Sudden Idiopathic Hearing Loss

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Sudden Idiopathic Hearing Loss

• Molly Simpson and Beth Burlage

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Definition - Distinction needed

• Idiopathic Hearing Loss(ISSHL)- Perceptive
  hearing loss, etiology remains unknown after
  clinical, laboratory and imaging studies, hearing
  loss occurred within 24 hours, hearing loss is
  nonfluctuating, severity of the hearing loss
  averages at least 30 dB HL for three subsequent
  one octave steps in frequency, blank otological
  history in an otherwise healthy individual
• Sudden Hearing Loss (SSHL) - a sensorineural
  hearing loss of 30 dB over less than three days
  affecting three contiguous frequencies, symptom
  of a greater condition

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Symptoms

• Unilateral (only 2 of cases experience bilateral
  deafness)
• Roaring tinnitus
• Short- lived dysequilibrium/vertigo

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Audiometry Examples

• Possible Slopes of HL
• Low Frequency
• Low through Mid-High Frequency
• High Frequency - downward sloping loss has a
  worse prognosis than low and mid-frequency loss

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Causes

• The term idiopathic indicates an unknown origin
• Research suggests SSHL etiology as
• Compromised Vascular Supply
• Intracochlear Membrane Breaks, Perilymph Fistula
• Neurologic lesions
• Viral Infections
• Traumatic insults
• Autoimmune Inner Ear Disease
• Enlarged Vestibular Acqueduct Syndrome
• Syphillis

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Diagnosis

• ISSHL can often be mistakenly diagnosed as a
  middle ear disorder
• Testing will reveal
• Normal Tympanometry Abnormal Reflexes
• Tuning fork tests will indicate a sensorineural
  loss
• OAE/ABR abnormal
• Audiometry will usually show a unilateral loss
• CT Scan/MRI needed to rule out neuroma
• Negative fistula test
• Urinalysis, blood work

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Treatment

• Depends on identification of lesion
• Vascular
• Hyperbaric oxygen therapy (HBOT) involves
  breathing pure oxygen in a specially designed
  chamber and it is sometimes used as a treatment
  to increase the supply of oxygen to the ear and
  brain in an attempt to reduce the severity of
  hearing loss
• Carbogen treatment 95 oxygen and 5 carbon
  dioxide. Carbogen inhalation therapy is given for
  about 10 minutes each 68 hours over a three-day
  period by a respiratory therapist. This treatment
  is thought to increase the oxygen in the
  perilymph by dilating the cochlear artery
• These treatment routes may not be covered by
  insurances

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Treatment, cont.

• Structural defects may require surgical treatment
• Fistulas
• Acoustic neuromas

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Treatment, cont.

• If no site of lesion is found, aggressive steroid
  treatment is usually prescribed
• Prednisone 1mg/kg per day for 24 weeks, rapidly
  tapering the drug if there is a complete recovery
  of hearing. If hearing does not recover,
  reduction of medication is slowed.
• The best outcome when steroids are administered
  as quickly as possible
• Some may benefit from antivirals, diuretics, a
  low-sodium diet, a restriction in the use of
  stimulants, (alcohol and tobacco) and avoidance
  of excessive physical activity and noise
  exposure.

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Treatment, cont.

• 35-50 of people have hearing return to normal
  levels
• If the hearing does not return, hearing aids,
  cochlear implants or assistive listening devices
  may be prescribed
• ASHA recommends a multi-memory, digitally
  programmable hearing aid, or with a volume wheel
  for flexibility.

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Prevention

• Most studies find no seasonal, geographic,
  ethnic, racial or sexual predilection for SHL.
• The right and left ears appear equally
  vulnerable.
• It affects about 4,000, usually between 40-60
  years old

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Our Role

• Test to rule out middle ear pathology and confirm
  sensorineural lesion
• Understand the emotional aspect to this type of
  hearing loss and need for counseling
• Three step approach administrative, medical,
  rehabilitative

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Clincial Example

• 46-year-old female
• Sudden onset of unilateral tinnitus and decreased
  hearing while at work
• Awoke in the morning to limited hearing in left
  ear

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• MRI indicated no structural anomalies
• Audiometry Profound loss across all frequencies
  tested
• Diagnosed as an idiopathic viral infection,
  treated with steroids
• Currently, hearing has not improved

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• Complains of inability to localize
• Habit of answering the phone with poor ear
• Discussed possibilities for ALDs for phone use
  and CROS hearing aids
• Any other suggestions?

