Contralateral Cavernous Sinus Thrombosis Caused by Sphenoid Sinusitis: Case Report and Literature Review.

Cavernous sinus thrombosis (CST) is a rare but life-threatening infectious disease whose diagnosis and treatment are challenging. CST can result in ocular and neurologic morbidities, as well as fatal systemic complications due to systemic thrombus. Occasionally, these clinical symptoms can be a result of contralateral sinusitis. A 75-year-old female presented with severe headache and fever. Magnetic resonance imaging revealed a multifocal filling defect in both cavernous sinuses, with heterogeneous enhancement and thrombosis of the right superior ophthalmic vein. Intravenous antibiotic was administered, and endoscopic sinus surgery was performed. The patient was discharged 40 days after admission and there were no neurologic symptoms and no evidence of sequelae during the 10-month follow-up. Symptoms of CST on the contralateral side are often missed, which delays initiation of appropriate treatment. When CST secondary to paranasal sinusitis is diagnosed, clinicians should consider contralateral as well as ipsilateral infection of the paranasal sinus. Preventing disease progression and complications through early and aggressive antibiotic administration along with sinus surgery is crucial.