1- Ears (Sensinoural hearing loss) Flashcards
sensorineural hearing loss
Occurs due to dysfunction of the inner ear:
- Cochlea
- Vestibulocochlear nerve.
Causes of sensorineural hearing loss include
- increasing age (presbycusis)
- excessive noise exposure
- genetic mutations
- viral infections (e.g. cytomegalovirus)
- ototoxic agents (e.g. gentamicin).
Conductive hearing loss
occurs when sounds cannot transmit due to problems with the outer and middle ear.
Sensorineural hearing loss
- Sudden sensorineural hearing loss (over less than 72 hours)
- Presbycusis (age-related)
- Noise exposure
- Meniere’s disease
- Labyrinthitis
- Acoustic neuroma
- Neurological conditions e.g. stroke, MS, brain tumours
- Medications
medications which causes sensorineural hearing loss
- Loop diuretics e.g. furosemide
- Aminoglycoside antibiotics e.g. gentamicin
- Chemotherapy drugs e.g. cisplatin
Sudden sensorineural hearing loss (<72h)
Background
- Sudden sensorineural hearing loss is defined as hearing loss over less than 72 hours, unexplained by other causes
- Otological emergency and requires immediate referral to on call ENT team
- Diagnosis made when: no conductive cause can be found
- Usually unilateral
Sudden sensorineural hearing loss (<72h) Causes/risk factors
Most cases (90%) of SSNHL are idiopathic, meaning no specific cause is found.
Other causes of SSNHL include:
- Infection (e.g., meningitis, HIV and mumps)
- Meniere’s disease
- Ototoxic medications
- Multiple sclerosis
- Migraine
- Stroke
- Acoustic neuroma
- Cogan’s syndrome (a rare autoimmune condition causing inflammation of the eyes and inner ear)
Investigations for Sudden sensorineural hearing loss (<72h)
- Audiometry -> SSNHL requires a loss of at least 30 decibels in three consecutive frequencies on audiogram
- MRI or CT head to rule out stroke or acoustic neuroma
Sudden sensorineural hearing loss (<72h) management
- Immediate referral within 24 hours of symptoms if sudden sensorineural hearing loss presenting within 30 days
- Treat underlying cause e.g. antibiotics for infection
- Idiopathic cause: oral or intra-tympanic (injected) steroids
Sudden sensorineural hearing loss (<72h) prognosis - May be permanent or resolve over days to week
Age related hearing loss- presbycusis
Background
- Age-related hearing loss (presbycusis) is the loss of hearing that gradually occurs in most of us as we grow older
- Sensorineural
- Affects high pitched sounds first
- Gradual and symmetrical
Age related hearing loss- presbycusis RF
- Age
- Male
- Family history
- Loud noise exposure- key
- DM
- HTN
- Ototoxic medication
- Smoking
causes of presbycusis
Complex- several mechanisms proposed
Changes in anatomical structures of the ear e.g.
- Inner ear
- Middle ear
- Vestibular cochlear nerve
- Loud noise
- Loss of hair cells
- Aging
- Ototoxic drugs
Presentation of presbycusis
- Bilateral hearing loss
- Gradual change and insidious
- High-pitched noises hardest to hear e.g. speech (male voices easier)
- Speech sounds slurred
- Some sounds overly loud
- Tinnitus associated
Investigations for presbycusis
- Otoscope
- Audiometry
Management of presbycusis
- Hearing aids
- Cochlear implants if hearing aids not sufficient
- Assistive devices e.g. telephone amplifier
Noise related hearing loss
Background
- Permanent hearing loss caused by being around loud noises over a long time or a very loud noise e.g. explosion
- Sensorineural
Prognosis/complications of labrynthitis
- Rarely have lasting symptoms
- If bacterial labyrinthitis more likely to have lasting symptoms