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References

• Menner, A. (2003) A pocket guide to the ear. New
  York Thieme.
• Vause, N. (2002) Idiopathic Sudden Sensorineural
  Hearing LossOn the Other Side of the Audiometer.
  Military Audiology Short Course.
  http//www.militaryaudiology.org/masc2002/07_ISSHL
  .html. Retrieved April 15, 2008.
• Wynne, M., Diefendorf, A., Fritsch, M. (2001)
  Sudden Hearing
• Loss. The ASHA Leader Online,
• http//www.asha.org/about/publications/leader-onli
  ne/archives/2001/. Retrieved April 20, 2008.

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Autoimmune Disorders

• Molly Simpson and Beth Burlage

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Autoimmune disorder

• An autoimmune disorder is a condition that
  occurs when the immune system mistakenly attacks
  and destroys healthy body tissue Medline Plus
• Women are more commonly affected than men
• Autoimmune disorders can cause
• Destruction of different body tissues
• Changes in organ function
• Abnormal growth of an organ

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Autoimmune Inner Ear Disease (AIED)

• Syndrome with progressive, fluctuating bilateral
  sensorineural hearing loss, dizziness and
  sometimes tinnitus which progresses over weeks to
  months
• First proposed in 1979
• Can be confused with Menieres Disease
• Responsible for a very small number of hearing
  impairment cases (lt 1)
• Most common in middle-aged women

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Causes of AIED

• Caused by antibodies or immune cells that damage
  the inner ear
• Bystander damage inner ear damage causes
  cytokines to be released which create further
  immune reactions after a delay (fluctuating
  symptoms)
• Cross- reactions antibodies or T-cells
  accidentally damage the inner ear if the ear
  shares common antigens with a harmful substance
  the body is already trying to fight off (COCH5B2)
• Intolerance the body may not know all of the
  antigens in the inner ear. When they are
  released (after surgery, trauma or infection),
  the body attacks them (partially immune
  privileged locus)
• Genetics some people are genetically
  pre-disposed to immune disorders
• This is the currently favored theory

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Diagnosis of AIED

• Audiological Evaluation
• Vestibular Testing
• ABR (to rule out AN)
• ECochG (to rule out Menieres)
• Responsiveness to steroids
• Blood tests for general autoimmune disorders
• Blood tests for inner ear disorders
• Anti-cochlear antibodies (HSP70)
• Lymphocyte transformation assay
• Blood tests for diseases/problems that mimic AIED
• FTA (syphilis infection)
• Lyme disease
• Diabetes

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Treatment of AIED

• Corticosteroids (managed by a Rheumatologist)
• Prolonged usage is shown to have serious negative
  side effects Broughton, Meyerhoff and Cohen, 2004
• Dosage is often tapered to the lowest one that
  prevents fluctuations in hearing Broughton et.al
• Benefit is not found in all patients and high
  dosages may be needed occasionally as a booster

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Treatment continued

• Cytotoxic Agents (chemotherapy-type medications)
• Methotrexate
• Highly toxic and studies show limited benefit
• Cochlear Implants
• For individuals who do not respond to medical
  treatment and profound hearing loss is permanent

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Take home message

• AIED is one of the few reversible causes of
  sensorineural hearing loss Gopen, Keithley and
  Harris, 2006
• Early diagnosis and treatment are crucial to
  reversal or progression!

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References

• Mathews, J., Kumar, B.N. (2003), Autoimmune
  sensorineural hearing loss, Clinical
  Otolaryngology, 28479-488.
• Broughton, S.S., Meyerhoff, W.E., Cohen, S.B.
  (2004), Immune-mediated inner ear disease
  10-year experience, Seminars in Arthritis and
  Rheumatism, 34544-548
• Gopen, Q., Keithley, E.M., Harris, J.P. (2006),
  Mechanisms underlying autoimmune inner ear
  disease, Drug Discovery Today Disease
  Mechanisms, 3(1)137-142.
• Vestibular Disorders Association
• http//www.vestibular.org/vestibular-disorders/spe
  cific-disorders/autoimmunity.php
• American Hearing Research Foundation
• http//www.american-hearing.org/disorders/autoimmu
  ne/autoimmune.html

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