Posttraumatic anosmia secondary to central nervous system injury.

Background: The presumed pathogenesis of posttraumatic anosmia is stretching or shearing of the olfactory nerves in a coup-contracoup head contusion. Direct injury to the brain is an alternate mechanism of injury. In this study we report a case where direct injury to the brain is the probable mechanism of injury.
Methods: A case report was performed.
Results: A 55-year-old man presented with loss of smell beginning 1 month after a closed head injury with loss of consciousness. The MRI showed posttraumatic scarring in the region of the olfactory bulbs.
Conclusion: This case suggests that central nervous system injury to the olfactory bulbs and tracts may be a mechanism of posttraumatic anosmia.