Acute Mastoiditis

By usmlevideoss

Introduction

Acute mastoiditis is a bacterial infection of the mastoid air cells, typically occurring as a complication of acute otitis media (AOM). It can lead to serious intracranial and extracranial complications if left untreated.

Etiology

The most common pathogens include:

  • Streptococcus pneumoniae
  • Streptococcus pyogenes (Group A Streptococcus)
  • Haemophilus influenzae
  • Moraxella catarrhalis
  • Staphylococcus aureus (including MRSA in some cases)

The infection usually spreads from the middle ear to the mastoid air cells, leading to bone destruction and potential abscess formation.

Epidemiology

  • Most commonly affects children under 2 years old
  • More frequent in patients with recurrent or untreated AOM
  • More prevalent in developing countries due to limited access to antibiotics

Pathophysiology

  1. Acute otitis media (AOM) leads to inflammation and pus accumulation.
  2. The infection spreads to the mastoid air cells through the aditus ad antrum.
  3. Osteolysis of the mastoid bone occurs due to increased pressure and bacterial invasion.
  4. If untreated, it can lead to subperiosteal abscesses, venous sinus thrombosis, and intracranial infections (e.g., meningitis, brain abscess).

Clinical Manifestations

  • Fever and otalgia (ear pain)
  • Postauricular swelling, redness, and tenderness
  • Protrusion of the auricle (ear pushed forward and downward)
  • Otorrhea (ear discharge) if tympanic membrane ruptures
  • Hearing loss (conductive)
  • Irritability, poor feeding (in young children)
  • Severe cases: Signs of intracranial involvement (e.g., headache, altered mental status)

Diagnosis

  1. Clinical Examination – Postauricular swelling, erythema, and auricle displacement.
  2. Otoscopy – Bulging tympanic membrane or perforation with purulent discharge.
  3. Imaging:
  • CT scan of the temporal bone: Destruction of mastoid air cells, abscess formation.
  • MRI (if intracranial complications are suspected).
  1. Laboratory tests: Elevated WBC, CRP, and ESR may indicate infection.

Treatment

  1. IV Antibiotics (Empiric Therapy):
  • Ceftriaxone or Cefotaxime (covers S. pneumoniae, H. influenzae, and M. catarrhalis)
  • If MRSA is suspected → Add Vancomycin
  1. Surgical Management (If Severe or No Response to Antibiotics):
  • Myringotomy with tympanostomy tube placement (for drainage)
  • Mastoidectomy (for cases with abscess or intracranial spread)
  1. Supportive Care:
  • Pain management (NSAIDs, acetaminophen)
  • Adequate hydration

Prognosis

  • Early treatment → Excellent prognosis
  • Delayed treatment → Risk of complications (brain abscess, sigmoid sinus thrombosis, hearing loss)
  • Recurrence possible in chronic cases

SUPERMemory (Mnemonic)

“M.A.S.T.O.I.D.” for Acute Mastoiditis

M – Middle ear infection precedes it (AOM complication)

A – Auricle pushed forward (ear displacement)

S – Swelling behind the ear (postauricular erythema & tenderness)

T – Tender mastoid process

O – Otorrhea (ear discharge if TM perforated)

I – Intracranial complications (meningitis, brain abscess)

D – Diagnose with CT scan (bone destruction)

SUPERPoint

Acute mastoiditis is a complication of acute otitis media, presenting with postauricular pain, swelling, and auricle displacement. Diagnosis is clinical and confirmed with CT. Treatment includes IV antibiotics and, if needed, surgical drainage.

SUPERFormula

Patient presents with postauricular pain & swelling + Auricle pushed forward + Fever + Otorrhea + history of otitis media = Acute Mastoiditis

References

Amdur RL, Linder JA. Upper Respiratory Symptoms, Including Earache, Sinus Symptoms, and Sore Throat. In: Loscalzo J, Fauci A, Kasper D, Hauser S, Longo D, Jameson J. eds. Harrison’s Principles of Internal Medicine, 21e. McGraw-Hill Education;

Coombs CM. Ear and Mastoid Disorders in Infants and Children. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds.Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill Education; 2020.