Otitis media and externa Flashcards
Define mastoiditis.
Mastoiditis typically develops when an infection spreads from the middle to the mastoid air spaces of the temporal bone.
What is the aetiology of mastoiditis?
Bacterial otitis media extends into the mastoid air cells that are contiguous with the middle ear
What are the clinical features of mastoiditis?
- otalgia: severe, classically behind the ear
- there may be a history of recurrent otitis media
- fever
- the patient is typically very unwell
- swelling, erythema and tenderness over the mastoid process
- the external ear may protrude forwards
- ear discharge may be present if the eardrum has perforated
How is mastoiditis diagnosed?
Clinical features although CT can be done if complications suspected
e.g. pain on palpation of the mastoid bone and bulging of the affected ear due to swelling along with symptoms of otitis media.
How is mastoiditis managed?
Urgent referral to hospital
IV antibiotics - should respond well
If severe:
Cortical mastoidectomy if subperiosteal abscess - aim to drain mastoid antrum and air cells without touching middle ear, ossicles or external meatus.
A post-aural incision - exposes the mastoid process bone and the cortex is removed by drilling.
What are the complications of mastoiditis?
- CNVII palsy
- Hearing loss
- Meningitis
- Extradural abscess
What happens if mastoiditis is left untreated?
Abscess may discharge posterior to the pinna and cause a fistula permanently.
Can alternatively cause a SCM abscess and discharge there.
Also can cause intractanial complications.
What is seen on XR of mastoid in mastoiditis?
opacity and air coalescence
What is the treatment for otitis externa in a patient with diabetes?
Ciprofloxacin to cover for Pseudomonas
Name the structures on this diagram.
Lateral process of the malleus shows that this is the right ear as they always point anteriorly
Pars tensa = stiff bit, Pars flaccida = floppy bit
What type of cells is the tympanic membrane made up of?
Outermost = stratified squamous epithelium
Innermost = part of respiratory system, pseudostratified ciliated columnar epithelium
What is the anterior recess of the ear?
Part between the tympanic mebrane and the TMJ in the ear canal where any fluid may collect
What is the function of the eustachian tube?
Supplies middle ear with fresh air
What pathogens cause otitis externa?
Usually skin commensals
Staph
Other:
* Klebsiella
* E coli
* Pseudomonas
What is the management of otitis externa?
Topical antibiotic +/- combined with a steroid
- NB: if the tympanic membrane is perforated aminoglycosides are traditionally not used. Give oral flucloxacillin if the infection is spreading
Removal of debris - if there is canal debris then consider removal
Ear wick insertion - if the canal is extensively swollen
What is shown?
Complication of untreated otitis externa - needs admission for IV abx
Probably caused by Strep rather than Staph.
Worst complication: osteomyelitis of the skull
What type of otitis externa is this?
Fungal
What is shown?
Otitis media - infection is behind the tympanic membrane
NB: injected membrane, yellowish colour is pus (abscess inside)
What are the main complications of otitis media?
Mastoiditis - if infection spreads posteriorly
Tympanic membrane perforation (shown) - due to increased pressure from fluid.
Brain abscess
Meningitis
What is shown on right?
Right membrane is retracted, yellow discolouration, thinned membrane = otitis media with effusion (“glue ear”)
