Lecture 10- Inner Ear Diseases Flashcards Preview

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What is the definition of sudden SNHL?

> 30 dB decrease at 3 consecutive frequencies

Rapid onset: 72 hours or less
o Instantaneous
o Rapidly progressive


What is the epidemiology and natural Hx of SSNHL?

Peak age of onset: 6th decade


Unilateral >bilateral (2%)
 When bilateral, it can occur simultaneously or years/months apart

 5-20/100,000 population
 4,000 new cases per year in USA


What is the etiology of SSNHL?

Idiopathic- up to 85-90% of SSNHL
 Idiopathic: no known or defined cause

Identified at initial presentation: 10-15%

Long term follow-up: 30%

Treatment decisions made without knowing cause- need common approach


What are the presenting symptoms of SSNHL?

Aural fullness- primary presenting Sx

Noticed on awakening

Tinnitus in 70%
 Precede or concurrent

Dizziness in 40-50%
 Vertigo, imbalance, unsteadiness
 Precede, accompanying, following


What is the prognosis of SSNHL?

Spontaneous recovery
 Partial to complete
 32-65%

 Most recovery starts within 2 weeks
 90% of all improvement within 4 weeks

Medical intervention for known causes and ISSNHL
 Timing is critical


What are the variables affecting the prognosis of SSNHL?

Severity of loss
 Greater degree of loss
 Reduced word recognition

Spontaneous recovery
 Better prognosis if recover 50% hearing first 2-weeks

Association with vertigo at onset (worst chance of recovery)

Age>40 years (worst chance of recovery)


What is an autoimmune inner ear disease?

Cochleovestibular system is compromised by one’s own immune system


What are the differentials for AIED?

 Sudden deafness
 Cochlear Meniere disease
 Chronic progressive deafness of adolescence
 Presenile presbycusis
 Recessive hereditary deafness
 Luetic labyrinthitis


What is Type I for AIED?

Organ (ear) specific

 Rapidly progressive bilateral SNHL
• Pure-tone decline of 10-15 dB or >12% drop in WRS in 3-month period
 15% with vestibular symptoms
 Most have aural fullness & tinnitus
 No clinical evidence of other autoimmune disease
 Negative serology for ANA, ESR, RF

 “Rare”
 M=F
 All ages, mid-50s most common
 More common in white (non-Hispanic) population


What are the therapeutics for AIED?

o Trial of oral prednisone x30 days and retest hearing
o If hearing improves:
 Taper off steroids
 Monthly hearing assessment
 When dose reaches 10 mg/day, continue at this level x3 months before D/c
o If hearing declines during, continue at current dose for another month or increase dose back up until HL stabilizes
o Total treatment time: 6-12 minutes


What are AIED therapeutic outcomes?

Successful taper off corticosteroids and no their hearing problems

Successful taper with relapse or gradual, progressive HL over years

Steroid dependent
o Hearing stable while on steroids
o Declines when dose gets too low
o May benefit from other immumodulatory drugs
 TNF-  inhibitor- examples include etanercept, infliximab

Steroid resistant
o Il-1 receptor antagonist – anakinra (recent promise)

Although rare, AIED is one of few examples of potentially reversible SNHL. Important to diagnose and treat, and pursue new treatments


How is autoimmune SNHL diagnosed?

o Complaint of hearing loss
o Onset/progression important in differential

o Normal otoscopic exam- ASHNL
o Abnormal in some systemic immune disease

Audiologic and vestibular w/u
o SNHL: many degrees, may fluctuate
o CHL, MHL in some systemic immune diseases
o ABR to R/o 8th nerve lesion
o VNG to assess vestibular function

o MRI with and without gadolinium, attention to IAC

Serologic testing
o Western blot
 Looking for cochlear antibody
 More likely to be abnormal in active disease
o FTA-abs to rule out syphilis
o Rheumatoid factor
o Lyme titer
o HIV testing


What are the different viral causes of hearing loss?

o Rubella
o Lymphocytic choriomeningitis virus

Congenital and Acquired
o HIV and HSC

o Measles
o Varicella Zoster Virus
o Mumps
o West Nile Virus
o Zika Virus


What types of hearing loss can result from viruses?

Typically SNHL

Can cause CHL, mixed, retrocochlear


What are the mechanisms of injury in viral hearing loss?

• Direct viral damage to inner ear
• Immune system mediated damage
• Immunocompromise leading to 2o infections


What are treatment and prevention options for viral hearing loss?

• Vaccines
• Antivirals
• Amplification


What is the auditory presentation of hearing loss related to HIV?

o Prevalence: 14-49% have auditory symptoms
o Unilateral or bilateral
o CHL, MHL, or SNHL (Sensorineural in 2/3 children with HL (Uganda))
o Progressive or sudden
o Tinnitus


What is the presentation of conductive hearing loss related to HIV?

o Recurrent OM
o Otitis externa
o Acquired aural atresia
o Cholesteatoma
o Malignancy


What is the presentation of SNHL related to HIV?

o Direct damage to the auditory system
o Opportunistic infections
o Treatment with potentially ototoxic medications
o Typically mild to moderate, predominantly HF


What is acquired measles?

• Rubeola virus
• Route of transmission: respiratory secretions


How is acquired measles diagnosed?

o Fever, cough, nasal congestion, conjunctivitis
o Erythematous maculopapular rash
o Pathognomonic Koplik spots on the buccal mucosa


What is the hearing loss and vestibular function associated with acquired measles?

o Prior to vaccination: 4-9% of severe to profound childhood HL
o Sudden onset at time of rash
o Bilateral, moderate to profound, permanent SNHL
o Otitis media incidence: 8.5-25%
o 70% reduced caloric responses in one or both ears


What is the relationship between acquired measles and otosclerosis?

o Measles antigens within otosclerotic lesions
o Histology of stapes footplate- suggestive of measles infection
o Rates of otosclerosis higher in those without vaccination


What is acquired mumps?

• Paramyxovirus family
• Route of transmission: respiratory secretions


How is acquired mumps diagnosed?

Based on clinical presentation/salivary anti-IgM testing
o Flu-like symptoms followed by bilateral parotiditis


What is the hearing loss associated with acquired mumps?

o 4-5 days after onset of symptoms
o Unilateral in 80%
o Most often reversible, but can be permanent
o Reversible vestibular dysfunction- reduced/absent caloric response


What is the proposed mechanism of SNHL associated with acquired mumps?

o Strophy of HC and SV
o Damage to myelin sheath around CN8


What is the risk of HL associated with acquired mumps?

o Not correlated with severity of infection or presence of parotiditis
o Can have asymptomatic mumps associated with HL


How does labyrinthitis affect the auditory and vestibular systems?

Bacteria and fungi damage to peripheral auditory and vestibular systems through:
o Suppurative labyrinthitis
o Toxic labyrinthine damage via round window or modiolus
o Purulent exudate or infectious agent
 Enveloping CN VIII
 Via cochlea aqueduct from infected CSF


What is the acute phase of labyrinthitis?

Severe SNHL and vertigo