Flashcards in Lecture 10- Inner Ear Diseases Deck (31)
What is the definition of sudden SNHL?
> 30 dB decrease at 3 consecutive frequencies
Rapid onset: 72 hours or less
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
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?
Partial to complete
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
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?
Cochlear Meniere disease
Chronic progressive deafness of adolescence
Recessive hereditary deafness
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
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
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
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
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 Lymphocytic choriomeningitis virus
Congenital and Acquired
o HIV and HSC
o Varicella Zoster Virus
o West Nile Virus
o Zika Virus
What types of hearing loss can result from viruses?
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?
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
What is the presentation of conductive hearing loss related to HIV?
o Recurrent OM
o Otitis externa
o Acquired aural atresia
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