Acute otitis media (AOM) is predominantly seen in children aged less than three years, with a peak incidence between six and 11 months. By their first birthday, 60 per cent of children will have suffered at least one episode of AOM, and the condition is the most common reason for antibiotic prescription for children in the US.
Pathogenesis and causative organisms
Acute otitis media (AOM) is part of a spectrum of inflammatory conditions affecting the middle ear. These range from a single episode of AOM, recurrent episodes of AOM, otitis media with effusion (OME or ‘glue ear’) and chronic suppurative otitis media.
AOM is generally preceded by a viral upper respiratory tract infection (URTI) that causes congestion of the respiratory mucosa of the nasopharynx and eustachian tube.
This leads to obstruction of the eustachian tube, especially in the anatomically and functionally immature eustachian tubes found in children less than three years old. This obstruction triggers a middle ear effusion, which becomes secondarily infected with pathogenic bacteria from the nasopharynx.
The most common causative organisms in the UK are Streptococcus pneumonia, Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pyogenes.
Risk factors for the development of AOM are listed in box 1.
|Box 1: Risk factors for acute otitis media in children|
The diagnosis of AOM is made clinically from the history of fever and otalgia (which may present as ear tugging in younger children) that develops rapidly, often after a viral URTI.
Otoscope examination reveals an erythematous and bulging tympanic membrane with impaired mobility. Perforation of the tympanic membrane can occur, with associated purulent ear discharge.
Investigations are rarely required in the evaluation of AOM. Culture of ear discharge generally offers no advantage for the management of AOM as the condition is likely to resolve spontaneously before the results are available.
However, culture of fluid taken directly from the middle ear via tympanocentesis may be useful in immunocompromised children and those aged less than six months, where AOM may be associated with an unusual or more invasive pathogen.
The natural course of AOM is of spontaneous resolution within 24 hours, or 72 hours at most. The use of analgesia/antipyretic medications such as paracetamol or a nonsteroidal anti-inflammatory drug should be recommended to treat pain and fever during this time.
The use of antibiotics is more difficult, given the self-limiting nature of the condition in most cases. Three separate antibiotic prescribing strategies may be used according to the age and clinical assessment of the child.
Immediate antibiotic prescribing strategy
Children under two years with bilateral AOM, and children who present with AOM and ear discharge, have been shown to benefit most from immediate antibiotics. Children who have been initially managed without antibiotics, but who show no improvement after four days should receive antibiotics.
Immediate antibiotics should also be considered for children who are systemically unwell, or are at high risk of complications due to immunocompromise or other past medical history.
No antibiotic prescribing strategy
Most children and their parents can be reassured that antibiotics are generally not required in this condition, and that their use may be associated with side-effects such as nausea and vomiting, rashes and diarrhea, and can contribute to antibiotic resistance. The parents should be advised to re-present if the symptoms worsen or if there is no improvement in four days.
Delayed antibiotic prescribing strategy
In certain situations it may be more practical to provide a delayed prescription for antibiotics. This prescription should be collected if there is no improvement after four days, or there is significant worsening of symptoms at any stage.
If an antibiotic is required, a five-day prescription of amoxicillin should be provided, with the alternative of erythromycin or clarithromycin in children with penicillin allergy. No extra benefit has been demonstrated for the use of longer antibiotic courses (7-10 days) over shorter courses (5-7 days).
Any child with suspected acute complications of AOM (mastoiditis, meningitis or facial nerve paralysis) should be urgently referred for ENT assessment.
|Key learning points|
- Professor Kim Ah See is consultant head and neck surgeon and Dr Louise McMurran is specialist registrar at the Aberdeen Royal Infirmary