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13.03.05 Hearing loss

Causes of sensorineural hearing loss
  • MS
  • Acoustic neuroma
  • Ménière's
  • Ototoxins
    • Streptomycin
    • Gentamycin
    • Salicylates
    • Thalidomide
    • Cis-platin
    • Vincristine
  • Infection
    • Meningitis
    • Mumps
    • Measles
    • Flu
    • Herpes
    • Syphilis
  • Metastatic cancer (brain)
  • Cochlear vascular disease
  • Presbycusis


Ménière's

  • Triad
    • Recurrent vertigo
    • Fluctuating sensorineural hearing loss (Low frequency loss initially, develops to full-range)
    • Tinnitus
  • Sensation of aural fullness
  • Usually unilateral but may extend to both ears in 25-75%
  • Genetic component


Weird/wonderful diseases causing hearing loss

  • Osteogenesis imperfecta
    • Blue sclera (very thin sclera, can see blood)
  • Waardenburg syndrome
    • Heterochromia
    • Wide-set eyes
    • Low hairlines
    • Monobrow
  • Usher syndrome
    • Visual as well as hearing loss (leading cause of deaf-blindness)
  • Pendred syndrome
    • Goitre / hypothyroidism
  • Alport syndrome
    • Type IV collagen deficiency => Poor basement membrane
    • Glomerulonephritis
    • Endstage kidney disease
  • Cogan syndrome
    • Recurrent corneal inflammation
    • Fever, fatigue, weight loss, dizziness
  • Behçet's disease
    • Mucous membrane ulceration and ocular problems


Patterns of hearing loss

  • Barotrauma => Mid-range
  • Presycusis => High-end
  • Otosclerosis => Low-end
  • Meniere's => Low-end then full-range
  • Acoustic neuroma => High-end (these fibres are on the outside of the nerve => hit first)


Auditory brainstem response

  • Recorded via electrodes placed on the scalp
  • Newborn hearing screening, auditory threshold estimation, intraoperative monitoring, determining hearing loss type and degree, auditory nerve and brainstem lesion detection


Otosclerosis
  • Bilateral
  • Progressive
  • Low-frequency dip
  • Stapidectomy + metal replacement


Blood supply of the ear



Notes
  • Facial nerve runs through the ear
    • cf Taste to anterior 2/3
  • Cochlear implant indications
    • Children
    • Bilateral deafness
    • Loss of another sense
  • Wax is skin
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