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Purulent otitis media is grossly
characterized by a thin cloudy effusion.
Histologically, the sub-epithelial space appears edematous and
filled with inflammatory cells, mainly polymorphonuclear leukocytes, and
the epithelial layer is often denuded (Figure 1). The
etiology is bacterial infection, generally via the Eustachian tube
however, purulent otitis media can also result from systemic infection.
Toxic substances (bacteria,
bacterial toxins, pharmacologics, etc.) can pass through the round
window membrane and into the inner ear causing labyrinthitis and
sensorineural hearing loss. Inflammatory
cells also have the potential to enter the internal auditory canal and
cause tympanogenic meningitis.
Figure 1. This 3
month old male had Hemophilus influenzae meningitis. Purulent otitis
media (POM) is seen behind a thickened, intact tympanic membrane (TM).
The external canal is filled with cerumen.
The middle ear mucosa (MEM) is polypoidal with numerous
inflammatory cells.
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