R. NICKBRYANMDS. JAMESZINREICHMD
Labyrinthitis ossificans is the pathologic ossification of spaces in the membranous labyrinth that occurs in response to a destructive process.1 Inflammation usually occurs in the perilymphatic spaces, typically sparing the endolymphatic space.2 As early as 2 weeks after the onset of meningitis, fibrosis is present, followed by new bone formation, which may be seen within 2 months.2 While ossification is accompanied by degenerative changes in the stria vascularis and organ of Corti,1 the auditory nerve fibers are retained to a variable degree.3 Labyrinthitis ossificans has several possible causes, including trauma, otosclerosis, and viral infection; the most common cause is bacterial infection of the inner ear resulting in suppurative labyrinthitis. Infection may reach the inner ear by 3 routes: the middle ear, the meninges, or (rarely) hematogenous dissemination.1 Ossification initially develops in the basal turn of the cochlea. In the case of middle ear disease, infection is believed to reach the inner ear via the round window, while with acute bacterial meningitis, infection travels from the subarachnoid space to the scala tympani through the cochlear aqueduct or the internal auditory canal.4
Quiz Case 1. Arch Otolaryngol Head Neck Surg. 1999;125(8):914–915. doi:
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