- Clinical science
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.
- Highest incidence between 6–24 months of age 
Epidemiological data refers to the US, unless otherwise specified.
- The eustachian tube (ET) 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 ET → lack of ventilation and drainage of the middle ear →
Predisposing factors for ET obstruction
Inflammation of the ET mucosa
- Viral URT infection (most common cause)
- Allergic rhinitis
- Mechanical obstruction of the ET
- Infants: shorter, narrower, and more horizontal ET → nasopharyngeal secretions easily reflux into the ET → more prone to developing AOM
- Inflammation of the ET mucosa
Common pathogens 
- 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 
- Viral pathogens 
Risk factors 
General symptoms 
- Otalgia/earache, commonly described as throbbing pain
- Hearing loss in the affected ear
- Otorrhea in the case of a ruptured tympanic membrane (TM)
Typical presentation in infants 
- Incessant crying
- Refusal to feed (anorexia)
- Repeatedly touching the affected ear
- Fever and febrile seizures
Examination findings 
- Bulging tympanic membrane (TM) with loss of landmarks 
- 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 
- Additional findings that may be present:
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” section). Pneumatic otoscopy or tympanometry should be used to confirm the presence of an effusion. 
- The diagnosis of AOM can be made if any of the following features are present: 
Not routinely indicated; consider in severe infection or diagnostic uncertainty.
- CBC: Leukocytosis may be present.
Gram stain and culture of middle ear fluid 
- Indication: patients who do not respond to initial therapy, acutely ill patients, and patients with immune deficiencies 
- 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. 
- Blood cultures: indicated only in severe infection
Evaluation for effusion
Pneumatic otoscopy 
- Indications: clinical uncertainty for AOM and to confirm the presence of middle ear effusion
- Characteristic finding: hypomobility of the tympanic membrane 
- Tympanometry 
Uncomplicated AOM is self-limiting in most children (∼ 80%) and the mainstay of treatment is pain relief and observation. 
- Oral analgesia 
- No sufficient evidence to support the routine use of opioids, decongestants, antihistamines, steroids 
- Systemic antibiotic therapy in AOM is recommended to relieve symptoms and reduce the risk of complications in young infants and in severe infection. 
- Topical antibiotics are not typically recommended for AOM with an intact tympanic membrane.
- Treatment failure is common (due to drug resistance and viral coinfection); If initial treatment is unsuccessful, tympanocentesis should be considered to help guide further therapy.
- The recommended duration of therapy depends on age and antibiotic choice.
- Children 
- Adults: no clear guidance on indications exists; whether to start antibiotics for treatment should be guided by clinical symptoms and underlying risk factors. 
Not every case of otitis media requires treatment with antibiotics. 
|Empiric antibiotic therapy for acute otitis media |
|No antibiotic use in previous 30 days||Antibiotic use in previous 30 days||Penicillin allergy|
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. 
- Not routinely indicated in acute AOM
- Consider for patients with treatment failure or recurrent infection.
- Myringotomy 
- Myringotomy with tympanostomy tube insertion 
- AOM with perforation
Patients with tympanostomy tubes 
- 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 
- If there are complications or systemic illness, oral antibiotics (normally amoxicillin/clavulanic acid ) can be given. 
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
- Definition: inflammation of the mastoid air cells
- Epidemiology: : most commonly occurs in children < 2 years 
- 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)
- Recurrence of otalgia and fever after initial improvement
- Symptoms persist for > 2 weeks
- Tender and edematous mastoid
- Ear displaced laterally and forward
- In advanced stages, the retroauricular sulcus is obliterated and the ear can be pushed forward.
- In chronic mastoiditis, there may be persistent otorrhea.
Initial investigation: CT scan of the temporal bone
- 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 
- Indicated in intracranial complications
- Characteristic findings include increased fluid signal intensity in mastoid air cells.
X-ray of the mastoid 
- Early stage: The air cells appear cloudy and indistinct.
- Advanced stage: A cavity can be seen in the mastoid.
Acute mastoiditis: 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:
- Surgical interventions
- Chronic mastoiditis
- Acute mastoiditis: start empiric antibiotic therapy with levofloxacin or ceftriaxone
- Etiology: Inflammation spreads to the inner ear (labyrinth) through the round window.
- Clinical features
- Epidemiology: Rare complication in the antibiotic era
- Etiology: unclear
- Clinical features: lower motor neuron paralysis of cranial nerve VII
- Cerebral venous sinus thrombosis
- Route of spread: direct spread of infection from the middle ear through the destroyed bone overlying the dura or through an emissary vein
- Clinical features
- Diagnostics: MRI/contrast-enhanced CT
- Treatment: IV antibiotics + drainage + mastoidectomy
We list the most important complications. The selection is not exhaustive.