Carotid-cavernous Fistula

carotid-cavernous fistula

A carotid-cavernous fistula is an abnormal connection that forms between the carotid artery and the cavernous sinus, a vein-filled space at the base of the skull. This connection lets high-pressure arterial blood flow directly into the low-pressure venous system around the eye and nearby nerves. The result can be increased pressure in the veins of the eye, swelling, redness, and problems with eye movement and vision. People may notice a bulging eye, a noisy whooshing sound in the head or ear, double vision, or a sudden rise in eye pressure. It can develop after head trauma, from a ruptured blood vessel, or from weakening of the arteries with age. Doctors diagnose it using imaging tests such as CT or MRI and special X-ray studies of the blood vessels called angiography. Treatment most often involves a minimally invasive procedure in which a specialist blocks the abnormal connection from inside the blood vessels. If left untreated, the condition can damage the eye, cause permanent vision loss, or lead to bleeding or other serious complications, so prompt recognition and treatment matter. After treatment many people improve, but follow-up is needed to monitor eye pressure and nerve function.