Optic neuropathy associated with periostitis in relapsing polychondritis.

Optic neuropathy is an uncommon manifestation of relapsing polychondritis (RPC), a rare systemic disease affecting cartilaginous and proteoglycan-rich structures. The optic neuropathy has been attributed to ischemia, intrinsic inflammation of the optic nerve, or spread of inflammation to the nerve from adjacent intraconal orbital tissues. We report a case of recurrent corticosteroid-responsive optic neuropathy in which MRI did not show ocular, optic nerve, or intraconal orbital abnormalities but did show periosteal thickening and enhancement in the apical orbit and adjacent intracranial space consistent with periostitis. The periostitis, which is a manifestation of a systemic vasculitis or an autoimmune reaction to progenitors of cartilage, probably caused the optic neuropathy by compression or inflammation. It is important to recognize this mechanism of optic neuropathy as its imaging features may be a subtle yet critical clue to an underlying systemic condition that can be life-threatening if not properly managed.