Acute otitis media

Acute otitis media (AOM) is a painful infection of the middle ear that most commonly results from a bacterial superinfection with Streptococcus pneumoniae, Haemophilus influenza, or Moraxella catarrhalis following a viral upper respiratory tract infection. AOM is a common infection in children under the age of 2 years and is characterized by an acute onset of symptoms (e.g., otalgia, fever, anorexia) with signs of middle ear inflammation (e.g., bulging tympanic membrane, erythema). Mild unilateral infections can be managed without antibiotics, as they are often self-limiting. Infections in children under 6 months, bilateral AOM, or severe symptoms are usually treated with oral antibiotics. Most children will experience at least one episode before the age of five; in children with recurrent AOM that causes frequent symptoms, myringotomy and insertion of tympanostomy tubes may be considered. The most common complication is acute mastoiditis, but facial palsy, labyrinthitis, and in rare cases, even intracranial abscesses may also occur.

See also “Otitis media with effusion” and “Chronic suppurative otitis media.”

• Highest incidence between 6–24 months of age ^[1]
  • Approx. 60–80% of children ≤ 3 years old experience AOM at least once. The incidence of AOM has been declining since the introduction of the pneumococcal and influenza vaccinations. ^[2][3][4]
  • Slightly higher incidence in boys

References:^[5][6]

Epidemiological data refers to the US, unless otherwise specified.

• The eustachian tube connects the middle ear with the nasopharynx and is lined with cilia, which drain the middle ear secretions into the nasopharynx.
• Obstruction/blockage of the eustachian tube (ET) → lack of ventilation and drainage of the middle ear →
  • Resorption of the air in the middle ear → negative middle ear pressure → retraction of the tympanic membrane → otalgia and conductive hearing loss
  • Accumulation of middle ear secretions → bacterial superinfection → pus in the middle ear → bulging tympanic membrane → severe otalgia, fever
• Predisposing factors for ET obstruction
  • Inflammation of the ET mucosa
    • Viral URT infection (most common cause)
    • Allergic rhinitis
  • Mechanical obstruction of the ET
    • Enlarged adenoids
    • Nasal polyps
    • Cleft palate
  • Infants: shorter, narrower, and more horizontal ET → nasopharyngeal secretions easily reflux into the ET → more prone to developing AOM

References:^[5][6]

Common pathogens ^[2]

• General considerations
  • Coinfection with both bacterial and viral pathogens is common (∼ 66% of cases).
  • Less commonly (27% of cases): solely a bacterial infection
  • Purely viral AOM is rare (< 5%); cases are usually mild and self-limiting.
• Bacterial pathogens ^[2]
  • S. pneumoniae ^[4]
  • Haemophilus influenzae ^[7]
  • Moraxella catarrhalis
  • Group A ß-hemolytic streptococci (in older children)
• Viral pathogens ^[8]
  • Respiratory syncytial virus
  • Parainfluenza virus
  • Influenza virus
  • Rhinovirus
  • Adenovirus

Risk factors for AOM ^[1][8]

• Passive cigarette smoke
• Children who attend daycare centers
• Formula feeding/bottle-feeding ^[9]
• Pacifier use
• Children who have more than one sibling or live in a crowded space
• Male sex
• Family or personal history of AOM
• Anatomic abnormalities
• Feeding in a supine position ^[10]

Older children and adults will most frequently report ear pain; in infants and nonverbal children symptoms can be nonspecific, and may be easily confused with other conditions.

General symptoms ^[8]

• Otalgia/earache, commonly described as throbbing pain
• Hearing loss in the affected ear
• Fever
• Otorrhea in the case of a ruptured tympanic membrane (TM)

Typical presentation in infants ^[1][8]

• Irritability
• Incessant crying
• Refusal to feed (anorexia)
• Repeatedly touching the affected ear
• Fever and febrile seizures
• Vomiting

Examination findings ^[8]

Otoscopy

• Bulging tympanic membrane (TM) with loss of landmarks ^[11]
• Opacification and loss of light reflex
• Retracted and hypomobile TM
• Purulent/serosanguinous discharge in the external auditory canal or visible perforation
• Distinct erythema of the TM ^[8]
• Additional findings that may be present:
  • Yellow spot on the TM ^[12]
  • Cartwheel TM ^[12]
  • Blisters or bullae on the tympanic membrane ^[8][13]

Tuning fork test

• The Weber test and Rinne test can be performed to verify conductive hearing loss secondary to an effusion. ^[14]
  • Weber test: Sound localizes to the affected ear.
  • Rinne test: Air conduction is impaired in the affected ear, while bone conduction remains intact.

