Description

• Clinical manifestations of mastoiditis typically appear days to weeks after the first middle ear symptoms.
• 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 with 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

• Similar to population susceptible to AOM (male, daycare attendance)
• Less common if immunizations up-to-date and antibiotics used to treat suppurative AOM

Incidence
1 to 2 cases per 100,000 children per year in U.S. (1)

Etiology and Pathophysiology

• Subclinical stage begins with AOM and inflammation of mastoid air cells
• Mastoid is part of petrous temporal bone composed of air-filled cells
• Mastoid aditus and antrum form a narrow connection between middle ear and mastoid air cells
  • Fluid in the middle ear can cause obstruction at aditus or antrum, blocking outflow tract of mastoid air cells
  • Edema and accumulation of purulent material most commonly spreads from mastoid air cells to periosteum via mastoid emissary veins with penetration of periosteum (acute mastoiditis with periostitis) (1)
• 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 central nervous system (CNS) complications
• AOM: Streptococcus pneumoniae, nontypeable Haemophilus influenzae
• Acute mastoiditis: Streptococcus pneumoniae (most common), group A streptococci/Streptococcus pyogenes, Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), Haemophilus influenzae, Fusobacterium necrophorum
• Chronic mastoiditis: Pseudomonas aeruginosa, S. aureus, anaerobic bacteria, polymicrobials (organisms present in external ear canal), rarely Mycobacterium tuberculosis
• Abscess: S. aureus, mycobacteria, Aspergillus
• Increased incidence of penicillin-resistant S. pneumoniae infections has gradually lead to higher incidence of mastoiditis as complication of AOM (2)

Genetics
No known genetic pattern

Risk Factors

• Cholesteatoma-appears as squamous pearl in anterosuperior area of middle ear near tympanic membrane (TM)
• Recurrent AOM or chronic suppurative otitis media
• Immunocompromised state

General Prevention

• Ensure appropriate vaccinations (particularly pneumococcal vaccine) are up-to-date.
• Referral to ear/nose/throat (ENT) for chronic otitis media
• Appropriate diagnosis and treatment of AOM; prevent recurrent AOM
  • Chemoprophylaxis for AOM is an area of active research. Consider in children with two episodes of AOM in first six months of life or in older children, three episodes in 6 months or four episodes in 1 year
  • Chemoprophylaxis not currently recommended by American Academy of Pediatrics due to concern for multidrug resistance.
• Wear ear plugs when swimming or showering to keep water out of the ears with AOM.
• Treat chronic eustachian tube dysfunction (pressure equalization tubes).
• Early diagnosis of cholesteatoma

Commonly Associated Conditions

Acute otitis media