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BASICS

Definition
Mastoiditis is an inflammatory process of the mastoid bone, most commonly a complication of acute otitis media (AOM).

Pathologic Stages:
- Acute mastoiditis with periostitis (incipient): Purulent material in mastoid cavities; symptoms ≤1 month.
- Coalescent mastoiditis (acute mastoid osteitis): Destruction of bony septae between air cells, abscess cavity formation.
- Masked mastoiditis (subacute): Low-grade persistent infection with bony septae destruction, often in recurrent or inadequately treated AOM.
- Chronic mastoiditis: Linked to failed chronic otitis media treatment, often with cholesteatoma; symptoms last months to years.

EPIDEMIOLOGY

  • Highest incidence in children <2 years old.
  • Population at risk similar to AOM (males, daycare attendance).
  • Less common with up-to-date immunizations and proper antibiotics for AOM.
  • Incidence: 1.2 to 3.8 cases per 100,000 children/year (US).

ETIOLOGY AND PATHOPHYSIOLOGY

  • Mastoid is part of the petrous temporal bone with air-filled cells connected to middle ear via aditus and antrum.
  • AOM inflammation and fluid cause obstruction, trapping purulent material, increasing pressure, destroying bony septae.
  • Infection can spread to periosteum and adjacent head/neck areas forming abscesses (e.g., subperiosteal, Bezold abscess).
  • Common pathogens:
  • AOM: Streptococcus pneumoniae, nontypeable Haemophilus influenzae.
  • Acute mastoiditis: S. pneumoniae (most common), Streptococcus pyogenes, Staphylococcus aureus (including MRSA), H. influenzae, Fusobacterium necrophorum.
  • Chronic mastoiditis: Pseudomonas aeruginosa, S. aureus, anaerobes, polymicrobials; rarely Mycobacterium tuberculosis.
  • Abscess: S. aureus, mycobacteria, Aspergillus.
  • Increased penicillin-resistant S. pneumoniae linked to higher mastoiditis incidence.

RISK FACTORS

  • Recurrent or chronic suppurative otitis media.
  • Cholesteatoma (squamous pearl near tympanic membrane).
  • Immunocompromised states.

PREVENTION

  • Ensure pneumococcal and other immunizations are up-to-date.
  • Early diagnosis and appropriate treatment of AOM to prevent recurrence.
  • Avoid water exposure to ears with AOM.
  • Treat chronic eustachian tube dysfunction; consider pressure-equalization tubes.
  • Early cholesteatoma diagnosis and management.

COMMONLY ASSOCIATED CONDITIONS

  • Acute otitis media (AOM).

DIAGNOSIS

History
- Symptoms: lethargy, fever, poor feeding, recent ear infection, otorrhea, otalgia, mastoid swelling/redness, ear lobe swelling, headache, hearing loss.
- Mastoiditis suspected if AOM symptoms persist >2 weeks.

Physical Exam
- Acute: fever, mastoid tenderness/erythema/edema, postauricular fluctuance, displaced pinna (up/out in >1-year-old, down/out in <1-year-old), AOM signs (possibly TM perforation with discharge).
- Chronic: persistent ear drainage, hearing loss, possibly painless.

Differential Diagnosis
- Scalp infection, parotitis, otitis externa, periauricular cellulitis, bone cysts or tumors, deep neck infections.

Diagnostic Tests
- CBC (elevated WBC), ESR, CRP (may be normal in chronic).
- Blood cultures.
- Tympanocentesis/myringotomy for culture.
- Aspiration of fluctuance for culture.
- Imaging:
- CT temporal bone preferred (sensitivity ~97%) showing air cell opacification, coalescence, cortical erosion, abscess.
- MRI for intracranial complications.
- Bone scan (technetium-99m) more sensitive than CT for osteolytic changes.
- MRA if venous sinus thrombosis suspected.
- Lumbar puncture if meningitis suspected.

TREATMENT

General Measures
- Hospitalization and IV antibiotics for acute mastoiditis.
- Myringotomy ± tympanostomy tubes for drainage.
- Surgery (mastoidectomy) if no response after 3–5 days or for abscess.

Medications
- Empiric IV antibiotics covering: S. pneumoniae (including resistant strains), S. pyogenes, S. aureus (including MRSA), P. aeruginosa.
- Typical regimen:
- 3rd-generation cephalosporin (ceftriaxone 2 g IV q24h or cefotaxime 1-2 g IV q4-8h).
- Plus clindamycin for resistant S. pneumoniae.
- Add vancomycin if MRSA suspected.
- For recurrent AOM or recent antibiotics: piperacillin-tazobactam.
- Adjust doses for renal impairment.
- Oral antibiotics after IV course guided by cultures (e.g., amoxicillin-clavulanate, clindamycin).

Chronic Mastoiditis
- Topical ear drops (ofloxacin, neomycin-polymyxin-hydrocortisone).

ISSUES FOR REFERRAL

  • ENT for all mastoiditis cases.
  • Neurosurgery for intracranial complications.
  • Infectious disease consult for complex antibiotic management.

SURGERY/OTHER PROCEDURES

  • Tympanocentesis to obtain middle ear fluid for culture.
  • Myringotomy with tympanostomy tubes for drainage.
  • Simple mastoidectomy if abscess or failed conservative treatment.

ADMISSION AND DISCHARGE CRITERIA

  • Admit with clinical/imaging evidence of mastoiditis.
  • Avoid water exposure to affected ear.
  • Discharge when afebrile for 48 hours, clinically improved, tolerating oral antibiotics.

ONGOING CARE AND FOLLOW-UP

  • Oral antibiotics for 3 weeks post-IV course; longer if intracranial complications.
  • Monitor hearing loss (audiogram) post-treatment.
  • Follow-up with ENT/neurosurgery as indicated.

PROGNOSIS

  • Good with early diagnosis and treatment.
  • Conductive hearing loss may persist or require surgery.

COMPLICATIONS

Extracranial
- Subperiosteal abscess (most common).
- Bezold abscess (sternocleidomastoid muscle abscess, risk of mediastinitis).
- Osteomyelitis of temporal bone, suppurative labyrinthitis.
- Facial nerve paralysis.

Intracranial
- Epidural, subdural, cerebral abscesses.
- Meningitis, cerebritis, periosteitis.
- Otitis hydrocephalus (benign intracranial hypertension).
- Gradenigo syndrome (6th nerve palsy, 5th nerve pain, suppurative OM).
- Sinus thrombosis (sigmoid, lateral, central venous).

Clinical Pearls

  • Suspect mastoiditis if AOM symptoms persist >2 weeks despite normal TM appearance.
  • Temporal bone CT is diagnostic of choice but use judiciously in children due to radiation.
  • Hospitalize and start IV antibiotics promptly.
  • Early ENT consultation for drainage and possible surgery.
  • Prolonged antibiotic therapy required especially if complications occur.
  • Mastoidectomy needed if no improvement after 3–5 days to prevent intracranial complications.