Ear Flashcards
Draw the structure of the ear?
Describe how a sound is heard.
Find picture on google
- Sound waves directed into ear canal by pinna
- Sound wave hits eardrum and vibrates it
- The eardrum attaches to malleus, which attaches to incus, which attaches to stapes. There is chain reaction of vibration through the bones
- The stapes is connected to the cochlea, it has a piston effect which passes on the vibration to the fluid in the cochlea
- The fluid vibrating sends a signal to the brain via nerve VIII
- Signal is processed by the brain
What are the bones of the ear? Which order are they in?
From outside going in:
Malleus
Incus
Stapes
Where are the cut offs between outer, middle and inner ear?
Outer: up to eardrum
Middle: inside of eardrum up to cochlea
Inner: the rest!
What is the eustachean tube?
What is its purpose?
Tube that goes from the middle ear to nasopharynx
Equalises pressure of middle ear to that of external auditory meatus
How do we balance?
The semi-circular canals
They are attached to the cochlea
They contain endolymph. Upon movement of the head the flow changes speed or direction.
Sensory receptors send signals to the brain
Which nerves pass through the inner ear?
VIII - vestibulocochlear, which innervates cochlea and vestibular apparatus
VII - facial, does not innervate anything in inner ear
Draw and label the structures of the pinna?
http://teachmeanatomy.info/head/organs/ear/external-ear/
What are some causes of a painful ear?
50% is referred pain from jaw, throat, teeth
Other causes: Otitis externa Otitis media Furunculosis Temporomandibular joint dysfunction
What is otitis externa?
Pathophysiology
Inflammation of the external ear (external auditory meatus, auditory canal, outer surface of eardrum)
Caused by infection
Causes of otitis externa?
Infection: S aureus, P aeruginosa, H zoster
Skin condition: acne, psoriasis, eczema
Irritants: swimming pool water, trauma (foreign body)
Presentation of otitis externa?
Erythema, oedema in ear canal
Exudate
Pain moving tragus or auricle
Pre-auricular lymphadenopathy
Hearing loss
Fever
What is the other name for swimmer’s ear?
Acute diffuse otitis externa
What is a furuncle?
A small localised infection arising from a hair follicle in the canal
S. aureus
Very painful
What is a serious complication of otitis externa?
Necrotising (malignant) otitis externa
Extension of infection into the mastoid and temporal bones
Necrotising (malignant) otitis externa.
Pathophysiology
Presentation
Causative bugs
Risk factors
Extension of infection from otitis externa into the mastoid and temporal bones resulting in osteomyelitis
S. aureus
P. aeruginosa
Pain
Oedema
Exudate
Facial nerve palsy
Diabetes, immunocompromise
Investigations of otitis externa?
Look for exudate in canal
Look for perforated tympanic membrane
Swab
If you can’t see the eardrum how can you tell if its perforated?
They can taste medication placed in ear
They can bow air out of ear when nose pinched
Management of acute otitis externa?
Topical drops: antibiotic + steroid
Can use wicks
Remove debris
If cellultitis or lymphadenopathy treat with oral abx
If systemically unwell need an ENT review and possible IV abx
In chronic otitis externa, what things could be perpetuating the problem?
Scratching ear
Swimming
Poor compliance with treatment
Skin disease
What do the topical drops used to treat otitis externa contain?
Antibiotic: gentamicin, ciprofloxacin
Steroid: dexamethasone or hydrocortisone
What are some causes of discharging ear?
Otitis media
Otitis externa
Glue ear
Cholesteatoma
What is otitis media?
Types?
Inflammation / infection of the middle ear
Types:
- AOM: acute otitis media
- OME: otitis media with effusion (glue ear)
- COM: chronic otitis media
Risk factors for acute otitis media?
Younger age: because eustachian tube is at a less acute angle so material is transmitted through it to middle ear easier
Contact with infections (nursery, daycare, school)
Craniofacial abnormalities
Smoking in household
Dummy use
Clinical features of acute otitis media?
What would you see OE?
Pain, pulling at ear Maliase Irritability crying Fever Coryza Vomiting
Tympanic membrane appears:
Red, yellow or cloudy
Bulging
Air-fluid level
After perforation:
Pain is much less
Discharge in auditory canal
Investigations of acute otitis media?
No investigation needed
Can do culture of ear discharge
Audiometry if there’s chronic hearing loss
CT or MRI if concerned about complications
Management of acute otitis media?
Consider admission if:
- systemic unwell
- very young
- suspected acute complications
Treat symptoms: paracetamol, NSAIDs
No antibiotics unless systemically unwell
What bugs cause otitis media?
H influenzae
S pnuemoniae
M catarrhalis
S pyogenes
Complications of acute otitis media?
Progression to chronic suppurative otitis media
Labyrinthitis Meningitis Intracranial sepsis Facial palsy Abscess Sepsis
What is chronic suppurative otitis media?
