Aggravation of Fistula between a Posterior Communicating Artery Aneurysm and the Cavernous Sinus Symptoms after Neurosurgical Clipping and Embolization: A Case Report

Purpose: Fistula between a posterior communicating artery aneurysm and the cavernous sinus is very rare and few cases have been reported in the literature so far. Methods: We report two patients including a 51-year-old man and a 43-year-old woman, who were known cases of treated fistula between a posterior communicating artery aneurysm and the cavernous sinus via neurosurgical clipping and embolization, who presented with decreased vision, eye proptosis, conjunctival chemosis and dilated episcleral vessels. Results: Further evaluation demonstrated that the patients had elevated intraocular pressure with a shallow anterior chamber.Fundus examination and imaging studies including optical coherence tomography and fluorescein angiography revealed choroidal effusion with retinal nerve fiber layer changes. Based on their history and imaging studies a diagnosis of secondary choroidal effusion with angle closure glaucoma and venous stasis retinopathy was made, and patients were treated with anti-glaucoma medications including eye drops of timolol, brimonidine, oral medication with acetazolamide and peripheral iridotomy in the affected eye. Conclusion: In all patients with an internal carotid artery (or its branches) and cavernous sinus fistula, even in treated patients close ophthalmic follow-up visits must be done to reduce the risk of vision threatening side conditions like choroidal effusion and secondary angle closure glaucoma.