Hearing loss/Impaired hearing Flashcards
Tympanic membrane perforation
Hx: pain, conductive hearing loss, tinnitus
Exam: bleeding from ear, clot in meatus, visible tear in tympanic membrane
90% heal spontaneously within 6 wks;
Sx appropriate for larger perforations
2 types of hearing loss/impaired hearing
- conductive hearing loss
a. caused by lesions in external or middle ear
b. interference w mechanical reception or amplification of sound, as occurs w dz of auditory canal, tympanic membrane, or ossicles, creates conductive hearing loss - sensorineural hearing loss: due to lesions in cochlea or CN VIII (auditory branch)
Causes of Conductive hearing loss/impaired hearing
- external canal
- cerumen impaction: buildup obstructs auditory canal (most common cause)
- otitis externa
- exostoses: bony outgrowths of external auditory canal related to repetitive exposure to cold water (scuba divers, swimmers) - tympanic membrane perforation
- usually due to trauma (direct or indirect)
- may be secondary to middle ear infection - middle ear
- any cause of middle ear effusion (fluid in middle ear interferes w sound conduction): otitis media, allergic rhinitis
- otosclerosis: bony fusion (immobilization) of stapes to oval window; autosomal dominant condition (variable penetrance); corrected w sx; rarely progress to deafness
- other: neoplasms, congenital malformations of middle ear
Causes of sensorineural hearing loss
- presbycusis (most common cause)
- gradual, symmetric hearing loss assoc w aging; most common cause of diminished hearing in elderly patients
- pathology: degeneration of sensory cells and nerve fibers at base of cochlea
- hearing loss most marked at high frequenceis w slower progression to lower frequencies - noise induced hearing loss
- chronic, prolonged exposure to sound levels > 85 db
- hair cells in organ of Corti damaged - infection: viral or bacterial infection of cochlear structures or labyrinth
- drug induced hearing loss
- aminoglycoside antibiotics, furosemide, ethacrynic acid, cisplatin, quinidine
- aspirin can cause tinnitus and reversible hearing impairment - injury to inner ear or cochlear nerve (eg, skull fracture)
- Congenital (TORCH infections)
Toxoplasmosis, Syphilis/HIV, Rubella, CMV, HSV - Ménière’s disease
- fluctuating, unilateral hearing loss
- sensorineural hearing loss (usually unilateral), sense of pressure/fullness in ear, tinnitus, vertigo
- vertigo usually responds to dietary salt restriction and meclizine, but hearing loss is progressive - CNS causes
- acoustic neuromas, meningitis, auditory nerve neuritis (multiple sclerosis, syphilis), meningioma
Clinical features conductive hearing loss
decreased perception of sound esp for low frequency sounds
can hear loud noises well
Sensorineural hearing loss clinical features
difficulty hearing loud noises, shouting may exacerbate problem (annoying)
- can hear sounds, but has trouble deciphering words (poor speech discrimination)
- more difficulty w high freq sounds (doorbell, phone, child, female)
- tinnitus often present
Diagnosis of hearing loss
- whisper test: ask pt to repeat words in tested ear maskiing other ear while do it
audiogram essential
MRI in selecte cases (Cns tumor or MS suspected)
Treatment hearing loss
- cerumen impaction: treat w irrigation after many days of softening w carbamide peroxide (debrox) or triethanolamine (cerumenex)
Treatment conductive hearing loss
treat underlying cause
sx techniques (tympanoplasty, which reconstructs middle ear) for pts w chronic otitis media ; stapedectomy for otosclerosis
- hearing aids
Treatment sensorineural hearing loss
- treat underlying cause
- hearing aids
- cochlear implants: transduce sounds to electrical energy, stimulate cn 8
Clinical pearls: weber and rinne tests
- conductive hearing loss:
- abnormal rinne: bone conduction better than air conduction
- weber: sound lateralizes to affected side (tuning fork perceived more loudly in ear w conductive hearing loss) - sensorineural loss
- normal rinne test-air conduction better than bone condcution
- weber: sound lateralizes to unaffected side
