Acute Otitis Media (AOM)

Definition

• Cummings Otolaryngology Head and Neck Surgery
• Harrison's Principles of Internal Medicine 22E (2025)

Epidemiology

• AOM is the most common bacterial infection of childhood: ~85% of all children experience at least one episode.
• Incidence peaks at 6-24 months of age; by age 6, approximately 60% of children will have had at least one episode.
• One third of children with a viral upper respiratory tract infection (URTI) develop AOM within four weeks of its onset.

• Young age and male sex
• Bottle-feeding (non-breastfeeding)
• Daycare attendance (especially with 4+ other children)
• Crowded living conditions or household smoking
• Prematurity and low birthweight
• Having siblings (family history of OME)
• Medical conditions: cleft palate, Down syndrome, cystic fibrosis, ciliary dyskinesia, immunodeficiency
• Shorter, more horizontal Eustachian tube anatomy in young children (anatomical predisposition)
• Cummings Otolaryngology, Tintinalli's Emergency Medicine, Scott-Brown's Otorhinolaryngology Vol. 2

Pathogenesis

1. Viral URTI (rhinovirus and RSV most common; also adenovirus, coronavirus, parainfluenza, human metapneumovirus, enteroviruses)
2. Nasopharyngeal inflammation, altered mucous properties, and reduced mucociliary clearance in the nasopharynx, middle ear, and Eustachian tube
3. Eustachian tube dysfunction - in young children, the tube is shorter and more horizontal, facilitating fluid accumulation
4. Changes in bacterial adherence properties, allowing nasopharyngeal bacteria to ascend into the middle ear
5. Secondary bacterial superinfection of the middle ear

• Scott-Brown's Otorhinolaryngology Vol. 1

Microbiology

• Cummings Otolaryngology, Tintinalli's Emergency Medicine

Clinical Features

• Ear pain (otalgia) - the cardinal symptom; in infants, may manifest as irritability or ear-pulling
• Fever
• Otorrhea (if tympanic membrane has perforated)
• Anorexia
• Conductive hearing loss

• Bulging tympanic membrane (most specific sign) - moderate to severe bulging is diagnostic
• Erythema (redness) of the tympanic membrane
• Cloudy/opaque membrane with obscured landmarks
• Immobility of the tympanic membrane on pneumatoscopy, Valsalva maneuver, or swallowing

• AOM should be diagnosed in children with moderate to severe bulging of the tympanic membrane OR new-onset otorrhea not due to otitis externa
• With mild bulging, AOM can be diagnosed if symptoms have been present <48 hours OR there is intense tympanic membrane erythema
• AOM should NOT be diagnosed without evidence of middle-ear effusion

• Tintinalli's Emergency Medicine, Cummings Otolaryngology

Treatment

Pain Management

• NSAIDs or acetaminophen are effective for mild-to-moderate pain
• Topical agents (benzocaine, procaine, lidocaine) may provide brief additional benefit

Antibiotic Therapy

• NNT = 20 to reduce pain by day 2-3 (antibiotics do not hasten early resolution of pain)
• NNH = 14 for adverse effects (vomiting, diarrhea, rash)
• NNT = ~5,000 to prevent one case of mastoiditis

• <2 years or severe symptoms: 10 days
• 2-5 years, mild-moderate: 5-7 days
• ≥6 years, mild-moderate: 5 days

• Tintinalli's Emergency Medicine, p. 298

Surgical Management

• Tympanocentesis / Myringotomy: Obtains culture material, reduces bacterial load, and provides drainage; indicated for complicated AOM
• Ventilating tubes (tympanostomy tubes): Indicated for recurrent AOM (≥3 episodes in 6 months or ≥4 episodes in 1 year) or persistent middle-ear effusion >3 months
• Cortical mastoidectomy: Required when mastoiditis is suspected; CT scan should be obtained first

Complications

Extracranial Complications

• Acute mastoiditis - most common serious complication; suggested by post-auricular tenderness, swelling, or ear protrusion
• Facial nerve paralysis - occurs due to suppuration behind an intact TM; pathology involves erosion of the bony Fallopian canal or congenital canal dehiscence (found in ~56% of temporal bones). Treatment: wide myringotomy + systemic antibiotics ± mastoidectomy. Usually full recovery.
• Labyrinthine fistula
• Petrous apicitis
• Abscess formation (subperiosteal, Bezold, temporal root)

Intracranial Complications

• Meningitis
• Intraparenchymal, epidural, or subdural abscess
• Lateral sinus thrombosis
• Otitic hydrocephalus

Long-term Sequelae

• Otitis media with effusion (OME / glue ear) - each AOM episode increases the odds of developing OME by ~12x, though this risk resolves after 3 months
• Conductive hearing loss
• Tympanic membrane perforation (chronic)
• Cholesteatoma

• Cummings Otolaryngology, Scott-Brown's Otorhinolaryngology Vol. 2, Harrison's Principles of Internal Medicine 22E

Key Takeaways

1. AOM is the most common childhood bacterial infection, peaking at 6-24 months
2. It typically follows a viral URTI via Eustachian tube dysfunction
3. Main pathogens: S. pneumoniae, H. influenzae, M. catarrhalis
4. Diagnosis requires evidence of middle-ear effusion PLUS signs/symptoms of acute infection
5. Watchful waiting is appropriate for older children with mild disease; antibiotics are indicated for severe disease, young infants, and bilateral findings
6. First-line antibiotic: high-dose amoxicillin (90 mg/kg/day)
7. Tympanostomy tubes are reserved for recurrent or persistent cases
8. Complications include mastoiditis, facial palsy, and intracranial spread - all are serious and require prompt management