ENT - Otitis Externa Flashcards
(23 cards)
What is otitis externa?
Inflammation of the skin in the external ear canal
Infection can be localised or diffuse, can spread to pinna
What are the two types of otitis externa based on duration?
- Acute (less than three weeks)
- Chronic (more than three weeks)
What is another common name for otitis externa?
Swimmers ear
What are two predisposing factors for otitis externa?
- Exposure to water
- Trauma from cotton buds or earplugs
Ear wax (cerumen) can protect against infection, removal of ear wax increases infection risk
What may cause inflammation in otitis externa?
- Bacterial infection
- Fungal infection (e.g., aspergillus or candida)
- Eczema
- Seborrhoeic dermatitis
- Contact dermatitis
What are the two most common bacterial causes of otitis externa?
- Pseudomonas aeruginosa
- Staphylococcus aureus
What type of bacteria is Pseudomonas aeruginosa?
Gram-negative aerobic rod-shaped bacteria
What environments does Pseudomonas aeruginosa thrive in?
Moist, oxygenated environments
What are typical symptoms of otitis externa?
- Ear pain
- Discharge
- Itchiness
- Conductive hearing loss (if the ear becomes blocked)
What signs may be observed during examination of otitis externa?
- Erythema and swelling in the ear canal
- Tenderness of the ear canal
- Pus or discharge in the ear canal
- Lymphadenopathy (swollen lymph nodes)
How is the diagnosis of otitis externa made?
Clinically with an examination of the ear canal (otoscopy)
Ear swab can be used to identify causative organism, not normally needed
What treatment is recommended for mild otitis externa?
Acetic acid 2% (available over the counter as EarCalm)
Has antifungal and antibacterial effect
Can be used prophylactically before and after swimming in patientes prone to otitis externa
What are examples of treatments for moderate otitis externa?
- Neomycin, dexamethasone and acetic acid (e.g., Otomize spray)
- Neomycin and betamethasone
- Gentamicin and hydrocortisone
- Ciprofloxacin and dexamethasone
What should be excluded before using topical aminoglycosides in the ear?
A perforated tympanic membrane
As they are potentially otoxic, can rarely cause hearing loss
How is severe otitis externa treated?
Oral antibiotics e.g. flucloxacillin or clarithromycin
What is an ear wick used for?
To deliver treatment when the canal is very swollen
How can fungal infections be treated?
Clotrimazole ear drops
What is malignant otitis externa?
Severe and potentially life-threatening form of otitis externa
Spreads to bones surrounding ear canal and skull, can progress to osteomyelitis of temporal bone
What are underlying risk factors for malignant otitis externa?
- Diabetes
- Immunosuppressant medications (e.g., chemotherapy)
- HIV
What are key symptoms of malignant otitis externa?
More severe than otitis externa
* Persistent headache
* Severe pain
* Fever
What is a key finding in malignant otitis externa?
Granulation tissue at the junction between bone and cartilage in the ear canal
What emergency management is required for malignant otitis externa?
- Admission to hospital under the ENT team
- IV antibiotics
- Imaging (e.g., CT or MRI head)
What complications can arise from malignant otitis externa?
- Facial nerve damage and palsy
- Other cranial nerve involvement
- Meningitis
- Intracranial thrombosis
- Death
