A carotid artery cavernous sinus fistula is a rare medical condition characterized by an abnormal connection between the carotid artery and the cavernous sinus. This can lead to a number of concerning symptoms, such as severe headache, eye redness or swelling, vision problems, and even potentially life-threatening complications. While the term "carotid artery cavernous sinus fistula" is specific and descriptive, there are also some synonymous terms used to refer to this condition. These include cranial dural arteriovenous fistula, cavernous sinus-carotid fistula, and cavernous-carotid sinus fistula. Though different names are used, they all refer to the same abnormality in blood vessel connections, highlighting the importance of early diagnosis and proper management.