Acute Otitis Media (AOM)

Acute Otitis Media (AOM)

Acute otitis media AKA Acute Suppurative Otitis Media is an acute infection of the middle ear canal. Strictly, it is defined as the first 3 weeks of a process in which the middle ear shows signs and symptoms of acute inflammation. AOM frequently follows an URTI which predisposes to a bacterial infection. Infectious organisms spread to the middle ear through the eustachian tube, external ear if there is traumatic perforation, and blood (uncommon). 60% of AOM cases resolve spontaneously in 24 hours. 80% resolve within 2-3 days. AOM may be initially observed in uncomplicated cases in children > 6 months.

AOM is the second most common disease in children (after URTI). It is the most common infection necessitating treatment for children younger than 5 years old. Some children may get Recurrent AOM, whereby episodes recur up to 5 times a year.

Normal tympanic membrane– pale, pinkish in colour, visualize handle of malleus and cone of light

The tympanic membrane in AOM – slight tympanic membrane bulge, a meniscus of purulent effusion at the bottom of the tympanic membrane, thickened and bulging tympanic membrane

• Risk factors
  • Recurrent URTI, Measles, Diphtheria, or whooping cough
  • Ages 6-24 months of age – the Eustachian tube is shorter and straighter allowing for easier spread of pathogens.
  • Factors contributing to Eustachian Tube Dysfunction
    • Craniofacial or skull base abnormalities e.g. Cleft palate
    • Recurrent URTI, Measles, Diphtheria, or Whooping Cough
    • Allergic Rhinitis
    • Nasopharyngeal Tumor
    • Chronic Rhinosinusitis
    • Tonsilitis and adenoiditis
  • Prematurity
  • Nasal packing
  • Environmental factors
    • low SES (poor housing and overcrowding)
    • Daycare attendance
    • Use of a pacifier
    • Passive smoke exposure
    • Bottle-feeding while lying on the back
  • Smoking
  • Ciliary dysfunction
  • Prolonged nasotracheal intubation
  • Nasogastric tube
• Causative organisms
  • Streptococcus pneumoniae (most common)
  • Haemophilus influenzae
  • Moraxella catarrhalis
  • Gram negative bacilli
  • GBS in infants
  • RSV may precede/predispose to bacterial infection
• Pathophysiology
  • ETD causes negative middle ear pressure
  • Transudative fluid collects and persists in the middle ear space
  • Stagnant fluid = Nidus for Infection, often triggered by an URTI
• Stages of Acute Otitis Media
  • Tubal occlusion: Oedema of the eustachian tube causes blockage leading to absorption of air and negative intratympanic pressure
  • Presuppuration: Pyogenic bacteria spread to the middle ear and cause inflammatory exudates to appear
  • Suppuration: Pus forms in the middle air and to some extent in the mastoid air cells. Tympanic membrane bulges and can rupture.
  • Resolution: Tympanic membrane ruptures releasing pus and relieving symptoms
  • Complication: Resolution does not take place with high virulence or immunocompromised patients causing the disease to spread
• Signs and symptoms in neonates
  • Irritability and crying
  • Difficulty to feed
  • Fever
  • Ear pulling
• Signs and symptoms in older children and adults
  • Fever
  • Otalgia or ear tugging
  • Hearing loss
  • Ear fullness
  • Tinnitus
  • Headache
  • Nausea and vomiting
  • Otorrhea
• Otoscopic findings
  • Bulging and redness of the tympanic membrane
  • Non-mobile tympanic membrane
  • The malleus and umbo are not seen well
  • Perforation of the tympanic membrane (frequently in the posterior or inferior quadrant)
  • Opaque serum-like exudate oozing through the entire tympanic membrane
• Investigations
  • Pneumatic otoscopy (insufflation of the tympanic membrane): for formal diagnosis
    • Immobility
    • Type B (flat) curve
  • Tympanocentesis: Most accurate test. Indications for tympanocentesis are as follows:
    • Neonates < 6 weeks
    • Immunocompromised or immunosuppressed patients
    • Patients who have had a complications necessitating culture
    • Patient with treatment failure.
  • Audiogram
    • CHL < 30dB
  • CT Scan: for complications
  • MRI: particularly for intracranial complications
• Medical Treatment
  • Oral Antibiotics: Amoxicillin/clavulanate or 2nd/3rd Generation Cephalosporin e.g. Cefuroxime, Ceftriaxone or Macrolide e.g. Azithromycin, Clindamycin
    • Standard duration < 6 years: 10 days (except azithromycin which is given for 5 days)
    • Standard duration > 6 years and non-severe: 7- 10 days
  • Adjunctive Therapy
    • Antipyretics and Analgesics e.g. Acetaminophen, NSAIDS
    • Decongestants e.g. Oxymetazoline to reduce edema in the middle ear and promote ventilation of the middle ear
  • Myringotomy and insertion of a Tympanostomy tube is indicated if there are repeated infections
  • Antibiotic prophylaxis for Recurrent AOM
    • Full course antibiotics for 10 days
    • Reduced bedtime dose for 5-6 weeks
• Indications for Myringotomy and insertion of a Tympanostomy
  • Recurrent AOM > 4 episodes in 6 months
  • Recurrent AOM > 5-6 episodes in 12 months
  • Severe otalgia
  • Toxic patients
  • Associated complications
• When can antibiotics be delayed in AOM? Low-risk groups. Symptomatically treated for 48-72 hours
  • 24 months old
  • 6-24 months if the diagnosis is uncertain and the child is clinically well
• What are other indications for antibiotic treatment?
  1. Temperature on physical exam or by history of > 38.2 degrees Celsius by any method within the past 48 hours
  2. Symptoms suggestive of AOM for > 48 hours
  3. Toxic-appearing child
  4. The tympanic membrane of the infected ear not intact: pus discharging
  5. The presence of a chronic condition that may impede the child’s immunity or ability to clear the infection, as judged by the clinician
  6. Another episode of AOM within the past 3 months
  7. Signs of impending perforation in the infected ear: bulging
  8. Co-existing bacterial infection
  9. The family is probably unable to seek medical attention if the child’s clinical status worsens according to the clinician
  10. The child’s parent or guardian cannot gain an acceptable understanding of the protocol according to the clinician or according to them
• Complications Complications are rare since AOM is a benign condition if treated with antibiotics
  • Acute Mastoiditis
  • Subperiosteal abscess
  • Facial paralysis
  • Labyrinthitis
  • Petrositis
  • Extradural abscess
  • Meningitis
  • Brain abscess
  • Lateral Sinus Thrombophlebitis
  • Delayed speech
  • Neck abscess

Acute Mastoiditis

Acute mastoiditis is usually seen as a complication of acute otitis media. Symptoms of mastoiditis occur 1-2 weeks after initial onset of acute otitis media, which may or may not have been treated with antibiotics

• Patient History
  • H/O acute otitis media (ear pain, fever, vomiting)
  • Signs and symptoms
    • Pain and tenderness over the mastoid bone
    • A red bulging tympanic membrane
    • Fever
    • “Outstanding ear” from swelling over the post-auricular crease
    • Abscess over the mastoid bone
    • Appears sick-looking or toxic
    • Facial nerve paralysis (rare cases)
• Treatment
  • Myringotomy (to drain the middle ear)
  • IV antibiotics
  • Incision and drainage or aspiration of post-auricular abscess (over the mastoid process)
  • Mastoidectomy if the patient remains febrile or toxic or their clinical condition worsens