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Table of Contents
Year : 2020  |  Volume : 25  |  Issue : 1  |  Page : 53-56

Incidental traumatic carotid cavernous fistula discovered only on conventional cerebral angiography: A case report

1 Department of Radiology, University of Benin, Benin City, Nigeria
2 Department of Radiology, Taoyuan General Hospital, Taoyuan City, Taiwan

Date of Submission11-Sep-2019
Date of Decision22-Dec-2019
Date of Acceptance18-Feb-2020
Date of Web Publication03-Apr-2020

Correspondence Address:
Dr. Festus O Ehigiamusoe
Department of Radiology, University of Benin, PMB 1154, Benin City, Edo State.
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmh.IJMH_28_19

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Carotid cavernous fistula (CCF) is not an uncommon occurrence in patients involved in road traffic accident with head injury. It involves an abnormal communication between the cavernous sinus and the carotid arteries presenting with clinical features. Its pathogenesis could be traumatic or spontaneous. Our patient was a 32-year-old woman involved in a road traffic accident with head injury. Emergency cranial computed tomography scan revealed subarachnoid hemorrhage and suspected aneurysm of the left internal carotid artery. Subsequent computed tomographic angiography and magnetic resonance angiography were negative for aneurysm or CCF, but a latter digital subtraction cerebral angiography showed florid signs of CCF (dilated cavernous sinus and left ophthalmic vein), though, no clinical features of CCF were observed in this patient. The patient was subsequently referred to another hospital with a neurointerventional radiologist for management. In conclusion, this case shows that the absence of clinical features and negative noninvasive imaging investigation does not exclude the diagnosis of CCF.

Keywords: Carotid cavernous fistula, computed tomographic scan, Magnetic resonance angiography, Conventional angiography

How to cite this article:
Ehigiamusoe FO, Lee MC. Incidental traumatic carotid cavernous fistula discovered only on conventional cerebral angiography: A case report. Int J Med Health Dev 2020;25:53-6

How to cite this URL:
Ehigiamusoe FO, Lee MC. Incidental traumatic carotid cavernous fistula discovered only on conventional cerebral angiography: A case report. Int J Med Health Dev [serial online] 2020 [cited 2020 Nov 29];25:53-6. Available from: https://www.ijmhdev.com/text.asp?2020/25/1/53/281885

  Introduction Top

Carotid cavernous fistula (CCF) is an abnormal connection between the carotid artery and the cavernous sinus. Any of the internal carotid arteries (ICAs) and external carotid arteries with their branches could be involved.[1] Hence, it is an arteriovenous connection, which could present with some attendant health challenges. It could be due to head trauma from road traffic accident, fall from height, or crush injury to the head, resulting in the fracture of the base of skull or could be spontaneous in individuals with preexisting aneurysm such as in atherosclerotic disease and connective tissue disease (Marfan syndrome, fibromuscular dysplasia, and Ehlers–Danlos disease).[1],[2],[3] Furthermore, Liang et al.[4] showed that base of skull fracture was responsible for 3.8% incidence of traumatic CCF. Some authors have also documented iatrogenic etiologies in the pathogenesis of some cases of CCF such as in rhinoplasty, orbital floor fracture reductions, partial maxillectomy, nasopharyngeal biopsy, and LeFort 1 osteotomy.[5] Nonetheless, idiopathic CCF has also been reported in the literature.[5]

Like other disease entities, CCF also presents with some clinical features, which include conjunctival congestion, proptosis, pulsating exophthalmos, diplopia, ophthalmoplegia, orbital pain, audible bruits, and blindness.[1],[6],[7] In a rare occurrence, Ko et al.[8] reported a life-threatening epistaxis as a symptom of CCF in a patient in South Korea. Most of these symptoms can also be found in some differential diagnoses of CCF, which include cavernous sinus thrombosis, cavernous sinus tumors, orbital tumors, arteriovenous malformation, orbital cellulitis, mucocele, and orbital vasculitis.[1] Invariably, this creates a diagnostic dilemma as these symptoms are not specific to CCF; hence, the diagnosis can be missed. It is pertinent to state that one must have a high index of suspicion in order not to miss the diagnosis.

