Bilateral Carotid-Cavernous Fistula Following Traumatic Fall: A Case Report

Carotid-cavernous fistulas (CCFs) are abnormal connections between the carotid arteries and the cavernous sinus, posing significant neuro-ophthalmologic risks. This report presents a rare case of bilateral post-traumatic CCFs, focusing on clinical presentation, diagnosis, and management. Symptoms mimic conjunctivitis, causing diplopia, exophthalmos, and ophthalmoplegia. Diagnosis relied on computed tomography, magnetic resonance angiography, and digital subtraction angiography. Management involved transarterial embolization with coils, achieving successful outcomes. This highlights the importance of timely intervention and comprehensive imaging to prevent complications. Teaching point: This case report details a rare instance of bilateral post-traumatic carotid-cavernous fistulas, emphasizing clinical presentation, diagnostic evaluation, and management.


INTRODUCTION
Carotid-cavernous fistulas (CCFs) are abnormal connections between the carotid artery and the cavernous sinus, causing severe neuro-ophthalmologic complications like vision loss, cranial nerve palsies, and intracranial hemorrhage.They are classified as direct, typically from trauma, or indirect, often linked to aneurysms or connective tissue disorders [1,2].Bilateral CCFs are rare and usually traumatic, leading to symptoms like exophthalmos, chemosis, and cranial nerve deficits [3,4].
Prompt diagnosis and management are vital.Advanced imaging techniques, such as multidetector computed tomography (CT) and magnetic resonance (MR) angiography, are crucial for classification and treatment planning, while digital subtraction angiography (DSA) remains the gold standard [5,6].Modern management involves endovascular techniques like transarterial and transvenous embolization using coils, balloons, and liquid embolics, which have high success rates [7,8].
This case report presents a rare instance of bilateral post-traumatic CCFs, emphasizing the importance of advanced imaging techniques, particularly MR imaging (MRI) and DSA, in timely identification and management.

CASE REPORT
A 64-year-old woman fell, resulting in lip numbness and difficulty closing her mouth.CT showed a bifocal mandibular fracture and a left C1 fracture (Figs.1-3), without intracranial bleeding, treated surgically.Three weeks later, she developed right eye redness, swelling, and tearing, initially misdiagnosed as conjunctivitis.Bilateral diplopia and VI nerve paresis, primarily on the right, followed.CT showed grade 1 exophthalmos of the left eye without fracture.
Post-contrast brain CT revealed enlarged intracavernous portions of the internal carotid arteries, dilated cavernous sinuses, and superior ophthalmic veins (Figs. 4 and 5), indicating a CCF and signs of dissection sequelae (Fig. 6).
DSA was used for planning treatment.Percutaneous transarterial embolization with coils was performed.Sixteen coils nearly occluded the fistula, leaving a slight shunt (Fig. 11).

DISCUSSION
Bilateral CCFs are rare and complex.In this case, trauma caused tears in the internal carotid artery, leading to conjunctivitis-like symptoms with diplopia and ophthalmoplegia.These symptoms result from increased venous pressure and arterialization of conjunctival vessels, causing redness, swelling, and hyperemia [9].
The use of CT and MR angiography identified bilateral CCFs with venous dilation and arterialized flow in the superior ophthalmic veins and cavernous sinuses.MR images also showed edema, hemorrhagic changes, and venous infarctions.CCFs can cause significant vascular complications, including hemorrhages and infarctions, due to arterial blood entering the venous system, leading to venous hypertension, vessel wall weakening, and potential rupture.Additionally, venous congestion can impair drainage, causing ischemia and infarctions [2,9].
DSA was essential for planning endovascular treatment.Percutaneous transarterial embolization, typically with detachable balloons or platinum coils, is the preferred approach.In this case, DSA guided the embolization with coils, proving invaluable for mapping the fistula and assessing the procedure's success [2,9].
Successful outcomes included complete CCF occlusion and regression of venous dilation and edema.However, a minimal residual shunt necessitates ongoing monitoring to prevent complication.
The complexity and rarity of bilateral CCFs demand expertise in imaging for accurate diagnosis and management.Future research should refine diagnostic   This case also demonstrated that the management of CCFs involves a multidisciplinary approach, requiring collaboration among neurologists, ophthalmologists, radiologists, and interventional neuroradiologists.

CONCLUSION
This case emphasizes the difficulties in diagnosing and treating bilateral CCFs, a rare and complex condition.Advanced imaging and targeted embolization were effective, leading to significant symptom improvement.However, the presence of a minimal residual shunt highlights the need for long-term follow-up.The successful outcome highlights the importance of a multidisciplinary approach for comprehensive care and improved patient outcomes.

Figure 1
Figure 1 Axial CT scan showing a bifocal mandibular fracture with displacement.

Figure 2
Figure 2 3D CT reconstruction showing a bifocal mandibular fracture with displacement.

Figure 3
Figure 3 Axial CT scan (bone window) showing a non-displaced fracture of the left anterior arch of the C1 vertebra.

Figure 4
Figure 4 CT angiography showing early opacification of the cavernous sinuses.

Figure 5
Figure 5 CT angiography showing dilatation of the superior ophthalmic veins.

Figure 6
Figure 6 CT angiography showing sequelae of dissection in the cervical portion of the bilateral internal carotid arteries, with an intimal flap indicated by an arrow.

Figure 7
Figure 7 MR angiography showing dilatation of the superior ophthalmic veins.

Figure 8
Figure 8 MR angiography showing a fistula between the cavernous sinus and the cavernous portion of the carotid artery.

Figure 9 Figure 10
Figure 9 Axial T2 and post-contrast T1 weighted images showing dilatation of the leptomeningeal veins in the left cerebellar hemisphere, indicating abnormal venous drainage.

Figure 11
Figure 11 Pre-treatment Digital Subtraction Angiography (DSA) showing bilateral carotid-cavernous fistulas (CCFs), followed by post-treatment images demonstrating successful occlusion of the CCF.

Figure 12
Figure12MR Angiography showing the presence of a residual fistula following treatment.

Figure 13
Figure 13 MRI images showing regression of edema in the right pontine region and persistent dilation of the cerebellar veins, indicating partial resolution of the condition.

Figure 14
Figure 14 Digital Subtraction Angiography showing complete obliteration of the carotid-cavernous fistula (CCF), indicating successful treatment.