ENT Flashcards
What is Otitis Externa?
An inflammation of the external ear canal and can be either acute or chronic in nature
What is the difference in the history between acute OE and chronic OE?
Acute otitis externa lasts less than 3 weeks whereas chronic otitis externa lasts more than 3 months.
What are the 2 classifications of OE?
Localised otitis externa is an infection of a hair follicle in the ear which can develop into a boil. Diffuse otitis externa is widespread inflammation of the skin and subdermis.
What is malignant OE?
When the infection spreads to the mastoid and temporal bones causing osteomyelitis
Name some causes of OE.
Bacterial infection – most commonly Pseudomonas Aeruginosa or Staphylococcus Aureus. The bacteria usually enter the ear after 1 of 4 events:
Blockage of the canal
Absence of cerumen due to excess cleaning
Trauma
Alteration of pH within the canal.
Name some risk factors of developing OE.
Hot and humid climates Swimming Older age Diabetes Mellitus Narrowing/obstruction of the auditory canal Over-cleaning leading to a lack of wax in the canal Wax build-up Eczema Trauma Radiotherapy to the ear
What will a parent describe in the history of a child with OE?
Pain
Itching
Discharge
Hearing loss
What will an examination of OE reveal?
Oedema
Erythema
Exudate
Mobile tympanic membrane
How do you manage OE?
Avoid getting the ear wet use a cap for showering and swimming
Remove any discharge by gently using cotton wool, DO NOT put cotton buds into the ear
Remove any hearing aids and earrings
Use painkillers – paracetamol and ibuprofen
Name some complications of OE.
Abscesses
Stenosis of the ear canal due to a build-up of thick, dry skin
Perforated ear drum
Cellulitis
Malignant otitis externa – infection spreads to mastoid and temporal bones
What is acute mastoiditis a complication of?
Otitis media
How does acute mastoiditis occur?
It occurs due to otitis media infection spreading to involve the bone of the mastoid air cells directly.
In acute mastoiditis, where can the sub-periosteal abscess be found?
- Behind the pinna in an area known as Macewen’s triangle, or higher
- Superior to the pinna towards the zygomatic process
- Over the squamous temporal bone
Name 3 risk factors for developing acute mastoiditis.
More common in young children
Immunocompromised patients
Pre-existence of cholesteatoma
Name some investigations that could be performed in acute mastoiditis.
Ear swab – if discharging ear or post-aural abscess is oozing; sent for MC+S
Blood tests – raised inflammatory markers including WCC and CRP
CT head and mastoid with contrast is indicated in all cases of mastoiditis apart from cases of simple uncomplicated mastoiditis.
Describe the management of acute mastoiditis.
The initial management of acute mastoiditis is intravenous antibiotics as an inpatient. The choice of antibiotic will be based on local guidelines but should cover likely causative organisms including Streptococci and Staphylococcus aureus; high-dose co-amoxiclav or ceftriaxone are usually chosen.
Name some complications of acute mastoiditis.
Extracranial:
Facial nerve palsy Hearing loss – conductive and sensorineural Labyrinthitis Subperiosteal abscess Cranial osteomyelitis Intracranial:
Intracranial infections including meningitis; epidural, temporal lobe or cerebral abscess; subdural empyema
Dural sinus thrombosis
Describe the pathophysiology of acute otitis media.
Bacterial infection of the middle ear results from nasopharyngeal organisms migrating via the eustachian tube.
Name the most common causative organisms of acute otitis media.
Common causative bacteria include S. pneumoniae (most common), H. influenza, M. catarrhalis, and S. pyogenes, all common upper respiratory tract microbiota. Common viral pathogens are respiratory syncytial virus (RSV) and rhinovirus.
Name some risk factors of acute otitis media.
- Age (6-15 months)
- Gender (boys)
- Smoking
- Bottle feeding
- Craniofacial abnormalities
Describe the common symptoms of acute otitis media.
pain, malaise, fever, and coryzal symptoms
Why is it important to test and document the function of the facial nerve in acute otitis media?
due to its anatomical course through the middle ear
Describe the management of acute otitis media.
All patients should be treated with simple analgesics in the first instance. There is no need to treat with antibiotics in most cases and a ‘watch and wait’ approach can be taken provided there are no worrying features
For cases of mastoiditis, if the patient does not improve with IV antibiotics, what is the next line of management?
Mastoidectomy
Describe the aetiology of otitis media with effusion.
In children, otitis media with effusion is usually caused by a combination of chronic inflammatory changes and Eustachian tube dysfunction.
Name some risk factors of developing otitis media with effusion in children.
Bottle fed
Paternal smoking
Atopy (e.g eczema, asthma)
Genetic disorders
Mucociliary disorders, such as Cystic Fibrosis or Primary Ciliary Dyskinesia
Craniofacial disorders, such as Downs Syndrome