| Print Date: | June 19, 2013, 9:44 am |
| Title | 1. Traumatic carotid-cavernous fistula (direct, high-flow) 2. Longitudinal (left) temporal bone and clivus fractures. |
| Text | Rupture of the internal carotid artery (ICA) or one of its branches into the cavernous sinus produces a fistulous connection between the high pressure arterial system and the lower pressure venous system (carotid-cavernous fistula {CCF}). CCF can be classified in several fashions: direct or indirect; traumatic or spontaneous; and high-flow or low-flow. Direct fistulae are due to rupture of the ICA itself into the cavernous sinus. They are usually high flow and found in young adults following trauma. Occasionally, direct CCF arise from intracavernous rupture of an ICA weakened by predisposing vascular lesions (aneurysms, fibromuscular disease, collagen vascular disease). Indirect fistulae are due to rupture of small intracavernous branches of the internal or external carotid arteries into the cavernous sinus. Indirect CCFs are usually low flow and are more commonly encountered in postmenopausal females.
Presenting symptoms of CCF vary greatly, depending on the size of the arteriovenous shunt and the pattern of venous drainage. Symptoms may be minimal with small, spontaneous, low-flow CCF. Large direct, high-flow fistula with predominant anterior venous drainage, however, may have quite dramatic symptoms. High-flow lesions produce arterialization of the cavernous sinus and marked elevation of the venous pressures. Symptoms can be due to; 1. elevated venous pressure and venous distension; 2. cerebrovascular "steal" from severe shunting through the arteriovenous fistula; 3. hemorrhagic phenomenon from rupture of the arterialized thin-wall veins; and 4. thromboembolic events. Common presenting symptoms of high-flow CCF include; subjective bruit (75%), proptosis (69%), conjunctival swelling and chemosis (36%), diplopia (24%), blurred vision (16%), and orbital pain (16%). Progressive monocular or bitemporal visual loss are also quite common. Epistaxis, intracerebral hemorrhage, otorrhagia, cerebral edema, and TIAs are less frequent symptoms. Although symptoms are greatly affected by the size of the shunt, they are also influenced by the pattern of venous drainage. Anterior drainage, through the superior and inferior ophthalmic veins into the angular and facial branches of the external jugular vein, is the most common pattern. Orbital and visual symptoms typically predominate with this pattern. Orbital symptoms are usually unilateral and ipsilateral to the side of the CCF. Contralateral symptoms may develop, however, if there is brisk fill of the contralateral cavernous sinus and ophthalmic veins. Since the cavernous sinuses are normally connected across the midline via the circular dural sinus, contralateral or even bilateral symptoms are to be expected. The predominate drainage will be posterior, on occasions, into the inferior and superior petrosal sinuses and internal jugular veins. Orbital symptoms may be less pronounced in these situations. Other potential drainage pathways are: 1. laterally, into the sphenoparietal sinus; 2. inferiorly, into the pterygoid plexus of veins; and 3. centrally, into cortical veins. |
| References: | |
| Contributor | Neuroradiology Learning File - © ACR (ACR Learning File®) |
| Author | Lindell R. Gentry, MD |
| Peer Reviewer | James G. Smirniotopoulos, M.D. (Uniformed Services University) |
| Record Number | : 1553 |
| Created | 2001-03-27 14:42:09-05 |
| Modified | 2001-08-07 22:15:44-04 |
| Category: | Trauma |
| Location: | Brain and Neuro |
| Sublocation: | None Selected |
| MedPix® Medical Image Database Content Text and Images may be Copyright © 1999 - 2006 by the Original Contributors | |