Ear Infections
Definition | Otitis Externa | Acute Otitis Media | Mastoiditis | References
Definition
Ear infections are inflammatory conditions of the ear, caused by bacterial, viral, or fungal infections. They can affect different parts of the ear, leading to a variety of symptoms and requiring different management approaches.
Otitis Externa
Definition: Otitis externa, commonly known as "swimmer's ear," is an infection of the outer ear canal.
Aetiology: Bacterial infections such as Pseudomonas aeruginosa and Staphylococcus aureus are the most common causes, though fungal infections (e.g., Aspergillus, Candida) can also occur.
Pathophysiology: Moisture trapped in the ear canal promotes bacterial or fungal growth, leading to inflammation and infection.
Risk Factors: Swimming, trauma from cleaning the ear, hearing aid use, and humid environments.
Signs and Symptoms: Ear pain, itching, discharge, hearing loss, and tenderness around the ear. In severe cases, the ear canal may become completely blocked due to swelling.
Investigations: Clinical examination and otoscopy to inspect the ear canal.
Management:
- Otomise spray: First-line treatment containing antibiotics, corticosteroids, and acetic acid to target infection and inflammation.
- Topical antibiotics: For bacterial infection (e.g., gentamicin ear drops).
- Topical antifungals: If fungal infection is suspected (e.g., clotrimazole ear drops).
- Pain management: Simple analgesia like paracetamol or ibuprofen.
- Prevention: Keep the ear dry, avoid inserting objects into the ear.
- Referral: Severe cases, such as necrotising otitis externa, require ENT specialist review.
Acute Otitis Media
Definition: Acute otitis media (AOM) is an infection of the middle ear, typically following a viral upper respiratory infection.
Aetiology: Common bacterial pathogens include Streptococcus pneumoniae and Haemophilus influenzae. Viruses such as RSV and influenza can predispose the middle ear to secondary bacterial infection.
Pathophysiology: Inflammation and fluid accumulation in the middle ear due to Eustachian tube dysfunction, leading to increased pressure and infection.
Risk Factors: Younger children, exposure to tobacco smoke, daycare attendance, and bottle feeding.
Signs and Symptoms: Ear pain, fever, irritability, hearing loss, and in some cases, drainage of fluid if the tympanic membrane ruptures.
Investigations: Otoscopy showing a bulging, red, or immobile tympanic membrane.
Management:
- First-line treatment: Amoxicillin is the recommended antibiotic for bacterial AOM, prescribed for 5-7 days.
- Alternatives: In case of penicillin allergy, consider clarithromycin.
- Pain management: Simple analgesia such as paracetamol or ibuprofen for pain and fever.
- Watchful waiting: For mild cases, particularly in children over 2 years, monitor symptoms as many resolve without antibiotics.
- Referral: If recurrent or complications such as hearing loss arise, refer to ENT for further evaluation.
Mastoiditis
Definition: Mastoiditis is a serious bacterial infection of the mastoid bone, which is located just behind the ear, often following an episode of untreated or inadequately treated acute otitis media.
Aetiology: Extension of middle ear infection into the mastoid air cells, commonly caused by Streptococcus pneumoniae and Haemophilus influenzae.
Pathophysiology: Inflammation spreads from the middle ear to the mastoid bone, leading to the destruction of bone and the formation of abscesses.
Risk Factors: Recent AOM, immunocompromised state, inadequate or delayed treatment of AOM.
Signs and Symptoms: Severe pain behind the ear, swelling and redness over the mastoid process, fever, ear discharge, and hearing loss.
Investigations: Clinical examination, CT scan to assess the extent of infection, culture of ear discharge.
Management:
- Intravenous antibiotics: Empirical treatment with ceftriaxone or co-amoxiclav is typically used until culture results guide therapy.
- Myringotomy: To drain pus from the middle ear, relieve pressure, and improve symptoms.
- Mastoidectomy: Surgical drainage of the mastoid air cells in severe or unresponsive cases.
- Referral: Immediate referral to ENT specialist for urgent management and surgical intervention.
References
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