Otitis media: pathogenesis and medical sequelae

Eustachian tube abnormalities are a primary determinant of otitis media. Other determinants include viral infections and local and systemic immune deficiencies, which predispose to superimposed bacterial disease. Local infection induces inflammation, which can be exacerbated by the presence of antibiotics. The degree of inflammation determines the extent of damage and the oedema and histological damage correlate with the white blood cell count and not the bacterial count. Local sequelae include recurrent or persistent acute otitis media, recurrent or chronic otitis media with effusion and chronic suppurative otitis media. Other local sequelae include occasional perforation of the tympanic membrane, sensorineural hearing loss, acute serous labyrinthitis, and facial palsy, which can occur associated with the course of the facial nerve across the middle ear. Acute otitis media can lead to persistent loss of a significant amount of sensorineural hearing after treatment and resolution of the effusion. Damage is usually very mild or nonexistent in the speech frequency ranges, but detectable if high frequency audiometry is performed. Studies in otitis media with effusion have shown a mild association between its presence and speech and language development in children under the age of 4 years. But also in older children, there is a continued association between otitis media with effusion, affecting expressive language development, reading skills and behavior. Therefore physicians have a major responsibility in managing otitis media.