Description

• Inflammation of the mastoid air cells of the temporal bone, generally caused by direct extension of acute purulent otitis media
• Middle ear and mastoid air cells are contiguous via the aditus to mastoid antrum
• Fluid accumulation from closure of channel due to otitis media creates opportunity for infection
• Manifestation ranges from clinically insignificant inflammation of mastoid air cells to infection and destruction of the bone
• Acute mastoiditis:
  • Occurs to some degree in all cases of otitis media
  • Early signs and symptoms are those of acute otitis media
  • Usually secondary to contamination with infectious material trapped in the mastoid by inflammatory obstruction of the channel between middle ear and mastoid air cells
• Acute mastoiditis with periostitis:
  • As infection progresses, periosteum of the mastoid bone is involved, causing periostitis
  • Subperiosteal abscess may be present
• Acute mastoid ostitis (also called coalescent mastoiditis):
  • Progression of the infection within the mastoid air cells leads to destruction of the mastoid trabeculae, causing coalescence of bony trabeculae
  • Mastoid empyema or a draining fistula may be present
  • May progress to severe head and neck complications if untreated
• Masked mastoiditis:
  • Mastoid infection, which lingers after an acute otitis media has been treated
  • May progress to acute or coalescent mastoiditis
• Chronic mastoiditis:
  • Infection lasting >3 mo
• Mastoiditis can be a complication of a primary disorder:
  • Leukemia
  • Mononucleosis
  • Sarcoma of the temporal bone
  • HIV
  • Kawasaki disease
• Mastoiditis more common prior to the use of antibiotics for acute otitis media
• More common in young children and infants

Etiology

• Organisms in acute mastoiditis are similar to those in acute otitis media, but differ in frequency:
  • Streptococcus pneumoniae
  • Group A streptococcus
  • Staphylococcus aureus
  • Haemophilus influenzae
• Gram-negative enteric bacteria most common with chronic mastoiditis:
  • Pseudomonas aeruginosa
  • Escherichia coli
  • Proteus mirabilis
  • Bacteroides species
• Other less common causes:
  • Mycobacterium tuberculosis
  • Aspergillus species in immunocompromised states

• More frequently seen in the pediatric population due to strong association with otitis media
• S. pneumoniae is the most common cause in children