Pathophysiology
Chronic inflammation of middle ear
Ongoing cycle of inflammation, ulceration, infection, granulation of middle ear
Which over time damages nearby structures
Risk factors for chronic suppurative otitis media?
Multiple episodes of acute otitis media
Lots of contact with infections: Living in crowded conditions, nursery, daycare
Craniofacial abnormalities
Clinical features of chronic suppurative otitis media?
Chronically discharging ear (otorrhoea)
Conductive hearing loss in affected ear
No signs of acute infection
Otoscope:
- granulation tissue in middle ear space
- discharge clear, serous
Chronic suppurative otitis media can be safe or unsafe. What does this mean?
Safe: CSOM without cholesteatoma
Unsafe: CSOM with cholesteatoma
Investigations of chronic suppurative otitis media?
Don’t bother with swab
Audiology would show conductive hearing loss
CT or MRI could show cholesteatoma, malignancy, bone involvement
Management of chronic suppurative otitis media?
ENT referral: who can remove discharge and fully view the tympanic membrane
Topical antibiotics (but not gentamicin or hydrocortisone)
Surgical: repair TM, treat the cholesteatoma
In patients with otitis media, what should you not prescribe?
Topical ear drops containing
- aminoglycosides (gentamicin)
- hydrocortisone
Because they’re ototoxic, and if the tympanic membrane is perforated the drops will get into middle + inner ear
Complications of chronic suppurative otitis media?
Infection spreading to bone
Labyrinthitis
Facial paralysis
Meningitis, intracranial abscess
Hearing loss
Tympanosclerosis
What is the proper name for earwax?
What does it contain?
Cerumen
Contains sebum, dead cells, sweat, hair, dust
How would you manage impacted cerumen?
Ear drops: sodium bicarbonate, olive oil
Irrigation
Microsuction
Clinical features of impacted cerumen?
Hearing loss Blocked ears Tinnitus Itchiness Discomfort
What are some contra-indications for ear irrigation?
Current infection
Perforated TM
Grommets
Otitis media in last 6 weeks
Cleft palate
What is ear irrigation?
Using water to flush out ear wax
What is cholesteatoma?
A growth of keratinising squamous epithelium in the middle ear
It is not cancer but it grows independently so is locally invasive
Can erode the ossicles (ear bones), nerves, and sometimes even through base of skull
How is cholesteatoma classified? What’s the cause of each?
Congenital: occurs during embryogenesis
Primary acquired: eustachian tube defect causing negative middle ear pressure
Secondary acquired: insult to TM, squamous epithelium gets into middle ear and grows there
Presentation of cholesteatoma?
Progressive conductive hearing loss
Otorrhoea
Signs of infection
As lesion grows and erodes surrounding structures
- pain
- vertigo (erosion into inner ear)
- tinnitus
- headaches
- facial nerve palsy
How does the cholesteatoma erode into bones?
It produces osteolytic enzymes which can erode bone
Investigations of cholesteatoma?
Otoscopy: can see keratinising lesion, discharge
CT: show extent of lesion and look for bony defects
Management of cholesteatoma?
Surgical: remove the cholesteatoma
Can manage conservatively if the patient is unfit for surgery, but it will grow and erode things
What are the complications of cholesteatoma?
Progressive conductive hearing loss
Facial nerve palsy
Infections leading to abscesses
Intracranial complications
What types of discharge do these conditions point to?
- Otitis externa
- Acute otitis media
- Chronic otitis media
- Cholesteatoma
Externa: scanty discharge, blood, liquid wax (not mucous)
Acute Otitis media: mucous discharge
Chronic otitis media: Serosanguinous
Cholesteatoma: offensive
Pathophysiology of acute otitis media?
Infective organisms reach middle ear from nasopharynx via eustachian tube
Often follows a URTI
What is glue ear?
What causes it?
Another name for otitis media with effusion
Collection of fluid in middle ear cleft
Chronic (not acute) inflammation
Follows acute otitis media
Or eustachian tube defect (blocked, so reduced aeration of middle ear)
Clinical features of glue ear?
OE?
Hearing loss
- poor listening
- poor speech
- inattention
- poor progress at school
Often no pain so hard to pick up
Otoscopy: retracted or bulging drum, dull, grey, yellow
Investigations of otitis media with effusion?
AKA glue ear
Otoscopy
Audiology
Tympanometry: checks mobility of TM
Management of otitis media with effusion?
Observation
Autoinflation: of the eustachian tube via the nose
Grommets (aka tympanostomy)
Antibiotics, steroids etc are not recommended
What is tympanostomy?
Grommets
Tiny tubes that go through the TM to ventilate the middle ear
Describe audiometry?
In a soundproof room
Headphones play sounds at different frequencies
Patient signals / presses button when they hear it
Documents lowest and highest freq sounds they can hear
Also done with bone conduction
What is tympanogram?
Assess tympanic membranes and bones mobility by changing air pressure in ear canal
