The ear

Published on 23/06/2015 by admin

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14.1 The ear

Stuart Lewena, Gervase Chaney

1 Otitis externa usually results from excessive exposure to heat and moisture and is usually very painful. Treatment involves cleaning, keeping dry and topical antibiotics.

2 Acute otitis media is a very common emergency presentation, but not all red ear drums are due to otitis media. Management with adequate analgesia is essential. However, antibiotic use should be restricted to specific circumstances.

3 Discharging otitis media due to chronic suppurative otitis media usually presents with painless and offensive discharge. Treatment is with ear toilet and topical antibiotics. Oral antibiotics have little or no role.

4 Otitis media with effusion is very common in children, but treatment is unnecessary in the majority, with resolution over 3 months.

5 Mastoiditis continues to be a problem in the antibiotic era and in many cases is the first presentation of ear disease. Admission, myringotomy and IV antibiotics constitute the mainstays of medical management.

6 Ear trauma is uncommon. Accidental ear injuries are usually unilateral and isolated. Ear trauma is rare in the first year of life and may indicate non-accidental injury. Haematomas should be removed by aspiration or excision.

Otitis externa

Introduction

Otitis externa includes various conditions from the most common acute diffuse otitis externa (swimmer’s or tropical ear) to otomycosis, localised (furunculosis) or chronic otitis externa. It occurs commonly in hot, humid climates or in the summer of temperate climates. Risk factors also include swimming and other water exposure, local trauma, loss of the protective coating of the ear canal, including cerumen and obstruction of the ear canal. Allergy may also play a role.

History

It may initially present with aural fullness or itch, but usually progresses to pain with or without discharge. The pain is often severe and is worse with chewing.

Otomycosis or fungal otitis externa makes up 10% of cases and has a more insidious onset.

Examination

Oedema and erythema of the canal with serous or purulent discharge is usual. The tragus is tender to manipulation. With increased severity, the canal becomes occluded with periauricular oedema and may progress to otitis externa with cellulitis when the child becomes febrile with a toxic appearance.

Differentiation from acute otitis media with perforation or chronic suppurative otitis media is important. Usually in these conditions, the tragus and canal are not tender and there is no erythema and oedema of the canal.

Acute localised otitis externa (furunculosis) occurs in the posterosuperior aspect on the ear canal. Otomycosis has only mild canal wall inflammation and thick otorrhoea.

Investigations

Investigations are largely unnecessary and rarely alter empiric treatment. The organisms found in diffuse otitis externa are most commonly Pseudomonas aeruginosa and Staphylococcus aureus. Furunculosis is usually S. aureus and otomycosis – Aspergillus or Candida species. Consideration of cultures – aerobic, anaerobic and fungal – is worthwhile in cases resistant to routine therapy or if there is more extensive disease – such as associated cellulitis.

Treatment

Acute diffuse otitis externa is managed with frequent gentle cleaning of the canal, along with avoidance of water (swimming prohibited). Ototopical medications are the mainstay of treatment, usually topical antibiotics such as framycetin/gramicidin/dexamethasone combinations. Ciprofloxacin is also effective. Insertion of a wick or ribbon gauze is also helpful. Close follow up for repeated cleaning with or without wick reinsertion may be required.

Furunculosis treatment is by local heat application and oral antibiotics (flucloxacillin or cephalexin) or incision and drainage. Otomycosis will require canal cleaning and antifungal drops or gentian violet.

Prevention

Keeping the ear canal dry and avoidance of trauma to the canal are the mainstays of prevention.

Complications

Progression to cellulitis of the nearby skin/soft tissue and/or lymphadenitis may occur. Oral antibiotics are usually then indicated, with cephalexin a reasonable first choice, but antipseudomonal antibiotics may be necessary. Progressive cellulitis and a toxic-appearing child will require admission for intravenous antibiotics, including pseudomonas cover. Less commonly, involvement of the parotid gland, temporomandibular joint or base of skull may occur.

Chronic otitis externa may occur, and may be a sign of an underlying dermatological disease such as seborrhoeic or atopic dermatitis.

Acute otitis media

Introduction

Acute otitis media (AOM) is one of the most common primary care paediatric presentations. It occurs as a result of infection of the middle ear cavity by both viral and bacterial organisms. It is frequently over diagnosed and remains a common cause for excessive antibiotic use. Adequate analgesia and a selective approach to antibiotic use are the mainstays of management.

History

Classic symptoms include fever, malaise and ear pain. The pain can be severe and during the night may wake the child. Other systemic features such as nausea and vomiting can occur. In younger children, presentation is often non-specific, with crying and irritability. Eardrum perforation and otorrhoea may occur (see complications). These symptoms may present as a primary complaint or frequently occur in the course of an upper respiratory infection.

Examination

A red, bulging, non-mobile tympanic membrane is the most reliable constellation of signs. Redness of the eardrum is a non-specific finding and may be seen with a high fever or following crying. Alone, therefore, it is not diagnostic of otitis media and is an inadequate finding to make the diagnosis.

Investigations

The diagnosis of otitis media is made solely on clinical grounds and investigations are rarely performed. In cases where tympanostomy has been performed, two-thirds are bacterial-culture positive, with a predominance of Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae.

Treatment

The administration of adequate analgesia is paramount to the management of acute otitis media. Paracetamol alone may not be adequate and the combination with codeine may be required. Topical instillation of lidocaine 2% has been shown to be a useful adjunct for rapid pain control but should be combined with longer-acting oral analgesia. Decongestants and antihistamines have not been shown to be effective and are not recommended.

The majority of cases of otitis media will resolve spontaneously. However, antibiotics continue to be widely used. In an otherwise healthy child over 2 years, most authorities now recommend deferring antibiotic use for 2 to 3 days, and to commence treatment only if the child remains symptomatic at review. Approximately 80% of children will avoid antibiotic use with this approach. Provision of a prescription upfront, with advice to commence antibiotics in 2 to 3 days if the child remains unwell, has been shown to result in approximately 50% of children avoiding antibiotics. Both strategies are reasonable, with the latter chosen in cases where access to timely medical review is uncertain. Early antibiotic therapy continues to be advocated in the very young or those with comorbidity.

Amoxicillin is a reasonable first-line antibiotic choice. The usual recommended dose is 45 to 90 mg kg⁻¹ per day. Amoxicillin + clavulanate is the next choice for poor responders. Cefaclor has a significant rate of serum sickness reactions in children and should not be used.

Topical otic antibiotic preparations may be used instead of oral antibiotics in cases with tympanic membrane perforation or those with intact tympanostomy tubes when purulent otorrhoea is the prominent finding.

Complications

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