Description

• Clinical manifestations of mastoiditis typically appear days to weeks after the first middle ear symptoms.
• Subdivided according to pathologic stage:
  • Acute mastoiditis with periostitis (incipient mastoiditis): purulent material in the mastoid cavities; symptom duration typically ≤1 month
  • 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

The highest incidence in children aged <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

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 periosteitis).
• 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 (2)
• AOM: Streptococcus pneumoniae, nontypeable Haemophilus influenzae
• Acute mastoiditis: S. pneumoniae (most common), group A Streptococci—Streptococcus pyogenes, Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), H. 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 led to higher incidence of mastoiditis as complication of AOM.

Risk Factors

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

General Prevention

• Ensure immunizations (particularly pneumococcal vaccine) are up-to-date.
• Referral to ENT for chronic otitis media
• Appropriate diagnosis and treatment of AOM; prevent recurrent AOM.
• 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

AOM