AOM is primarily a clinical diagnosis based on characteristic symptoms and otoscopic findings. Other causes of otalgia and hearing loss should be excluded (see “Differential diagnoses”). Pneumatic otoscopy or tympanometry should be used to confirm the presence of an effusion. ^[2]

Diagnostic criteria for AOM in children ^[2][8]

The diagnosis of AOM can be made if any of the following features are present: ^[2]

• Moderate to severe bulging of the tympanic membrane
• New onset of otorrhea not due to otitis externa
• New onset of otalgia AND mild bulging of the tympanic membrane
• Distinct erythema AND mild bulging of the tympanic membrane

Laboratory studies

Not routinely indicated; consider in severe infection or diagnostic uncertainty.

• CBC: Leukocytosis may be present.
• Gram stain and culture of middle ear fluid ^[2]
  • Indication: patients who do not respond to initial therapy, acutely ill patients, and patients with immune deficiencies ^[2][15]
  • Typically acquired through tympanocentesis: the extraction of middle ear fluid through a small-gauge needle.
  • Fluid should also be cultured if there is otorrhea from tympanostomy tubes or a perforated TM. ^[15]
• Blood cultures: indicated only in severe infection

Imaging ^[16]

• Rarely required unless there is clinical uncertainty and/or concerns of complications
• Suspected intracranial complications: MRI brain and temporal bone
• Suspected extracranial complications, e.g., mastoiditis: high-resolution CT temporal bone

Evaluation for effusion

• Pneumatic otoscopy ^[17]
  • Description
    • A pneumatic bulb is attached to the otoscope to allow assessment of tympanic membrane mobility.
    • A seal is formed in the ear canal by the tip of the speculum, and air is forced in by pressing the bulb.
  • Indications: clinical uncertainty for AOM and to confirm the presence of middle ear effusion
  • Characteristic finding: hypomobility of the tympanic membrane ^[18]
• Tympanometry ^[19]
  • Description: a probe is inserted into the ear to generate sound waves and measure pressure in the ear canal
  • Indications: confirmation of middle ear effusion ^[2][19]
  • Characteristic findings
    • High peak pressure reflecting the bulging of the tympanic membrane
    • Flattened curve indicating effusion

• Otitis media with effusion
• Chronic suppurative otitis media
• Trauma
• Foreign bodies in the ear canal
• Referred pain from teeth, sinuses, throat, or jaw
• Herpes zoster oticus

The differential diagnoses listed here are not exhaustive.

Approach ^[2][8]

• Screen patients for acute complications such as mastoiditis and labyrinthitis and treat if present.
• Provide analgesia as needed.
• Consider antibiotic therapy based on the patient's age and clinical features.
  • Children < 2 years of age: Generally give antibiotics.
  • Children ≥ 2 years of age
    • Severe symptoms and/or otorrhea: Give antibiotics.
    • Mild symptoms and no otorrhea: conservative management ^[20][21]
  • Adults: Antibiotics are typically given. ^[22][23]
• Reassess all patients managed conservatively after 48–72 hours; if there is no improvement, give antibiotics.
• Consult ENT for adults with recurrent AOM or persistent otitis media with effusion. ^[22]

Conservative management

Uncomplicated AOM is self-limiting in most children (∼ 80%). ^[1][8]

• Outpatient observation and surveillance of symptoms for 48–72 hours
• Oral analgesia ^[2]
  • Acetaminophen
  • Ibuprofen
• No sufficient evidence to support the routine use of opioids, decongestants, antihistamines, steroids ^[1]

Many patients with AOM can be treated conservatively. ^[8]

Antibiotic treatment

Systemic antibiotic therapy in AOM is recommended to relieve symptoms and reduce the risk of complications in young infants and patients with severe infections. ^[2]

• Topical antibiotics are typically reserved for patients with AOM and tympanostomy tubes (see “Special situations”) or those with chronic suppurative otitis media. ^[24]
• Treatment failure is common (due to drug resistance and viral coinfection); If initial treatment is unsuccessful, consider tympanocentesis to help guide further therapy.
• Typical duration of first-line therapy ^[22]
  • Children < 2 years OR any child with severe symptoms: 10 days
  • Children ≥ 2 years AND no severe symptoms: 5–7 days

Topical antibiotics are generally ineffective in treating AOM unless tympanostomy tubes are present.

