Acute otitis media (AOM) is an acute, suppurative infectious process marked by the presence of infected middle ear fluid and inflammation of the mucosa lining the middle ear space. The infection is most frequently precipitated by impaired function of the Eustachian tube, resulting in the retention and suppuration of retained secretions. AOM may also be associated with purulent otorrhea if there is a ruptured tympanic membrane. AOM usually responds promptly to antimicrobial therapy.
Microbiology
Common bacteria causing AOM in both children and adults are Streptococcus pneumoniae and Haemophilus influenzae. Group A Streptococcus, Staphylococcus aureus, and Moraxella catarrhalis are less frequent causes.
Pathogenesis of AOM in adults
Eustachian tube dysfunction, commonly related to seasonal allergic rhinitis or upper respiratory tract infection, is the most important factor in the pathogenesis of middle ear infections in adults.
Clinical presentation and diagnosis
AOM is typically associated with the development of unilateral otalgia and decreased hearing. Otoscopy is required for accurate diagnosis; the addition of pneumatic otoscopy, if available, is helpful in providing additional diagnostic information. The tympanic membrane in AOM is bulging, opacified, immobile, and often erythematous. On physical examination (or audiometry if available), a conductive hearing loss may be demonstrated.
