Acute otitis media (AOM) and mastoiditis in adults in Primary Care

Background information:

Acute otitis media (AOM) is defined as the presence of inflammation in the middle ear, associated with an effusion and accompanied by the rapid onset of symptoms and signs of an ear infection.

Otitis media with effusion (OME) is defined as the presence of fluid in the middle ear without symptoms and signs of an ear infection.

Acute otitis media (AOM) can be caused by both viruses and bacteria; often both are present at the same time

• The most common bacterial pathogens are Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Streptococcus pyogenes
• since the introduction of the pneumococcal conjugate vaccine, the most common bacterial pathogen may be changing from Streptococcus pneumoniae to Haemophilus influenza.
• The most common viral pathogens associated with AOM are respiratory syncytial virus (RSV) and rhinovirus

Without antibiotic treatment: this is guidance for adults but please note the following, symptoms will improve within 24 hours in 60% of children with acute otitis media (AOM), and will settle spontaneously within 3 days in 80% of children.

A Cochrane systematic review (search date November 2012) identified 12 randomized controlled trials (n = 3317, 3854 AOM episodes) of antibiotic treatment for AOM in children. There was no good evidence for the routine use of immediate antibiotics:

• Although antibiotic treatment led to a statistically significant reduction of children with AOM experiencing pain on days 2–7 compared with placebo, symptoms settled spontaneously in most children (82%), and 20 children needed to be treated to prevent one child experiencing pain on those days.
• Antibiotic treatment led to a reduction of tympanic membrane perforations (numbers needed to benefit one person [NNTB] 33) and the development of AOM in the unaffected ear (NNTB 11), but the reviewers noted that for every 14 children treated with antibiotics, one child experienced an adverse event (such as vomiting, diarrhoea, or rash) that would not have occurred if antibiotics had been withheld.
• The evidence, however, showed that antibiotics are most useful in children younger than two years of age with bilateral AOM, or with both AOM and ear discharge (irrespective of age).
• The authors concluded that the benefits of antibiotic treatment must be weighed against possible harms, including adverse effects and the increased risk of antibiotic resistance in the community.

• Complications of acute otitis media (AOM) include:
  • Recurrence of infection.
  • Hearing loss (usually conductive and temporary).
  • Tympanic membrane perforation.
  • Rarely, mastoiditis, meningitis, intracranial abscess, sinus thrombosis, and facial nerve paralysis.

Persistent or recurrent AOM

• Routine follow up is not required in the absence of persistent symptoms of AOM.
• Persistent AOM is defined as occurring when people return for medical advice with the same episode of AOM, either because symptoms persist after initial management or because symptoms are worsening.ie people with persisting symptoms despite antibiotic treatment
• Recurrent AOM is generally defined as three or more well-documented and separate AOM episodes (with an absence of middle ear disease between episodes) in the preceding 6 months, or four or more episodes in the preceding 12 months with at least one episode in the past 6 months

• Management of persistent or recurrent AOM involves:
  • Reassessing the person.
  • Considering the need for ENT referral or admission, depending on the clinical situation.
  • Considering a first-line antibiotic (if not already prescribed) or a second-line antibiotic if the initial treatment was ineffective.
• Measures to prevent recurrent AOM in adults include avoiding smoking and/or passive smoking

Follow up in Primary Care is required when:

1. no antibiotic prescribing strategy is adopted and there is significant worsening of symptoms or if symptoms are not starting to settle within 4 days of the onset of the illness
2. an immediate antibiotic prescribing strategy is adopted and symptoms persist despite completing a course of antibiotics, or if there is significant worsening of symptoms while on therapy.
3. If discharge from the ear canal (otorrhoea) persists for 2 weeks.
4. If perforation of the tympanic membrane has occurred.
5. If hearing loss persists in the absence of pain or fever.
6. For recurrent acute otitis media.

Consider acute referral via PCAL or routine ENT referral, dependent on clinical condition.

General Principles for Treating Infections in Primary Care (please see specific guidance regarding choices of antibiotics)

This guidance is based on the best available evidence but its application must be modified by professional judgement.

1. A dose and duration of treatment is suggested. In severe or recurrent cases consider a larger dose or longer course
2. Choices are given as Preferred option or Alternative for patients intolerant of the preferred option and 2nd Line for when an alternative is required because of treatment failure
3. Only send microbiology specimens if there is a clinical suspicion of infection. Inappropriate specimens (e.g. routine ulcer swab or routine catheter specimen of urine) lead to inappropriate antibiotic prescribing.
4. Prescribe an antibiotic only when there is likely to be a clear clinical benefit.
5. Consider a no, or delayed, antibiotic strategy for acute self-limiting upper respiratory tract infections 1,A+
6. Limit prescribing over the telephone to exceptional cases.
7. Use simple generic antibiotics if possible. Avoid broad spectrum antibiotics (e.g. co-amoxiclav, quinolones and cephalosporins) when narrow spectrum antibiotics remain effective, as they increase risk of Clostridium difficile, MRSA and resistant UTI's.
8. Avoid widespread use of topical antibiotics (especially those agents also available as systemic preparations).
9. In pregnancy, take specimens to inform treatment, use this guidance alternative or seek expert advice. Penicillins, cephalosporins and erythromycin are not associated with increased risks. If possible, avoid tetracyclines, quinolones, aminoglycosides, azithromycin, clarithromycin, high dose metronidazole (2g stat) unless the benefits outweigh the risks. Short-term use of nitrofurantoin is not expected to cause foetal problems (theoretical risk of neonatal haemolysis). Trimethoprim is also unlikely to cause problems unless poor dietary folate intake, or taking another folate antagonist.
10. We recommend clarithromycin as it has less side-effects than erythromycin, greater compliance as twice rather than four times daily & generic medicines are similar cost. Use erythromycin in pregnancy.
11. Where a ‘best guess’ therapy has failed or special circumstances exist, microbiological advice can be obtained from LTHT Microbiology (Mon-Fri 9am-5pm and Sat and Sun 9am-1pm: 0113 39 23962/28580; Otherwise via LTHT switchboard - ask for the On call Microbiology Registrar)

Note
Note: Doses are oral and for adults unless otherwise stated. Please refer to BNF for further information.
Letters indicate strength of evidence:
A+ = systematic review: D = expert opinion