Indications

• Children ^[2][8]
  • Age ≤ 6 months
  • Age < 2 years with bilateral AOM ^[1][2][22]
  • Any age with:
    • Symptoms that have not improved after 48–72 hours
    • Severe AOM
    • Signs of severe systemic illness
    • Otorrhea not due to otitis externa
    • Cochlear implants ^[25]
• Adults: Antibiotics (e.g., amoxicillin) are typically given to prevent complications. ^{[1][8][22][23]}

Children with cochlear implants who develop AOM should always be treated with antibiotics.

Regimens

Amoxicillin is the first-line agent in antibiotic-naive patients. A macrolide can be given if the patient is severely allergic to penicillin.

H.influenzae and S.pneumoniae show limited sensitivity towards macrolides and trimethoprim/sulfamethoxazole; these antibiotics should only be used for patients with a proven history of type I hypersensitivity to penicillin. ^[8]

Surgical procedures for AOM

• Indications
  • Not routinely indicated in acute AOM
  • Consider for patients with treatment failure or recurrent infection.
• Procedures
  • Myringotomy ^[8][28]
    • Surgical incision into the tympanic membrane to drain fluid to relieve pressure/pain
    • Consider as an adjunct to antibiotic therapy for severe otalgia and a bulging tympanic membrane ^[2]
  • Myringotomy with tympanostomy tube insertion ^[2]
    • Placement of small tubes into the tympanic membrane to prevent the accumulation of fluid
    • Consider for otitis media with effusion and in children with recurrent AOM ^[2]

Special situations

• AOM with perforated tympanic membrane
  • Usually (> 90%) heals spontaneously with systemic antibiotic therapy (See “Empiric antibiotic therapy for AOM.”) ^[8][29]
  • There is no added advantage of topical antibiotics for AOM with TM perforation unless tympanostomy tubes are present. ^[8][30][31]
  • The ear should be kept clean and dry until the TM has fully healed. ^[32]
• Patients with tympanostomy tubes ^[8]
  • Increased discharge indicates acute infection.
  • Usually caused by the same spectrum of bacterial pathogens, but Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermis are also possible
  • Can be treated with topical antibiotics for 7 days (e.g., ofloxacin , ciprofloxacin/dexamethasone ^[8]
  • If there are complications or systemic illness, oral antibiotics (normally amoxicillin/clavulanic acid ) can be given. ^[8]

Otitis media can spread to affect other local structures (e.g., mastoiditis, labyrinthitis, facial nerve palsy, perforated tympanic membrane) or the intracranial cavity (e.g., meningitis, cerebral venous thrombosis, otogenic abscess).

Risk factors for complications

Complications are rare and are usually only seen in the following cases:

• Highly virulent bacteria (e.g., Group A ß-hemolytic streptococci)
• Immunocompromised patients
• Inadequate dose/duration of antibiotics
• Bacterial drug resistance

Mastoiditis ^[8]

Background

• Definition: inflammation of the mastoid air cells
• Epidemiology: most commonly occurs in children < 2 years ^[33]
• Pathophysiology: infection spreads from the middle ear cavity into the mastoid, which is a closed bony compartment → collection of pus under tension and hyperemic resorption of the bony walls → destruction of the air cells (coalescent mastoiditis) → mastoid becomes a pus-filled cavity (empyema mastoid)

Clinical features of mastoiditis

• Signs and symptoms
  • Recurrence of otalgia and fever after initial improvement
  • Symptoms persist for > 2 weeks
  • Tender and edematous mastoid
  • Ear displaced laterally and forward
  • Obliteration of the retroauricular sulcus in advanced stages
  • In chronic mastoiditis, there may be persistent otorrhea.
• Otoscopy findings: may be normal
  • TM may be bulging and erythematous.
  • May be perforated with otorrhea

Suspect mastoiditis in patients with recent or persistent otitis media and erythema, swelling, and/or pain behind the ear or protrusion of the pinna! ^[34]

Diagnostics for mastoiditis ^[8][34][35]

Mastoiditis is primarily a clinical diagnosis.

