The Middle Ear Flashcards
What does the middle ear consist of?
Ossicles - MIS bones - Malleus, Incus, Stapes
Eustachian tube
Between tympanic membrane and oval window
What is otosclerosis?
Increased boney turnover leading to sclerosis and fixation of stapes to oval window
May eventually affect bone structures of cochlea
What are some causes of otosclerosis?
Genetic - autosomal dominant
Environmental factors - hormones in pregnancy
Who does otosclerosis affect?
Females
15-35yo
Symptomatic in about 1-2% of population
How does otosclerosis present?
Progressive hearing loss (bilateral in 70%) - worse for low tones (male voices harder to determine)
Tinnitus
Improved hearing in noisy surroundings - early stage
Patients speak quietly - enhanced bone conduction so their own voice sounds loud
Family history
Normal examination but pos. schwartze sign
What is Schwartze sign?
Pink hue to tympanic membrane (vascular hyperaemia of immature bone)
How would you investigate otosclerosis?
Tympanogram - normal type A trace
Pure tone audiogram - conductive hearing loss, characteristic Carhart notch at 2kHz
CT
How is otosclerosis managed?
Conservative - hearing aid
Surgery - Stapedectomy
What does the middle ear have important close relations to?
Internal carotid artery
Internal Jugular Vein
Facial Nerve
What muscles are present in the middle ear? What is their function?
Tensor tympani - attach to handle of malleus - CNV3
Nerve to stapedius - attach to stapes - CN7
Contract in response to loud noises to inhibit vibration and reduce sound transmission
What are the types of otitis media?
Acute OM - acute inflammation of the middle ear
Acute suppurative OM - presence of pus in middle ear
Otitis media with effusion - Chronic inflammation of the middle ear with presence of glue like effusion behind tympanic membrane
Chronic suppurative OM - long standing pus in middle ear - often associated with perforated TM
What are the risk factors associated with acute otitis media?
Smoker/smoking in household Bottle fed Craniofacial abnormality - e.g. Down's Allergies Chronic Sinusitis
How does acute otitis media appear on examination?
Red, yellow or cloudy
Bulging disk
Air fluid level visible
Discharge in external acoustic meatus due to perforation
What is the pathophysiology of acute otitis media?
Organism reach middle ear from nasopharynx via the eustachian tube - flatter in children
70% bacterial - H Influenzae/S Pneumoniae
Viral - RSV or rhinovirus
How does acute otitis media present?
Pain - children tug at ear Hearing loss Fever Malaise Crying, poor feed, irritable Coryza/co-incidental bronchiolitis
How is acute otitis media managed?
Paracetamol/ibuprofen + warm compress
Delayed prescription of amoxicillin 4 days
If <3months - immediate Abx is systemically unwell or at risk of complications
What differentials are considered for acute otitis media?
Otits externa/URTI
Dental problem
Cardiac issue - referred pain from MI
Temporomandibular Joint Dysfunction
Cranial Nerve Palsy
Headaches
What complications can arise from acute otitis media?
TM perforation
Progress to chronic suppurative otitis media
Meningitis/Sepsis
Facial nerve palsy
Febrile convulsions
Mastoiditis
What is mastoiditis?
Inflammation of mastoid periosteum and air cells following spread of acute otitis media
What is glue ear?
Otitis Media with Effusion - fluid in the middle ear with chronic inflammation
How common is glue ear?
80% of children have an episode by the age of 10
When does glue ear normally occur?
Following acute OM
More likely if underlying Eustachian tube dysfunction, adenoidal hypertrophy or infection
How does glue ear present?
Hearing loss - tv volume high, poor concentration, impaired speech development
Intermittent ear pain, fullness and popping
PMG of recurrent ear infections and URTI
How would the tympanic membrane appear with glue ear?
Opacification
Loss of light reflex
Indrawn eardrum
Fluid level
How would you investigate and manage glue ear?
90% self-resolve so just require ear hygiene advice
3 months - refer to audiology - may show conductive hearing loss
Repeat hearing test after another 3 months, if still showing hearing loss then refer to ENT
When is grommets (+- adenoidectomy) considered for glue ear?
Bilateral otitis media with effusion (OME) >3 months
> 25dB loss in good ear
OME cause severe developmental problems
What surgical complications can arise from grommet insertion +- adenoidectomy?
Tympanosclerosis
Infection
Chronic perforation
What is chronic suppurative otitis media?
Chronic pussy inflammation of the middle ear and mastoid accompanied by tympanic membrane perforation +- cholesteatoma
What is the difference between safe and unsafe chronic suppurative otitis media?
Safe - central (tubotympanic perforation), no cholesteatoma
Unsafe - top (atticoantral perforation) - cholesteatoma
How does Chronic Suppurative Otitis Media present?
> 2 weeks otorrhoea
TM perforation
Conductive hearing loss
If otalgia, fever or vertigo req. URGENT assessment!
What may be seen on examination with Chronic Suppurative Otitis Media?
Discharge - serous, purulent or cheese like
Granulation tissue within external acoustic meatus/middle ear space
Middle ear mucosa oedematous and red
How is Chronic Suppurative Otitis Media managed?
Routine ENT assessment:
- micro suction to visualise TM and remove debris
- topical ahminoglycosides (ototoxic but benefit outweigh risk)
- topical steroids - reduce granulation tissue
- Surgery - if unsafe or persistent despite other treatment
What complications can occur due to chronic suppurative otitis media?
Facial nerve palsy
Meningitis
Labyrinthitis
Abscess
Long term - hearing loss & tympanosclerosis
What is a cholesteatoma?
Keratinising squamous epithelium within the middle ear following tympanic membrane retraction
Why should otitis media with effusion in adults be treated as suspicious?
Very rare
5% have head and neck cancer
What are the other risk factors for otitis media with effusion in adults?
Paranasal sinusitis - Eustachian tube inflammation and dysfunction
Severe nasal septum deviation - block airway
Large tonsils - block ET
Barotrauma
How should otitis media with effusion in adults be managed?
Urgent ENT referral
If no underlying cause - treat as in children: self resolve/grommets if persistent or >25dB hearing loss
What complications are associated with stapedectomy?
Sensorineural hearing loss Tinnitus Perforated TM Facial nerve injury Taste disturbance
