Journal of the Louisiana State Medical Society
Sphenoid Sinus Dehiscence as a Risk For Visual Consequences in an Immunocompromised Patient
Crystal P. Le, BS; Alejandra A. Valenzuela, MD; Michael Rosenberg, MS; Laveil Allen, MD; Enrique Palacios, MD, FACR
Isolated sphenoid sinus disease is a rare entity with severe and potentially life threatening sequela. Because of the proximity of the sinus to the orbit, anatomical defects within the surrounding bony structures can fa- cilitate communication with orbital content, predisposing the patient to substantial visual consequences. We report a case of a 51-year-old immunocompromisedmale who presentedwith headache and gradual unilateral decreases in vision. Computed tomography revealed opacification of the left sphenoid sinus accompanied by unusual bony dehiscence of the proximal optic canal. Early recognition and treatment of sphenoid sinusitis requires urgent surgical intervention with delay of treatment potentially leading to irreversible blindness or other devastating consequences. Bony dehiscence of the sphenoid sinus overlying the optic nerve has only been found in 4% of cadavers. It is associated with increased risk of orbital complications and predicts a poor prognosis. Immediate intervention is particularly important in immunocompromised individuals who are at greater risk of these severe complications.
INTRODUCTION Isolated sphenoid sinusitis is an uncommon condi- tion that comprises less than 3% of all cases of sinusitis. 2 The sphenoid sinus is intimately juxtaposed near cranial nerves II-VI. An anomalous ostium increases the risk for disease complications due to the sinus’s inability to contain any swelling. Additionally, bony dehiscence of the sinus overlying the optic nerve has been found in 4% of cadavers. These variations increase the risk of orbital complications secondary to the lack of a barrier to prevent spread of infec- tion. 2 The incidence of permanent vision loss in these cases is as high as 10.5%, thereby requiring a prompt diagnosis. Immunocompromised individuals require immediate inter- vention due to the greater risk of severe infection causing bony dehiscence and other complications. 3 CASE REPORT A 51-year-old immunosuppressedmale presentedwith a three-month history of frontal headache with gradual vi- sion loss in the left eye. Examination revealed significant left periocular swelling, relative afferent pupillary defect, chemosis, extraocular movement limitation, and no light perception in the left globe. Orbital Computed Tomography (CT) (Figure 1, A) demonstrated inflammatory opacification of the left sphe-
noid sinus and unusual bony dehiscence at the proximal optic canal. Magnetic Resonance Imaging (MR) (Figure 1, B) revealed mild left proptosis with diffuse inflammatory enhancement of the intraconal fat and optic nerve sheath spanning mid orbit to apex. The coronal sections confirmed perineural inflammatory process of the optic nerve. Urgent functional endoscopic sinus surgery with left sphenoidectomy and sinus drainage was performed, and the patient improved within 24 hours. Subsequently, the patient’s condition declined over the next few days, and he expired after developing an acute ischemic infarction in the left basal ganglia with ophthalmoplegia and left cavernous sinus thrombosis. DISCUSSION Acute sphenoid sinusitis is an uncommon condition that is often misdiagnosed in the evaluation of refractory headache with visual changes. 1,2 Anatomical variances of the sphenoid sinus increase the risk of orbital complications. Accessory septa may modify the sinus drainage in 30% of cases. Bony dehiscence of the sphenoid sinus over the optic canal occurs in 4%-13% of cases. 1,2,5 The bony covering of the optic canal within the sphenoid sinus may be congenitally dehiscent or secondary to an erosive inflammatory process. Dehiscence of this bony structure permits exposure of the optic nerve, allowing irreversible nerve ischemia second-
70 J La State Med Soc VOL 166 March/April 2014
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