• Indications for imaging
  • Symptoms that do not improve after 48 hours of treatment.
  • Suspected intracranial complication
  • Planned surgical interventions
• CT scan of the temporal bone: Initial imaging study (if indicated)
  • Opacification of the mastoid air cells
  • Erosion of the air cell walls
  • Pus in the mastoid cavity (areas of enhancement on CT)
• MRI brain and temporal bone ^[36] Consider as initial modality in children due to lack of ionizing radiation ^[35][36]
  • More sensitive for intracranial infectious complications
  • Characteristic findings include increased fluid signal intensity in mastoid air cells.
• X-ray of the mastoid ^[37][38]
  • Early stage: The air cells appear cloudy and indistinct.
  • Advanced stage: A cavity can be seen in the mastoid.

Management

• Acute mastoiditis ^[26][39]
  • Provide analgesia as needed.
  • Screen for symptoms of sepsis and/or meningitis.
  • Start empiric antibiotic therapy with levofloxacin or ceftriaxone
    • If episode is secondary to an acute exacerbation of chronic otitis media: surgical debridement of auditory canal AND start antibiotic treatment with:
      • Vancomycin
      • OR piperacillin/tazobactam
      • OR vancomycin AND ciprofloxacin
    • Surgical interventions
      • Early infection: myringotomy and tympanostomy tube insertion to facilitate drainage
      • Severe or refractory cases: mastoidectomy (the removal of the mastoid air cells via a postauricular incision to facilitate drainage of pus)
  • Refer to ENT for admission and consideration of surgery. ^[8]
• Chronic mastoiditis
  • Culture ear drainage.
  • Topical fluoroquinolone ear drops, e.g., ciprofloxacin
  • Consult an otolaryngologist for consideration of surgical interventions.

Complications

Untreated, the pus may perforate through the bony walls and cause the following abscesses:

• Postauricular abscess
  • Most common type
  • Pus collects under the skin behind the ear.
  • Pushes the auricle forwards and downwards
• Bezold abscess
  • Pus breaks the tip of the mastoid and dissects into the neck, often collecting behind the sternocleidomastoid
  • Causes neck pain, torticollis, and fever
  • Treatment: IV antibiotics + mastoidectomy + drainage of neck abscess
• Zygomatic abscess
  • Infection spreads to the zygomatic air cells (located at the zygomatic root)
  • Causes swelling in front of and above the auricle
• Brain abscess

Bacterial labyrinthitis

• Etiology: Inflammation spreads to the inner ear (labyrinth) through the round window.
• Clinical features
  • Severe vertigo, nausea, and vomiting
  • Hearing loss
  • Nystagmus direction can be variable ^[40][41]
• Diagnostics
  • Change of lateralization in Weber test
  • Audiometry: sensorineural hearing loss
• Treatment
  • IV antibiotics + tympanostomy with insertion of tympanostomy tube + glucocorticoids
  • Mastoidectomy (to treat the source of infection in AOM)

Peripheral facial palsy ^[42]

• Epidemiology: Rare complication in the antibiotic era
• Etiology: unclear
• Clinical features: lower motor neuron paralysis of cranial nerve VII
• Diagnostics:
  • High-resolution CT of temporal bones to rule out concurrent mastoiditis ^[43]
  • Electroneurography: patients with > 95% degeneration at 3– 14 days after paralysis develops require surgical decompression ^[42]
• Treatment:
  • IV cephalosporin (e.g. cefotaxime or ceftazidime ) ^[42]
  • Corticosteroids ^[44]
  • Surgical decompression of the nerve

Otogenic abscess

• Route of spread: direct spread of infection from the middle ear through the destroyed bone overlying the dura or through an emissary vein
• Types
  • Epidural abscess
  • Subdural abscess
  • Cerebral abscess: The ipsilateral temporal lobe is the most common site (ipsilateral cerebellar abscess is second most common).
• Clinical features
  • Persistent headache and otorrhea
  • Signs of raised ICP
  • Signs of meningeal irritation
  • Focal neurological deficits
• Diagnostics: MRI/contrast-enhanced CT
• Treatment: IV antibiotics + drainage + mastoidectomy

Other intracranial complications

• See “Meningitis.”
• See “Cerebral venous thrombosis.”

We list the most important complications. The selection is not exhaustive.

• Recommend:
  • Exclusive breastfeeding for at least 6 months
  • Smoking cessation for caregivers
• Advise limiting pacifier use and avoiding supine bottle feeding.
• Encourage adherence to the ACIP immunization schedule.

Day care attendance is associated with an increased risk of AOM. ^[2]