Ear infections

Aetiology

Most common pathogens: Pseudomonas aeruginosa, S. aureus

Less commonly: S. epidermidis, Proteus spp., E. coli, diphteroids

History

• Otalgia (ear pain)
• Otorrhoea (ear discharge)
• Aural fullness
• Pruritis (itchiness)
• Tenderness
• Hearing loss (due to oedema and debris obstructing EAC)
• If advanced there may be oedema and erythema of the auricle/pinna

Examination

Using an otoscope: EAC erythema, oedema + otorrhoea
+/- Pain on distraction of the pinna
+/- Advanced: periauricular and cervical lymphadenopathy

Management

1. Antibiotic drops:
1st line: Sofradex (framycetin sulphate/gramicidin/dexamethasone)
2nd line and for Pseudomonas: Ciproxin (ciprofloxacin + steroid)

2. Earwick insertion to stent open the EAC if there is occlusion (occlusion shown in right-most picture above)
  - this is important in order to allow the antibiotic to reach the infected tissues
  - earwicks are removed after 48 hours

3. Aural suctioning (atraumatic debridement) with the use of a microscope - if experienced enough

4. Analgesia

5. If exostoses (surfer's ear) present: may need surgical management to stop recurrence of otitis externa

Note: the steroid component in the ear drops helps with decreasing ear canal oedema

Aetiology

Normal function of the pharyngotympanic tube (PT tube) is: 

1. Middle ear aeration to allow pressure equilibration between the atmosphere and the middle ear
2. Mucociliary clearance of the middle ear space
3. While doing above it prevents aspiration from nasopharynx to the middle ear

Underlying pathogenesis is pharyngotympanic (Eustachian) tube dysfunction - leading to pathogens passing from the nasopharynx into the middle ear

AOM is usually preceded by a viral URTI - causes PT tube inflammation & therefore dysfunction
The most common pathogens are:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis

Epidemiology

Peak incidence is is in children aged 3 to 18 months with incidence tapering as a child approaches adolescence

History

• Otalgia
• Fever
• Hearing loss
• Otorrhoea (if ear drum perforation)
• Can have decreased appetite and a concurrent URTI

Note: AOM in children can present with fussiness and irritability and therefore an otoscopic examination should be part of a general paediatric assessment

.

Examination

On otoscopy a bulging tympanic membrane (TM) with erythema can be seen

Management

1. Reassurance with analgesia and watchful waiting is appropriate for the majority of children as 80% will have spontaneous resolution within 2 to 14 days. In certain cases antibiotics are appropriate 1st line treatment e.g. severe illness, <6 months of age and not improved within 48 hours of watchful waiting

2. Oral antibiotics:
1st line: Amoxicillin
2nd line: Erythromycin or co-trimoxazole

In paediatrics:
Drug doses are often given in ranges (e.g. 50 - 100 mg/kg/dose) - always give maximum dosage for their weight
Underdosing, by using lower end of range dosing, is one of the primary causes of failure of treatment

3. Analgesia:
Paracetamol is 1st line
Ibuprofen if no contraindications

Aetiology

• The pathogenesis is essentially PT tube dysfunction

A number of hypotheses exist to explain the above but the following two are most often quoted:
1. PT tube dysfunction leads to loss of pressure equilibration of the middle ear with the astmosphere
 - nitrogen is absorbed by the middle ear mucosa leading to the middle ear having a relatively negative pressure
 - this elicits a transudate secretion by the middle ear mucosa and increased passage of pathogens into the middle ear
 - this leads to chronic inflammation and effusion

2. The initial trigger is inflammation of the middle ear (via AOM and/or ongoing reflux from the nasopharynx into the middle ear via PT tube dysfunction)
 - the inflammation induces a mucin-rich transudate

The following risk factors are thought to worsen PT tube dysfunction:

• Parental smoking
• Absence of breast feeding
• Adenoid hypertrophy
• Day care attendance (increased exposure to pathogens)

Epidemiology

Most common in children up to the age of 15

Prevalence much higher in Maori and Pacific Island children compared to European (see blue box above)

History

• Often asymptomatic
• Commonest complaint = decreased hearing (usually noticed by parent)
• Parents notice poor sleep in child (likely due to sensation of pressure)

Examination

Otoscopy (include pneumatic otoscopy):
Dull grey or yellowish immobile TM
If the TM is clear air-fluid levels can occasionally be seen

In adults flexible nasoendoscopy should be performed to exclude a nasopharyngeal tumour

Investigation

Tympanometry - allows testing of TM mobility and middle ear function (abnormal in OME)

Audiology - conductive hearing loss in OME

Management

Firstly patients are categorised into two groups:

1. High risk group: children at risk for speech, language or learning problems
This includes suspected hearing loss, language delay, autism, developmental delay or uncorrectable visual impairment

2. Low risk group: children with no suspicion of above problems

The low risk group can be managedvia "watchful waiting":

- Review 3 months after diagnosis. If still has OME -> audiology testing and referral to ENT

The high risk group needs ENT review

ENT review
The surgeon will consider placement of tympanostomy tubes (grommets) - see pictures below
Adenoidectomy will also be considered in children