Acute Mastoiditis

Risk factors

• Recent or current acute otitis media, especially untreated or inadequately treated
• Recurrent otitis media or chronic suppurative otitis media
• Cholesteatoma
• Immunocompromise, diabetes mellitus
• Age younger than 2 years

Pathophysiology

AOM leads to mucosal inflammation and obstruction of the aditus ad antrum, the narrow channel connecting the middle ear to the mastoid antrum. Trapped pus accumulates within the air cells and, if unresolved, causes osteolytic destruction of the bony septa (coalescent mastoiditis). Pus can then track to the postauricular subperiosteal space (subperiosteal abscess), through the digastric ridge (Bezold abscess in the neck), or intracranially (epidural abscess, sigmoid sinus thrombosis, meningitis, brain abscess).

Clinical presentation

Differential diagnosis

• Severe AOM without mastoiditis — Otalgia and middle ear effusion without postauricular swelling, auricular protrusion, or CT mastoid air-cell opacification with bony destruction
• Postauricular lymphadenitis — Tender mobile node behind the ear without auricular displacement or middle ear findings
• Furuncle of the ear canal — Localized tenderness on tragal pressure; pus from canal; no mastoid tenderness or effusion
• Cholesteatoma with chronic mastoiditis — Chronic foul otorrhea, retraction pocket or attic perforation, often Pseudomonas; CT shows soft tissue and ossicular erosion
• Postauricular cellulitis from skin source — Skin erythema without protrusion of pinna or middle ear disease
• Parotitis — Swelling anterior and inferior to the ear, displaces the lobule outward and upward, but does not push the entire pinna forward

Diagnostic workup

Diagnostic algorithm

flowchart TD
  A[Acute otitis media<br/>not improving] --> B[Postauricular pain/swelling<br/>+ protruding auricle?]
  B -->|Yes| C[CT temporal bone<br/>with contrast]
  C --> D{Coalescent disease<br/>or subperiosteal abscess?}
  D -->|No| E[IV antibiotics<br/>+ myringotomy<br/>observe 48 h]
  D -->|Yes| F[IV antibiotics<br/>+ mastoidectomy<br/>+ abscess drainage]
  E --> G{Improved?}
  G -->|No| F
  G -->|Yes| H[Transition to PO abx<br/>3-4 weeks total<br/>+ ENT follow-up]
  F --> H
  B -->|No| I[Treat as severe AOM<br/>reassess in 48-72 h]

Treatment

Complications

• Subperiosteal abscess; Bezold abscess (pus in upper neck along sternocleidomastoid)
• Facial nerve palsy
• Labyrinthitis with sensorineural loss and vertigo
• Sigmoid (lateral) sinus thrombosis — headache, fever, papilledema
• Meningitis, epidural or brain abscess
• Petrous apicitis (Gradenigo syndrome: otorrhea, retro-orbital pain, abducens palsy)

PANCE pearls

• Persistence or recurrence of AOM symptoms beyond 10-14 days should raise suspicion for mastoiditis.
• The pinna in mastoiditis is pushed forward and outward — in parotitis the earlobe is pushed up and out.
• CT temporal bone is the imaging study of choice; do not delay surgery if subperiosteal abscess is present.
• Always evaluate for intracranial complications when fever, headache, or neurologic findings persist.
• Pseudomonas is common in chronic mastoiditis and after long courses of topical or oral antibiotics.

References

• AAO-HNS — American Academy of Otolaryngology-Head and Neck Surgery clinical practice guidelines on AOM and complications
• AAP — American Academy of Pediatrics clinical practice guideline: The diagnosis and management of acute otitis media (Lieberthal et al., Pediatrics 2013)
• IDSA — IDSA practice guidelines for management of bacterial meningitis (relevant for intracranial extension)