Lecture 10- Inner Ear Diseases

Question 1

What is the definition of sudden SNHL?

Answer 1

> 30 dB decrease at 3 consecutive frequencies

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

Question 2

What is the epidemiology and natural Hx of SSNHL?

Answer 2

Peak age of onset: 6th decade

M=F

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

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

Question 3

What is the etiology of SSNHL?

Answer 3

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

Question 4

What are the presenting symptoms of SSNHL?

Answer 4

Aural fullness- primary presenting Sx

Noticed on awakening

Tinnitus in 70%
 Precede or concurrent

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

Question 5

What is the prognosis of SSNHL?

Answer 5

Spontaneous recovery
 Partial to complete
 32-65%

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

Medical intervention for known causes and ISSNHL
 Timing is critical

Question 6

What are the variables affecting the prognosis of SSNHL?

Answer 6

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)

Question 7

What is an autoimmune inner ear disease?

Answer 7

Cochleovestibular system is compromised by one’s own immune system

Question 8

What are the differentials for AIED?

Answer 8

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

Question 9

What is Type I for AIED?

Answer 9

Organ (ear) specific

Presentation
 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

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

Question 10

What are the therapeutics for AIED?

Answer 10

Corticosteroids
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

Question 11

What are AIED therapeutic outcomes?

Answer 11

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

Question 12

How is autoimmune SNHL diagnosed?

Answer 12

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

PE
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

Imaging
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	ESR
o	Rheumatoid factor
o	ANA
o	Lyme titer
o	HIV testing

Question 13

What are the different viral causes of hearing loss?

Answer 13

Congenital
o CMV
o Rubella
o Lymphocytic choriomeningitis virus

Congenital and Acquired
o HIV and HSC

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

Question 14

What types of hearing loss can result from viruses?

Answer 14

Typically SNHL

Can cause CHL, mixed, retrocochlear

Question 15

What are the mechanisms of injury in viral hearing loss?

Answer 15

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

Question 16

What are treatment and prevention options for viral hearing loss?

Answer 16

• Vaccines
• Antivirals
• Amplification

Question 17

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

Answer 17

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

Question 18

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

Answer 18

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

Question 19

What is the presentation of SNHL related to HIV?

Answer 19

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

Question 20

What is acquired measles?

Answer 20

• Rubeola virus

* Route of transmission: respiratory secretions

Question 21

How is acquired measles diagnosed?

Answer 21

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

Question 22

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

Answer 22

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

Question 23

What is the relationship between acquired measles and otosclerosis?

Answer 23

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

Question 24

What is acquired mumps?

Answer 24

• Paramyxovirus family

* Route of transmission: respiratory secretions

Question 25

How is acquired mumps diagnosed?

Answer 25

Based on clinical presentation/salivary anti-IgM testing

o Flu-like symptoms followed by bilateral parotiditis

Question 26

What is the hearing loss associated with acquired mumps?

Answer 26

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

Question 27

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

Answer 27

o Strophy of HC and SV

o Damage to myelin sheath around CN8

Question 28

What is the risk of HL associated with acquired mumps?

Answer 28

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

Question 29

How does labyrinthitis affect the auditory and vestibular systems?

Answer 29

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

Question 30

What is the acute phase of labyrinthitis?

Answer 30

Severe SNHL and vertigo

Question 31

What is the prognosis of auditory and vestibular symptoms associated with labyrinthitis?

Answer 31

• Hearing loss is permanent

* Vertigo slowly resolves over weeks to months