A novel etiology for pneumolabyrinth after temporal bone fracture without otic capsule involvement.

Pneumolabyrinth has been considered an indicator of otic capsule involvement in temporal bone fractures. We present a novel theory for the etiology of pneumolabyrinth in a trauma patient without an otic capsule fracture: passage of intrathecal air into the labyrinth. Our patient experienced transient bilateral pneumolabyrinth after head trauma due to a motor vehicle collision. The patient was noted to have extensive pneumocephalus and a unilateral temporal bone fracture that spared the otic capsule. Initial computed tomography (CT) scans demonstrated air in the cochlea and both internal auditory canals. A high-resolution CT scan 6 hours later showed resolution of this air. Pneumolabyrinth may not be a sensitive indicator of otic capsule involvement in temporal bone fractures. In addition to middle ear sources, air in the labyrinth can also plausibly originate intrathecally, especially in the setting of pneumocephalus.