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Nervous System: Unit III > Otology > Flashcards

Flashcards in Otology Deck (14):
1

Common causes of conductive hearing loss

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

2

Common causes of sensory hearing loss

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

3

Characteristics of prebycusis

  • 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

4

Characteristics of hair cell loss due to noise exposure

  • 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

5

Signs/Sx of Meniere's Disease/Endolymphatic hydrops

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

6

Possible etiologies of Endolymphatic hydrops

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

7

Time course of endolymphatic hydrops

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

8

Criteria for dx of endolymphatic hydrops

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

9

Causes of neural hearing loss

  • 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

10

Audiogram: conductive vs. sensorineural hearing loss

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

11

Characteristics of hearing loss due to ototoxicity

  • 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

12

Most common cause of non-syndromic hearing loss

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

13

Characteristics of hearing loss due to disruption of endocochleaur potential

  • 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

14

Possible etiologies of disordered inner ear fuild homeostatis

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