Ear diseases Flashcards
What is the embryological origin of the external ear?
From the 1st and 2nd pharangeal arches
Which create 6 hillocks of His
Then develops into the external ear.
Label the features of the external ear in orange.
Helix
Auricular tubercule
Antihelix
Helix
Label the features of the external ear in pink?
Antitragus
Lobule of ear
Intertrgaic incisure
Tragus
Label the features of the external ear in green.
Cavum conchae
Anterior notch
Crus of helix
Crura of antihelix
Label the features that are normally visible when looking at the tympanic membrane via otoscopy.
Handle of malleus
Umbo (end of malleus)
Annulus fibrosus ( thickened peripheral ear of pars tensa)
Light reflex
Orifice of the eustachian tube
Lateral process of the malleus
What are the two main portions of the ear drum?
Pars tensa - majority of ear drum, tense, below malleus prominence
Pars flaccida - upper/attic portion, flacid below the malleus prominence
What is the usefulness of the cone of light in the eardrum?
Points anterior inferiorly - used to indicate what ear looking at
How to identified a retracted or bulging eardrum from appearance?
Retracted - view more of ossiciles (not just malleus)
Bulging - less or no of malleus visible
What structures neighbour the middle ear and can be at risk of erosion during otitis media?
Inferior - bulb of jugular vein
Facial nerve canal
Carotid canal - and contained internal carotid artery
Temporal bone - into the meninges (risk of meningitis)
Mastoid bone - mastoiditis
What are the three different ossicles?
Malleus
Incus
Stapes
What is the role of the endolymphatic duct in the ear?
Drains the continuously produced endolymphatic fluid from the vestibular apparatus and auditory apparatus.
What is the purpose of having semicircular canals on both sides of the head?
Three canals on each side
Each canal is at a different angle.
Horizontal - align on each side
Anterior and posterior canals on opposite sides align
One of the pair gives a negative signal one gives a positive signal - confirm movement.
How can defects in the semicircular canals affect vision?
Unable to fix gaze on item, particularly when head moving
Nystagmus - flickering eye movements (can make feel dizzy)
Where do nerves leave the internal auditory meatus into the cranium?
What nerves?
Consists of mainly the facial nerve CN7, Vestibulocochlear nerve CN8 (c for cochlear, and vestibular)
Located in the petrous portion of the temporal bone
What are some red flags in a patient history for ear problems?
Otalgia (ear pain)
Bleeding
Unilateral otitis media >18yrs (fluid build up), can be caused by blocked eustachian tube indicate tumour at back of nose
Refer for two week wait appointment
What are some important symptoms to consider in an ear clinical history?
Discharge
Hearing change
Tinnitus - perception of sound that does not have an external source
Vertigo/dizziness
Aural fullness - ear pressure or clogging sensation
How does pH relate to acute otitis external?
Norm acidic
More alkaline - risk of infection - commonly caused by shampoo or chlorine in ear
Give are the basic features of acute otitis externa.
External ear disease
More common in adults
Presents with itch and pain
Frequent in swimmers
Usually caused by a Pseudomonas infection or staph aureus
What is the basic treatment for acute otitis external?
Cleaning - microsuction
Topical ear drops - ciprofloxacin +/- dexamethasone
Swab for analysis
Advise aural hygeine - keep ear dry
If gross ear canal swelling may need a wick (tube/structure to help drops get into ear past swelling).
What are some risk factors for acute otitis media?
Children - eustachian tube is more horizontal, narrow and shorter so easier for viral infection/inflammation to spread up, also immature immune system
What is a common cause of acute otitis media?
Viral infection in the nasopharynx spread up the eustachian tube, creates a superimposed pyogenic bacterial infection in middle ear (often Haem, influenza or streptococci)
Describe how acute otitis media leads to discharge.
Inflammation in middle ear
Increased pressure
Pain
Perforation of eardrum
Discharge and relief from pain
What is the common treatment for acute otitis media?
Pain relief
Delayed oral and ear drop antibiotics - between 48-72hrs - poor evidence and norm viral in cause
Surgery if complications e.g tympanoplasty, or incision to drain pus.
What are some complications of acute otitis external?
Fungal infection - otomycosis
Necrotising Otitis externa
What is otomycosis?
A complication of acute otitis external - particularly if lots of topical antibiotics
A fungal infection presents as severely itchy
Asperigillus cause will have yellow-black spores
Candida - thick white cream
What is necrotising otitis externa?
Infection in the external ear canal spreads through soft tissue and can erode the surrounding bone.
Osteomyelitis (inflammation of bone and bone marrow) of the temporal bone.
Presents with severe ear pain, high risk of complications.
Often results from pseduomonas infection.
What are some risk factors for necrotising otitis externa?
Recurrent or persistent otitis externa
Diabetes
Immunosuppression
Elderly
Ear syringing
What is the basic management strategy for necrotising otitis external?
Protracted course of systemic antibiotics
Topical antibiotic drops
Regular microsuction
Diabetes control
What is a cholesteatoma?
Accumulation of benign keratinizing squamous cells in the middle ear - cells are hyperproliferating and secete enzymes which can be locally destructive.
Commonly seen in attic of tympanic membrane
Debris can become infected causing chronic ear discharge
Requires surgery.
What are the potential complications of a cholesteatoma?
Erosion of bone by activating osteoclasts, epithelium proliferate and invade destroying temporal bone and carrying infection to bone/soft tissues
- facial palsy due to necrosis of facial nerve
- intercranial sepsis
- meningitis
How do patients with cholesteatoma present?
Painless otorrhea - foul smeeling
Ache behind ear
Sense of pressure in ear
Conductive hearing loss
History of repeated ear infections
What are the two broad causes of a cholesteatoma?
Congenital - persistent epithelial cell left in the middle ear during embryonic development
Acquired - eustachian tube dysfunction in TM retraction -> effect keratin migration -> trapped keratin.
What are the key features of acute otitis media?
Middle ear disease
More common in children
Usually follow a URTI (usually viral)
Causes pain, then perforation and discharge with pain relief in the ear.
What might acute otitis media look like during otoscopy?
Bulgin of the tympanic membrane due to fluid build up
More opaque in appearance - loss of view of malleus.
What are some common complications of acute otitis media?
Build up of pressure can erode through nearby bone
Perforation of tympanic membrane
Hearing loss
Vertigo
Intra-cranial infection
Acute mastoiditis
CNVII palsy
Intracranial complications
Other abcesses
How does perforation of the tympanic membrane present?
Intense pain in ear with significant discharge from ear