Description

• Clinical manifestations of mastoiditis typically appear 3 weeks after the first middle ear symptoms.
• Stiffness and thickening of the tympanic membrane (TM) is common.
• Acute mastoiditis: symptoms <1 month in duration; subdivided according to the pathologic stages:
  • Acute mastoiditis with periostitis (incipient mastoiditis): purulent material in the mastoid cavities
  • Coalescent mastoiditis (acute mastoid osteitis): destruction of the thin bony septae between air cells; followed by the formation of abscess cavities pus dissecting into adjacent areas
• Masked mastoiditis (subacute mastoiditis): low grade, persistent infection with destruction of the bony septae between air cells; occurs in patients with persistent middle ear effusion or recurrent episodes of inadequately treated AOM
• Chronic mastoiditis: associated with failed treatment of chronic otitis media. Often associated with cholesteatoma; symptoms last months to years.

Epidemiology

Highest incidence in children <2 years

• Routine prescription of antibiotics and routine childhood immunizations have reduced the number of cases of AOM and mastoiditis.

Incidence
1 to 4 cases per 100,000 children per year (1)

Etiology and Pathophysiology

• Subclinical stage begins with AOM and inflammation of mastoid air cells.
• Obstruction of the aditus ad antrum (connecting the tympanic cavity and mastoid)
  • Blocks outflow tract of mastoid air cells
  • Edema and accumulation of purulent material with penetration of periosteum (acute mastoiditis with periosteitis)
• Increased pressure from fluid within the air cells leads to destruction of bony septae (acute mastoid osteitis/acute coalescent mastoiditis).
• Acute mastoid osteitis can spread to adjacent areas in head and neck with abscess formation:
  • Subperiosteal abscess (most common complication), Bezold abscess, suppurative labyrinthitis, suppurative CNS complications
• AOM: Haemophilus influenzae, Streptococcus pneumoniae
• Acute mastoiditis: S. pneumoniae (most common), Streptococcus pyogenes, H. influenzae, Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA])
• Chronic mastoiditis: Pseudomonas aeruginosa, S. aureus, Enterobacteriaceae, anaerobic bacteria, polymicrobials (2)

Genetics
No known genetic pattern

Risk Factors

• Cholesteatoma
• Recurrent AOM or chronic suppurative otitis media
• Immunocompromised state

General Prevention

• Ensure appropriate vaccinations (particularly pneumococcal vaccine).
• Referral to ENT for chronic otitis media
• Appropriate diagnosis and treatment of AOM
• Prevent recurrent AOM.
• Treat chronic eustachian tube dysfunction (pressure equalization tubes).
• Early diagnosis of cholesteatoma