What is the definition, classification, pathophysiology, signs, symptoms, and treatment of acute otitis media (AOM) in patients of all ages, particularly children under 5?

Acute Otitis Media (AOM): Comprehensive Overview

Definition

Acute otitis media requires three essential diagnostic elements: (1) acute onset of signs and symptoms, (2) presence of middle ear effusion, and (3) signs and symptoms of middle ear inflammation. 1, 2

The diagnosis is established when:

• Moderate to severe bulging of the tympanic membrane OR new-onset otorrhea (not from otitis externa) is present 1, 2
• Mild bulging with recent-onset ear pain (< 48 hours) OR intense erythema of the tympanic membrane is observed 1, 2, 3

Classification and Types

Primary Classification

• Acute Otitis Media (AOM): Characterized by acute symptoms, middle ear effusion, and signs of inflammation with rapid onset (usually abrupt) 1, 4
• Otitis Media with Effusion (OME): Middle ear effusion WITHOUT acute symptoms or signs of inflammation—fundamentally different from AOM and should not be treated with antibiotics 2, 5
• Chronic Suppurative Otitis Media (CSOM): Persistent drainage through a perforated tympanic membrane 4

Severity Classification for Treatment Decisions

• Severe AOM: Temperature ≥39°C (102.2°F), moderate-to-severe otalgia, or otalgia lasting ≥48 hours 1, 6
• Non-severe AOM: Mild otalgia and temperature <39°C 1, 6

Pathophysiology

AOM develops through eustachian tube dysfunction that prevents proper middle ear ventilation and drainage, typically occurring during or after upper respiratory infections. 5, 7

Microbial Etiology

• Bacterial pathogens: Streptococcus pneumoniae, nontypable Haemophilus influenzae, and Moraxella catarrhalis are the predominant bacteria 7, 6
• Viral pathogens: Respiratory syncytial virus, rhinovirus, adenovirus, parainfluenza, and coronavirus frequently precede or accompany AOM 7
• Bulging tympanic membranes have bacterial pathogens 75% of the time, increasing to 80% when the TM is yellow 1

Signs and Symptoms

Clinical Presentation by Age

In older children:

• Rapid onset of ear pain (otalgia) is the most consistent symptom, present in 50-60% of cases 1, 4, 3
• Fever (though not always present) 4, 3
• Otorrhea 1, 4, 3

In young preverbal children:

• Ear tugging, rubbing, or holding 1, 2, 4
• Excessive crying and irritability 1, 4, 3
• Changes in sleep or behavior patterns 1, 2
• Fever 4, 3
• Anorexia, vomiting, or lethargy 3

Critical Otoscopic Findings (in order of diagnostic value)

Pneumatic otoscopy is essential for diagnosis 2:

1. Tympanic membrane mobility: Distinctly impaired mobility has the highest sensitivity and specificity (95% and 85%, respectively) 1, 2
2. Bulging TM: Highest specificity (97%) for bacterial AOM; moderate-to-severe bulging is the most important diagnostic finding 1, 2
3. Cloudy TM: High sensitivity (74%) and specificity (93%) 1, 2
4. TM color: Hemorrhagic, strongly red, or moderately red correlates with AOM; slightly red TM is NOT diagnostically helpful 1, 2
5. Air-fluid level behind the TM 1, 2

Common Diagnostic Pitfalls

• Clinical history alone is poorly predictive of AOM, especially in younger children 2, 4
• Distinguishing AOM from OME is difficult and commonly leads to unnecessary antibiotic prescriptions when OME is mistaken for AOM 2, 4
• Fever is not required for diagnosis; diagnostic criteria focus on otoscopic findings 4

Treatment and Management

Pain Management (ALWAYS Address First)

Pain management should be addressed in ALL cases regardless of antibiotic use, especially during the first 24 hours. 1

Antibiotic Decision Algorithm

Step 1: Determine if observation without antibiotics is appropriate

Observation option (48-72 hours) is appropriate for: 1, 3

• Children 6 months to 2 years with non-severe illness AND uncertain diagnosis
• Children ≥2 years with non-severe illness OR uncertain diagnosis
• Requires assured follow-up 1

Immediate antibiotic treatment is required for: 1, 6

• ALL children <6 months of age
• ALL children 6 months to 2 years with certain diagnosis OR severe illness
• ALL children ≥2 years with severe illness AND certain diagnosis
• Bilateral AOM in children 6 months to 2 years 6
• Children with otorrhea 6
• Toxic-appearing children 6
• Immunocompromised children 6
• Children with craniofacial abnormalities 6

Antibiotic Selection

Step 2: Choose appropriate antibiotic

First-line therapy: High-dose amoxicillin 80-90 mg/kg/day in two divided doses 1, 3, 8, 6

Amoxicillin-clavulanate instead if: 3

• Amoxicillin used for AOM in previous 30 days
• Concomitant purulent conjunctivitis

For penicillin allergy (non-type I hypersensitivity): 1

• Cefdinir, cefpodoxime, or cefuroxime

For type I hypersensitivity to penicillin: 3

• Cefdinir or azithromycin (based on risk assessment for cephalosporin cross-reactivity)

Treatment Failure

If no response within 48-72 hours, reassess the patient to confirm AOM diagnosis 1

Prevention Strategies

• Pneumococcal and influenza vaccines reduce AOM risk 3
• Exclusive breastfeeding until at least 6 months of age reduces AOM risk 3
• Minimize risk factors including daycare exposure and environmental tobacco smoke 9

Tympanostomy Tube Consideration

Tympanostomy tubes should be considered for: 3

• ≥3 episodes of AOM within 6 months, OR
• ≥4 episodes within 1 year with 1 episode in the preceding 6 months

Epidemiology Context

• By age 3,50-85% of children will have had at least one AOM episode 3, 9
• Peak incidence occurs in the first year of life (45.3 episodes per 100 children per year) 4
• AOM is the most common diagnosis in childhood acute sick visits 3, 9