Figure 1: CT axial (A) demonstrated a focal inflammatory process in the posterior sphenoid sinus on the left with developmental dehiscence of the lateral wall of the optic nerve canal (arrow), allowing the inflammatory process to extend into the apex of the orbit. MR contrast-enhanced images: Axial image (B) reveals enhancement of the inflammatory process extending from the posterior sphenoid sinus into the orbital apex and around the optic nerve (arrow). Inflammation of the medical rectus muscle and periorbital area is also noted at this level. Coronal image (C) at the level of the orbital apex (arrow) and a coronal image (D) at the level of the proximal optic nerve (arrow) showing perineural inflammatory enchancement.
ary to direct compression by the expansive inflammatory lesion or to ischemic infarction from thrombophlebitis or vasculitis. 2,6 Early diagnosis and surgical intervention are essential to prevent permanent blindness, which may ensue within one to two hours. 2 Our case emphasizes the significance of anatomical variations, particularly bony dehiscence over the optic canal. These defects are rare but predict a poor prognosis. Lower thresholds for diagnosis and interven-
tion must be taken with immunocompromised patients because of the increased likelihood of severe progressive infection causing erosive dehiscence alongside other com- plications and even death. 2,6 If acute sphenoid sinusitis is suspected, broad spectrum IV antibiotics should be initi- ated, a detailed cranial nerve exam should be performed, and CT imaging of the orbit, paranasal sinuses, and skull base obtained. Irreversible damage to the optic nerve can occur before development of gross intraorbital pathology.
J La State Med Soc VOL 166 March/April 2014 71
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