Bilateral carotid cavernous sinus fistula: a case report and review of the literature

Abstract

Carotid cavernous fistula (CCF) is an abnormal vascular shunt from the carotid artery to the cavernous sinus. They are commonly classified based on hemodynamics, etiology or anatomically. Hemodynamic classification refers to whether the fistula is high or low flow. Etiology is commonly secondary to trauma or can occur spontaneously in the setting of aneurysm or medical conditions predisposing to arterial wall defects. Bilateral carotid cavernous fistulas are rare. We present a case of bilateral CCF secondary to trauma. Ophthalmology was urgently consulted to assess the patient in the intensive care unit (ICU) for red eye. The patient was found to have decreased vision, increased intraocular pressure, an afferent pupillary defect, proptosis, chemosis, and ophthalmoplegia. Subsequent neuro-imaging confirmed a bilateral CCF. The patient underwent two endovascular embolization procedures. Trauma is the most common cause of CCF and accounts for up to 75% of cases. Most common signs of CCF depend on whether it is high or low flow. High-flow CCF may present with chemosis, proptosis, cranial nerve palsy, increased intraocular pressure, diplopia, and decreased vision. Cerebral angiography is the gold standard diagnostic modality. First-line treatment consists of endovascular embolization with either a metallic coil, endovascular balloon or embolic agent. It is unclear in the literature if bilateral cases are more difficult to treat or have a different prognosis. Our patient required two endovascular procedures suggesting that endovascular intervention may have reduced efficacy in bilateral cases.

Dural carotid cavernous fistula following hypertensive emergency

“…CCFs can be classified based on haemodynamics (high flow vs low flow), anatomy (direct vs indirect/dural) or aetiology (traumatic vs spontaneous). Previous reports have identified that greater than 75% of all CCFs are secondary to trauma 2–4. The mechanism is thought to be due to shear forces, or by direct damage sustained from bony injuries.…”

“…Conversely, dural CCFs arise secondary to systemic diseases including hypertension, Ehlers-Danlos, fibromuscular dysplasia and pseudoxanthoma elasticum 5 6. The Barrow classification system further organises CCFs into four types based on angiographic features: type A CCFs are the most common and present as direct, high-flow communications between the internal carotid artery (ICA) and cavernous sinus1 2; type B, C and D dural CCFs are characterised as indirect and low-flow communications. Dural CCFs occur when connections are formed between the cavernous sinus and smaller arterial branches of the internal or ECA.…”

“…Symptoms associated with CCFs include blurred vision, headache, tearing, diplopia or an audible bruit described as a ‘whooshing’ noise 1 2 4. The manner of presenting signs, however, depends on whether it is a direct or indirect fistula.…”

“…Transvenous approaches can also be employed in the management of CCFs and have shown high success rates, since this method avoids navigation through arterial feeder vessels and instead occludes the fistula from a more approachable pathway via the venous system 9 14. It is currently unknown whether the response to treatment is equivocal between unilateral and bilateral CCFs,2 although a stepwise approach has been advocated for the latter in order to reduce the risk of haemorrhagic reperfusion 9. A diagnosis of CCF should be made clinically, and in conjunction with a referral to interventional neuroradiology for diagnostic imaging and treatment if necessary.…”

“…Carotid-cavernous fistula (CCF) occurs in the presence of abnormal vascular connections between the internal or external carotid arteries (ECAs) and branches and the cavernous sinus 1. These vascular shunts are commonly secondary to trauma, but can also present spontaneously in the setting of systemic disease that results in damage to arterial walls 2 3. Herein, we present the first known case of a dural CCF following an episode of hypertensive emergency.…”