Patients with CCF are most likely going to present to the ophthalmologist due to the ocular features. But its management, which undoubtedly, includes diagnosis, treatment, and follow-up will also involve the neuroradiologist and the neurosurgeon.

This index patient came with symptoms with no inkling to the possibility of a head injury coexisting with CCF. Subsequent cranial computed tomography (CT) scan and magnetic resonance imaging (MRI) only showed subarachnoid hemorrhage (SAH), but the CCF was only discovered on conventional angiography of the carotid arteries.

  Case Report Top

A 32-year-old woman was brought into the emergency room (ER) by 119 (ambulance service operated by emergency management service of Taiwan) with a history of loss of consciousness following a road traffic accident. On examination at the ER, she was found to be unconscious with a Glasgow Coma Scale (GCS) score of 7, right-sided limb weakness was noticed, but the pupils were reactive. Vital signs on presentation were blood pressure of 162/103mm Hg, temperature of 38.4°C, pulse rate of 100 beats/min, and respiratory rate of 13 cycles/min.

An emergency cranial CT scan showed features of SAH with suspected aneurysm of the left ICA at the carotid siphon [Figure 1]. Subsequently, a computed tomographic angiography (CTA) of the cerebral arteries was then requested but showed no feature of aneurysm apart from the SAH. A magnetic resonance angiography [Figure 2] carried out 3 days after admission also proved negative for aneurysm.
Figure 1: Cranial CT scan showing SAH and suspected left ICA aneurysm (white arrow)

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Figure 2: MRA showing normal circle of Willis

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The patient was then managed as a case of head injury with SAH, but no improvement was observed in her clinical status, which then informed the choice of conventional angiography on the sixth day of her admission. Angiography of both ICAs and vertebral arteries showed a left CCF with dilated superior ophthalmic vein and opacification of the contralateral cavernous sinus, sphenoparietal sinus, and the internal jugular vein [Figure 3]. A diagnosis of CCF was made. Though, the patient was still not fully conscious as at the time of the conventional angiography and ocular examination, she did not show any sign of proptosis or conjunctival ingestion of the left eye. The patient was subsequently referred to another hospital with a neuroradiologist for possible neurointerventional management as the referring hospital lacked a neurointerventionist. This case is being reported because the clinical symptoms were absent in the full glare of the radiological features of CCF.
Figure 3: DSA image of cerebral arteries showing engorged superior ophthalmic vein

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  Discussion Top

CCF is an abnormal communication between the carotid artery and the cavernous sinus, and this brings about arterialization of venous circulation, thereby increasing the venous pressure.[9] Invariably, this leads to reduced arterial flow and possible underperfusion of structures distal to the point of fistulous connection.[1] Anterior and posterior venous back pressure will result in engorgement of the superior ophthalmic vein and the petrosal sinus, respectively.[10] These changes bring about the symptoms and signs that are elicited in CCF.

The literature is replete with the different classification of CCF based on hemodynamics of blood flow (high or low), etiology (traumatic or spontaneous), and angiographic anatomy (direct or indirect).[9],[10],[11] However, Barrow et al.,[12] in 1985, propounded a mode of classification, which is all-encompassing and it is still valid till date. Four types, that is, A, B, C, and D are entertained by this classification, where type A CCF is due to direct communication between the ICA and the cavernous sinus. Explicitly, type B fistula is communication between branches of ICA and cavernous sinus, type C fistula is communication between branches of external carotid artery and cavernous sinus, whereas type D fistula results from communication between dural branches of ICA and external carotid artery branches and the cavernous sinus.

