Key Facts

Acute otitis media (AOM) is an infection of the middle ear cleft, one of the most common childhood infections. It is usually preceded by a viral upper respiratory tract infection and may be complicated by bacterial superinfection. Most cases are self-limiting.

Epidemiology

• >80% of children experience at least one episode by age 3
• Peak incidence: 6-15 months
• More common in winter months
• Risk factors: daycare attendance, bottle feeding (vs breastfeeding), parental smoking, male sex, Down syndrome, cleft palate
• Recurrent AOM (≥3 episodes in 6 months or ≥4 in 12 months) affects 10-20% of children

Aetiology

• Viral (often initial trigger): RSV, rhinovirus, influenza, adenovirus
• Bacterial: Streptococcus pneumoniae (30-40%), non-typeable Haemophilus influenzae (20-30%), Moraxella catarrhalis (10-15%), Group A Streptococcus
• Often polymicrobial (viral-bacterial co-infection)

Pathophysiology

• URTI causes Eustachian tube inflammation and dysfunction
• Eustachian tube obstruction leads to negative middle ear pressure and fluid accumulation
• Nasopharyngeal bacteria ascend via dysfunctional Eustachian tube
• Bacterial colonisation of middle ear fluid causes acute suppurative inflammation
• Children are predisposed due to shorter, more horizontal, floppier Eustachian tubes
• Mucosal oedema and effusion impair sound conduction (conductive hearing loss)

Acute Otitis Media

• Ear pain (otalgia) — young children may pull at ear or be irritable
• Fever
• Hearing loss (conductive)
• Preceding URTI symptoms (coryza, cough)
• Otorrhoea (discharge) if tympanic membrane perforates (pain often improves after perforation)
• Vomiting and irritability (especially in infants)

Otoscopic Findings

• Bulging, erythematous, opaque tympanic membrane
• Loss of light reflex
• Loss of TM landmarks
• Air-fluid levels or bubbles behind TM (early stage/resolving)
• Perforation with mucopurulent discharge

Otitis Media with Effusion (Glue Ear)

• Often asymptomatic or noticed as hearing difficulty
• Amber or dull TM with visible fluid level or bubbles
• Retracted TM
• No acute inflammatory signs

Red Flags

• Mastoid tenderness/swelling/erythema (acute mastoiditis)
• Facial nerve palsy (complications)
• Signs of meningism
• Persistent high fever despite antibiotics
• Vertigo or nystagmus (labyrinthitis)
• Papilloedema (otitic hydrocephalus)

Bedside

• Otoscopy: gold standard for diagnosis; pneumatic otoscopy shows reduced TM mobility
• Tympanometry: type B (flat) trace in AOM/OME; type C (negative pressure) in Eustachian tube dysfunction
• Temperature
• Assessment of hearing (age-appropriate)

Bloods

• Not routinely required for uncomplicated AOM
• FBC, CRP, blood cultures if systemically unwell or suspected complications

Imaging

• CT temporal bones: if mastoiditis or intracranial complications suspected
• MRI brain: if intracranial abscess or venous sinus thrombosis suspected

Special Tests

• Audiometry: if persistent hearing loss (>3 months)
• Ear swab: if chronic discharge or treatment failure
• Pure tone audiometry and tympanometry for OME assessment

Non-pharmacological

• Majority of AOM is self-limiting — resolves within 3-7 days without antibiotics
• Analgesia and antipyretics: paracetamol or ibuprofen
• Delayed (back-up) antibiotic prescription strategy (NICE NG120): collect/use if symptoms worsen or not improving at 3 days
• OME: watchful waiting for 3 months (spontaneous resolution in 50% by 3 months, >90% by 1 year)

Pharmacological

• Immediate antibiotics indicated (NICE NG120):
  • Children <2 years with bilateral AOM
  • Perforation with discharge
  • Systemically unwell or high-risk features
• First-line: amoxicillin 40mg/kg/day in 3 divided doses for 5-7 days
• Penicillin allergy: clarithromycin 7.5mg/kg BD for 5-7 days
• Second-line (treatment failure): co-amoxiclav 40mg/kg/day for 5-7 days
• Topical antibiotics (ciprofloxacin 0.3% drops): for otorrhoea through perforation/grommet

Surgical

• Grommets (ventilation tubes): for bilateral OME with hearing loss (≥25dB) persisting >3 months (NICE NG233)
• Adenoidectomy: may be combined with grommet insertion in children with recurrent OME or nasal obstruction
• Myringotomy: rarely performed alone
• Cortical mastoidectomy: for acute mastoiditis not responding to IV antibiotics

Referral Criteria

• ENT referral: recurrent AOM (≥3 in 6 months), bilateral OME >3 months with hearing loss, suspected cholesteatoma, complications
• Emergency referral: acute mastoiditis, facial nerve palsy, suspected intracranial complications
• Audiology referral: persistent hearing loss

• >80% of AOM resolves without antibiotics within 3-7 days
• Antibiotics reduce duration by only 1 day on average (NNT = 15 to prevent one case of pain at 2-7 days)
• Acute mastoiditis complicates 0.5% of untreated AOM and 0.2% of treated AOM
• TM perforation: most heal spontaneously within 2-4 weeks
• OME: 50% resolve by 3 months, >90% by 12 months
• Recurrent AOM: affects 10-20% of children; frequency decreases with age
• Language development concerns if prolonged bilateral OME during critical speech development period
• Chronic suppurative otitis media: rare, requires specialist management

NICE NG120 Antibiotic Prescribing Strategy for AOM

Tympanometry Traces

Complications of AOM