Otitis Media - Acute

Definition

Acute otitis media (AOM) is an acute infection of the middle ear, characterized by rapid onset of signs and symptoms of inflammation, such as ear pain, fever, and hearing loss, often following an upper respiratory tract infection.

Epidemiology

• Most common in infants and children between 6 months and 3 years.
• By age 3, approximately 80% of children experience at least one episode.
• More frequent in winter months and in settings with high respiratory infection exposure.
• Risk factors: daycare attendance, bottle feeding (especially while supine), exposure to tobacco smoke, craniofacial abnormalities (e.g., cleft palate), and family history of recurrent AOM.
• In adults, less common and often secondary to sinus infection or nasopharyngeal dysfunction.

Etiology

• Usually bacterial, following viral upper respiratory tract infection that causes eustachian tube dysfunction.
• Common bacterial pathogens:
• — Streptococcus pneumoniae (most frequent).
• — Haemophilus influenzae (non-typeable).
• — Moraxella catarrhalis.
• Less common causes: Streptococcus pyogenes, Staphylococcus aureus.
• Viral causes (10–20%): Respiratory syncytial virus, rhinovirus, influenza virus, adenovirus.

Pathophysiology

• Viral infection or allergy leads to eustachian tube obstruction and negative middle ear pressure.
• This allows accumulation of secretions and secondary bacterial invasion.
• Inflammation causes mucosal edema, pus formation, and increased middle ear pressure.
• Tympanic membrane becomes bulging, erythematous, and immobile.
• If untreated, can lead to rupture of tympanic membrane and drainage of purulent material.