Contents
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
- Measles, mumps, meningitis and syphilis can damage the cochlear
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