Cavernous Carotid Aneurysm Presenting as Direct Carotid-Cavernous Fistula with Contralateral Ocular Symptoms: A Rare Case Report

Abstract

ABSTRACT Carotid-cavernous fistula (CCF) resulting from intracavernous carotid artery aneurysms is uncommon. However, if rupture does occur, it can lead to a CCF, which causes sudden onset of unilateral ophthalmoplegia. In this report, we present a case of a ruptured giant intracavernous carotid artery aneurysm leading to a direct CCF with contralateral ocular features. The aim is to discuss the distinctiveness of this case and the most challenging aspects of identifying similar cases. A woman in her sixties developed a sudden direct CCF, resulting in proptosis in the opposite eye. Magnetic resonance angiography revealed that the left cavernous sinus (CS) and superior ophthalmic vein were dilated, whereas the right side was unaffected. However, digital subtraction angiography (DSA) revealed a large aneurysm in the right cavernous internal carotid artery (ICA) and a direct connection between the right ICA and CS, with venous drainage exclusively occurring in the opposite direction via the intercavernous sinus. To address the issue, the aneurysm and fistula underwent Coil and Onyx embolisation, successfully closing the fistula and leading to a regression in the orbital symptom. This presents a unique scenario of an unexpected unilateral CCF with contralateral symptoms in a direct CCF, which demands immediate attention. It is crucial to remain alert for CCF and verify the diagnosis through DSA when dealing with such patients to avoid severe outcomes. Prompt identification and intervention can enhance the patient’s chances of a positive outcome.