vishal Sharma
Defining triad (Wilson, 1980)
1. Sensori-neural deafness of > 30 dB HL
2. over > 3 contiguous frequencies
3. occurring in < 3 days
– Within 12 hrs: Cummings
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
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%)
Age (years)
Distribution in 1220 cases
(Shaia & Sheehy, 1976)
< 30
13 %
30 – 39
13 %
40 – 49
21 %
50 – 59
22 %
60 – 69
18 %
> 70
13 %
Etiology
1. Idiopathic (single largest group: 90 - 95%)
2. Cochlear causes
3. Retro-cochlear causes
4. Miscellaneous
• Psychogenic
• Malingering
Criteria for idiopathic
SSNHL
• SSNHL present
• No other cranial nerve involvement except
eighth cranial nerve
• No other etiology is known
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
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
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
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
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
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
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
Retro-Cochlear causes
• Meningitis
• Encephalitis
• Tumor: Vestibular schwannoma, other tumors
of cerebello-pontine angle
• Multiple sclerosis
• Metastasis
Clinical Features
• Medical Emergency
• Sensori-neural hearing loss
• Tinnitus: seen in 60 - 70% pt
• Vertigo: seen in 20 - 40% pt
• Aural fullness: seen in 15 - 30% pt
• Viral URTI: seen in 20 - 40% pt
Patient Evaluation
• 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
Basic Laboratory
Investigations
1. Complete Blood Count + ESR: for infection
2. BT, CT, PT, aPTT & INR: for bleeding disorder
3. VDRL, FTA-Abs, TPHA, TPI: for syphilis
4. ANA, Rh factor, other auto-antibody titre
5. T3, T4, TSH: for hypothyroidism
6. FBS & PPBS: for diabetes mellitus
7. Fasting lipid profile: for hyperlipidemia
8. Urea & Creatinine: for renal failure
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)
Contrast M.R.I.: acoustic neuroma
Mondini dysplasia
sac-like cochlea
(black arrow)
amorphous vestibule
without any defined
semicircular canals
(white arrow)
enlarged vestibular
aqueduct (red arrow)
Enlarged vestibular aqueduct
Audiometry
• Pure-tone Audiometry
• Speech Audiometry
• Tympanometry & acoustic reflex tests
• SISI & Tone Decay Test
• Oto-acoustic emission
• BERA
• 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 & 500
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;103:1145-49.
• 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
Treatment
Treatment options
(a) Vasodilators
(b) Rheologic agents
(c) Anti-inflammatory agents (Steroids)
(d) Anti-viral agents
(e) Diuretics
(f) Hyperbaric oxygen
(g) Surgery
General Treatment
1. Bed rest & avoid strenuous exercise
2. Avoid following aggravators:
 Alcohol
 Smoking
 Stress
 Sleep deprivation
 CNS stimulants
 Fatty diet
 Straining
 Loud noise
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
30 min, 8 times / day at 1 hour intervals in O.T.
• Nimodipine: 30 mg BD-TID, PO for 3 wk
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: 500-1000 ml/d X 7d
• Anticoagulants (heparin & warfarin): obsolete
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
Grommet in P.I.Q.
Post-steroid recovery
Side-effects of Steroids
• Hyperglycemia
• Hypertension
• Gastric ulceration
• Osteoporosis
• Flaring of infection & delayed wound healing
• Psychiatric disturbance (insomnia, euphoria)
• Weight gain & trunk obesity
Anti-virals & Diuretics
• Anti-virals
• 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
Hyperbaric oxygen
• Consists of exposure to 100% oxygen at
pressure of 250 kPa for 60 minutes in a multiplace hyperbaric chamber along with high
doses of gluco-corticoids
• Best results achieved if treatment started
early
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
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
Result evaluation
• Patient with pre-SSNHL value of:
• Pure Tone Average = 30 dB
• Speech Reception Threshold = 30 dB
• Complete recovery: PTA or SRT  30 - 40 dB
• Partial recovery: PTA or SRT  41 - 45 dB
• No recovery: PTA or SRT  > 45 dB
Spontaneous Recovery
• Spontaneous recovery rates for SSNHL range
from 47 - 70%, combining categories of
complete & partial recovery
• Most spontaneous recoveries occur within 2
weeks
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 = 40 - 60%
Favorable prognosis
1. Tx starting <10 days after onset of SSHL
2. Mild to moderate SNHL
3. Low or mid frequency SNHL
4. Presence of tinnitus (doubtful significance)
Unfavorable prognosis
1. High frequency deafness (especially 8 kHz)
2. Hearing loss > 90 dB HL
3. Vertigo / vestibular changes evident on ENG
4. Bilateral sensori-neural deafness
5. Tx starting >15 days after onset of deafness
6. Age < 15 years or > 65 years
7. Elevated ESR (>25)
8. Poor speech discrimination score
Further Study
• 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: 791-798,
• Wilson W. et al. (1980) The efficacy of steroids in the
treatment of ISSNHL. Arch. Otolaryngol. 106, 772–776
Thank You