Otology

Question 1

Common causes of conductive hearing loss

Answer 1

• otitis media
• TM perforation
• Cholesteatoma
• Otosclerosis
• Congenital aural atresia

Question 2

Common causes of sensory hearing loss

Answer 2

• **hair cell loss:
• presbycusis
• noise trauma
• ototoxicity
• genetic factors

Question 3

Characteristics of prebycusis

Answer 3

• Gradual, progressive bilateral hearing loss caused by degenerative physiologic changes associated with aging.
• Decreased hearing threshold sensitivity
• Decreased ability to understand supra-threshold speech
• Central auditory process impairment

Question 4

Characteristics of hair cell loss due to noise exposure

Answer 4

• Acute exposure: noise trauma
• Chronic exposure: industrial, recreational
• Phenomenon of temporary threshold shift
• OSHA regs 80 db/8hrs, 85 db/6hrs, 90 db/4 hrs

Question 5

Signs/Sx of Meniere’s Disease/Endolymphatic hydrops

Answer 5

• due to a swelling of the endolymphatic space
• Causes dizziness, hearing loss, tinnitus, fullness
• Very rarely bilateral

Question 6

Possible etiologies of Endolymphatic hydrops

Answer 6

• Autoimmune
• allergic
• blocked drainage
• excess endolymph
• viral infection
• autonomic imbalance
• nutritional deficiency
• vascular irregularities

Question 7

Time course of endolymphatic hydrops

Answer 7

• Chronic disease with active phases and remissions
• time course is unpredictable
• Eventually reach burnout which is flat hearing loss. Vertigo stops at this point.

Question 8

Criteria for dx of endolymphatic hydrops

Answer 8

• Definitive vertigo lasting 20 minutes or longer (>1 episode),
• Hearing loss
• Tinnitus
• Aural fullness

Question 9

Causes of neural hearing loss

Answer 9

• 8th nerve tumors
• MS
• Neural sarcoid, etc.
• Auditory neuropathy - all tests show normal cochlea, but transmission from cochlea to brain not working. Often idiopathic unknown

Question 10

Audiogram: conductive vs. sensorineural hearing loss

Answer 10

• Conductive
  
  • impacts all frequencies
  • bone conduction shows consistently better hearing vs. air
• Sensorineural
  
  • affects only higher frequencies
  • air and bone conduction are similar

Question 11

Characteristics of hearing loss due to ototoxicity

Answer 11

• ototoxicity ==> damage to hair cells ==> sensory hearing loss
• many drugs = ototoxic agents
• prevent ototoxicity by:
  
  • use potentially ototoxic agents only when necessary
  • monitoring hearing/vestibular fxn
• tx: stopping agents + starting corticosteroids

Question 12

Most common cause of non-syndromic hearing loss

Answer 12

• mutation @ connexion 26
• 10-20% of all genetic hearing loss

Question 13

Characteristics of hearing loss due to disruption of endocochleaur potential

Answer 13

• stria vascularis ==> maintains proper endolymph fluid homeostasis
• disordered inner ear homeostasis due to impaired blood flow, immune system dysfxn, etc. ==> dysfxn of stria vascularis
• ==> loss of endocochlear potential ==> dysfxnl sensory transduction

Question 14

Possible etiologies of disordered inner ear fuild homeostatis

Answer 14

• vascular dysfxn/vasculitis
• systemic metabolic disorders
  
  • Diabetes
  • Hypothyroidism
  • Renal failure
  • Arteriosclerosis
• Immune system-related
  
  • Lupus
  • Wegeners
  • autoimmune inner ear disease