Hearing Loss Flashcards
What is conductive deafness?
Pathologies of the outer and middle ear
What is sensorineural deafness?
Pathologies of the inner ear
How would a Pinna deformity affect hearing?
May reduce volume of sound entering external acoustic meatus by 5-10dB
What is canal atresia?
Congenital disorder → absent or closed external acoustic meatus
What is a cerumen plug?
Wax - may obstruct meatus, or sit against drum, dampening vibrations
Wax is only produced in the outer 1/3 of EAM - usually pushed in by cotton buds etc.
What is otitis externa? and what are the causes?
Infection of the soft tissues surrounding the EAM
Usually caused by gram -ve bacteria - occasionally fungal
Pseudomonas may → malignant otitis externa → invasion (CN palsies, intracranial)
What is the presenation of otitis externa?
Pain - pinna my be tender on movement
Erythema - may be diffuse or localised if OE boil (furuncle)
- Furuncles always in outer EAM as no follicles deeper
May spread to form pre-auricular rash (erysipelas) or cellulitis
What is the treatment for otitis externa?
Acute bacterial - Topical ABx - Gentamycin, Neomycin - drops/Pope Wick
Acute viral - Topical antifungals - Clotrimazole, Nystatin
- Swelling reduction - Magnesium sulphate
- Chronic OE → swabs, clean, antimicrobials + steroid
What is osteotoma?
Surfer’s ear - benign growth of bone surrounding EAM → stenosis/obstruction
Stimulated by cold water
What is acute otitis media?
Inflammation of the middle ear - can be supparative (pus discharge) or secretory (mucoid secretions)
The whole middle ear including the mastoid antrum and eustatian tube.
What causes acute otitis media?
Usually capsulated gram +ves -
Strep P,
Haem Inf,
Moraxella Cartharralis
What are the symptoms of acute otitis media?
Discomfort → Deep pain (also over mastoid process)
Impaired hearing
Fever, malaise
What are the signs of acute otitis media?
Inflamed tympanic membrane pre-perforation
Perforation and profuse mucoid discharge post perforation
What is the treatment for acute otitis media?
Oral ABx - Amoxicillin or Co-Amoxiclav; also Trimethoprim
Analgesia
Warm olive oil drops
What are some complications of acute otitis media?
Mastoiditis - infection → mastoid air cells → erosion of bony trabeculae. CT to check +/- surgical exploration
Facial palsy, Venous sinus thrombosis, Meningitis, Brain abscess
What is chronic mucosal otitis media?
Persistent/recurrent infection and perforation - sequalae of AOM
What can cause Chronic Squamous otitis media?
Cholesteatoma
What are the two types of glue ear?
Can be:
Supparative - pus secretion
Secretory - mucoid secretions
What is the pathophysiology of glue ear?
Inefficient drainage of the middle ear via eustatian tube → mucoid build up
Partial resorption of mucous → decrease pressure → drum retraction
Often bilateral
In what children is glue ear common?
Down’s Syndrome children, due to horizontal tubes
Also associated with adenoid infection - blocks exit
What is a possible cause of Glue ear in adults?
Nasopharyngeal Carcinoma
What are the symptoms and signs of glue ear?
Conductive hearing loss - may lead to behaviour problems/developmental delay
Recurrent infection +/- perforation
Retracted tympanic membrane
What is the treatment for glue ear?
Conservative - treat if two +ve tympanograms >3 months apart
Grommets - tube inserted through drum → equalise pressure, allow drainage
Adenoidectomy
Hearing aid
What investigations should be done for glue ear?
Tympanometry - measures membrane compliance
Noise sent down EAM, reflection from ear drum recorded
Pathology → ↓Compliance
What is a “safe” perforation? and how would you treat it?
Central perforation - rim of pars tensa all the way round perforation
Treat cause
Conservative - membrane should grow back
Surgery - Myringo/Tympanoplasty - necessary if umbo damaged, as source of epithelial growth
What is an “unsafe” perforation?
Marginal perforation/Attic perforation
Any perforation involving margin of membrane or pars flaccida may → cholesteatoma growth +/- necrosis of underlying bone
How would you treat an “unsafe” perforation?
Combined approach tympanoplasty - graft close perforation but may enclose cholesteatoma
Mastoidectomy - middle ear and drum destroyed - mastoid cavity and middle ear joined, and skin encouraged to grow along walls
What is a cholesteatoma?
Sac of epithelium grows into middle ear
Due to sucking of pars flaccida into middle ear
or
Downwards migration of epithelium from attic/marginal perforation
What are complications of cholesteatoma?
Erode ossicles, inner ear, facial nerve or meninges (→ meningitis, abscess)
How would cholesteatoma present?
Discharge and foul odour - infection of dead tissue at core
Conductive hearing loss - ossicle erosion, or progress into inner ear
Facial nerve palsy, mastoiditis, meningitis, brain abscess
Examination might show visible cholesteatoma
What is the treatment of cholesteatoma?
Mastoidectomy - removal of middle ear and drum, mastoid cavity and middle ear joined and skin encouraged to grow along walls
In early presentation, CA Tympanoplasty is possible.
What is otosclerosis?
Growth of small focus of bone - obstructing stapes vibration → oval window
Inherited, autosomal dominant
What is the most common hearing loss cause in young/middle-ages adults?
Otosclerosis
How would someone with otosclerosis present?
Onset 30+
Progressive conductive hearing loss
Also sensorinerual loss if cochlea affected
What investigations would you do for otosclerosis?
Audiograms conductive hearing loss in typical OS pattern
Tympanograms - decreased compliance
CT
What is the treatment for otosclerosis?
Stapedectomy - replace stapes with piston attached to incus
What is ossicular discontinuity?
Infection - long process of incus eroded
Head trauma - dislocation
What is presbyacusis? what is the pathophysiology?
Progressive age-related sensorineural hearing loss.
Hair cell degeneration, especially at base of cochlea (higher frequencies)
How does presbyacusis present?
Progressive, bilateral sensorineural hearing loss
Loss of consonants
Problem drowning out background noise
What investigation should be done for suspected presbyacusis?
Audiogram - symmetrical SN hearing loss, worse at high frequencies
What is the treatment for presbyacusis?
Hearing aids (inc. cochlear implant)
What noise level is significant for acute and chronic noise induced hearing loss?
Acute >120dB
Chronic >80dB
What would the audiogram show for someone with noise induced hearing loss?
Notched audiogram - hearing loss worst at one frequency
What are possible causes for ototoxicity?
Drugs - Aminoglycosides (gentamycin), Furosemide, Platinum therapeutics
Reversible drugs - quinine, aspirin
How does ototoxicity present?
SN hearing loss
Tinnitus
Vertigo +/- nystagmus
What is acoustic neuroma?
Vestibular Schwannoma - benign tumour of myelin sheath schwann cells of vestibular nerve in internal acoustic meatus
Hearing is affected first - narrow acoustic nerve
Motor neurons thicker, so balance compensates
How might acoustic neruoma present? What investigations should be conducted and what treatments?
Progressive unilateral sensory hearing loss
Mild vertigo/imbalance but balacne centre compensates
MRI
Surgery or radiotherapy
