Common causes

  • External meatus blocked by wax
  • Presbyacusis

Sensorineural hearing loss

Presbyacusis

  • Loss of hair cells on cochlear as increase in age
  • Audiogram; High frequencies lost first, low frequencies stay in normal range, no increased air-bone gap
  • Usually noticed clinically after 60
  • Variability in degree of hearing loss and age of onset
  • No treatment to prevent worsening
  • Can cause significant social and work handicaps
  • Aural hearing aids used to improve hearing

Idiopathic hearing loss

  • Sudden deterioration of hearing. Ear may feel blocked
  • Tinnitus and vertigo can be present
  • Thought to be due to viral infection of vascular event
  • Rx; bed rest and vasodilators

Noise exposure

Either due to sudden or prolonged exposure
Commonly occupational exposure; should wear ear protectors if exposed to more than 90dB
Tinnitus and ‘wooly ears’ experienced after exposure
Audiogram; loss of very high frequencies first
Rx; aural hearing aids

Inflammatory diseases

Ototoxic drugs

  • Systemic aminoglycosides
  • Cytotoxic agents
  • Salicylates and quinine cause reversible damage
  • Can cause hearing loss and imbalance as can affect cochlear and/or labyrinth.

Tumours

  • Rare
  • Tumours of CNVIII
  • Causes progressive unilateral hearing loss and tinnitus
  • Investigate with MRI
  • Rx; surgical removal

Conductive hearing loss

Classified according to the anatomical location of the pathology
External auditory meatus

  • Wax; removal by cotton buds usually impacts wax and worsens obstruction.
    • Rx; soften using sodium bicarbonate TDS or hydrogen peroxide then syringe or remove by blunt hook.
  • Keratosis obturans; accumulation of desquamated skin which can erode the canal
  • Exostoses; bony growths which occlude external meatus. Common in swimmers. No treatment needed unless causing problems.

Eardrum

  • Perforation; traumatic or due to chronic otitis media.
    • Rx; either heal naturally or tympanoplasty carried out

Middle ear

  • Discontinuity of ossicles
  • Otosclerosis;
    • New bone growth in middle ear causes fusion of stapes footplate to oval window
    • Causes conductive hearing loss in young adults
    • Ear drum looks normal on examination
    • Often a family Hx
    • Pregnancy worsens symptoms
    • Rx; surgery or hearing aid

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