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Mastoiditis

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Overview

Mastoiditis is the inflammation and bony destruction of the mastoid bone. It is usually secondary to the spread of infections from the middle ear. It is a medical emergency and can lead to intracranial infections.

Epidemiology

  • Incidence is lower in developed countries
  • Incidence in developed countries is around 6 per 100,000

Causes

The most common organisms are:

  • Streptococcus pneumoniae – most common
  • Streptococcus pyogenes
  • Staphylococcus species
  • Pseudomonas aeruginosa

Risk Factors

Presentation

The red-flag symptom of mastoiditis is postauricular tenderness (pain behind the ear). Other features are:

  • Fever
  • Systemic upset – the patient often looks very unwell
  • Swellings, red, boggy and tender mass behind the ear
  • The ear may protrude forward
  • Tympanic membrane may be perforated and there may be associated discharge

Differential Diagnoses

Chronic suppurative otitis media

  • Persisting inflammation and draining discharge for >2 weeks
  • The tympanic membrane is usually perforated
  • No fever or ear otalgia
  • No tenderness and/or swellings behind the ear over the mastoid process

Otitis media with effusion (glue ear)

  • Fluid in the middle ear in the absence of signs/symptoms of an infection
  • Effusion is seen with an air-fluid level/bubbles behind a normal tympanic membrane
  • Patients usually present with conductive hearing loss
  • No tenderness and/or swellings behind the ear over the mastoid process

Acute otitis media

  • May precede otitis media with effusion
  • Pain and signs of infection present e.g. fever/malaise/irritability
  • No tenderness and/or swellings behind the ear over the mastoid process

Chronic suppurative otitis media

  • Persisting inflammation and draining discharge for >2 weeks
  • The tympanic membrane is usually perforated
  • No fever or ear otalgia
  • No tenderness and/or swellings behind the ear over the mastoid process

Otitis externa

  • There is no fluid in the middle ear
  • The tympanic membrane is not bulging
  • There may be tenderness of the tragus and pinna – movement is usually painful
  • No tenderness and/or swellings behind the ear over the mastoid process

Investigations

All patients

Initial diagnosis is clinical, patients should immediately be referred to hospital for IV antibiotics if mastoiditis is suspected. Further tests may include:

  • Full blood count (FBC):
    • May show raised white cells
  • ESR and CRP:
    • May be raised
  • CT scanning:
    • Can help diagnose mastoiditis and identify abscess formation
  • Audiograms:
    • Used after treatment to assess hearing loss

Management

All patients

  • Immediate referral to hospital
  • 1st-line – broad-spectrum IV antibiotics

Complications

Prognosis

  • Prognosis is very good with early diagnosis and management
  • If untreated, it can lead to significant morbidity/death

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