The most often encountered CCF is the type A, which is also described as a direct type, and trauma is said to be the most common causative agent, accounting for approximately 75% of cases.[13] It could be bilateral or unilateral; bilateral cases are observed in 1%–2% of traumatic CCF.[13],[14] The index case resulted from road traffic accident and had a left-sided unilateral CCF though with opacification of both external jugular veins. Occasionally, some connective tissue diseases such as Ehlers–Danlos syndrome and fibromuscular dysplasia can predispose to spontaneous type A CCFs.[2] Iatrogenic causes, such as endovascular procedures and transsphenoidal surgeries, have also been implicated in type A direct CCFs.[15] Traumatic type A CCFs occur more in young male patients, whereas spontaneous CCFs are observed in elderly female patients.[14] However, our patient being reviewed is a young female, which is not congruent with the aforementioned literature documentation. The other types under Barrow’s classification are said to be indirect and often of low velocity.[2],[15] There was absence of symptoms, suggestive of CCF in our patient. The symptoms may not have also been noticed as she was unconscious while on admission in our hospital before her referral to another health facility. Direct CCF is known to present with sudden onset of chemosis, proptosis, and bruit with the degree of presentation depending on the pressure built up within the arterialized cavernous sinus.[2] The venous pressure may not have built up in our patient to the degree of causing obvious symptoms, another probable reason for the observation about the clinical findings.

Any case of suspected CCF needs to be confirmed by radiological imaging as there are lots of differential diagnoses of this disease entity. Invariably, the noninvasive imaging modalities, such as CT scan and CTA, MRI, and MRA, are usually first-line investigative methods. These may show enlarged cavernous sinus, superior ophthalmic vein engorgement, proptosis, and enlargement of extraocular muscles as well as skull fractures. However, the absence of abnormalities on noninvasive imaging studies does not exclude the diagnosis of CCF.[14] Invasive conventional cerebral angiography with digital subtraction is considered the gold standard imaging modality for the diagnosis of CCF.[5],[7],[14] Our patient had a direct type A CCF, which probably started as a traumatic aneurysm of the left ICA, suspected on the initial emergency cranial CT scan carried out. Perhaps, this aneurysm ruptured and led to the CCF. Hence, the aneurysm was not observed on the CTA and MRA, which were subsequently carried out. The features of CCF were also not found on the CTA and MRA but only visible on the conventional cerebral angiography. This observation is in tandem with the literature.

The goal of treating CCF is to occlude the fistula and maintain normal flow of blood through the ICA and cavernous sinus.[2],[14] Digital subtraction angiography of the cerebral arteries plays double role in CCF as it is used for both diagnosis and intervention. Transarterial or transvenous endovascular embolization is the first-line treatment of choice for most CCFs, wherein balloons and coils are used to close the fistulous connection.[14] This treatment modality is mainly for the type A CCFs. Transarterial route is used when branches of external carotid arteries are involved. But when ICA is involved, the transvenous route is used to obviate the possibility of stroke, resulting from embolic influx into ICA.[14] On the contrary, Marín-Fernández et al.[5] reviewed many literature and concluded that transarterial approach is most effective for direct CCFs, whereas transvenous approach is more effective for indirect CCFs. Conservative management, which involves manual compression of the involved ICA and the contralateral jugular vein several times a day over some weeks, has been documented to achieve cure in approximately 30% of low-flow indirect CCFs.[2] The index patient was referred to another health facility where a neuroradiologist was available for interventions.

In conclusion, the absence of symptoms does not exclude the possibility of CCF, and negative noninvasive investigations, such as CTA and MRA, also do not exclude its diagnosis.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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Çelik GK, Yildirim E. Epileptic seizures induced by a spontaneous carotid cavernous fistula. Case Rep Med 2016;2016:9396014.  Back to cited text no. 3
Liang W, Xiaofeng Y, Weiguo L, Wusi Q, Gang S, Xuesheng Z. Traumatic carotid cavernous fistula accompanying basilar skull fracture: A study on the incidence of traumatic carotid cavernous fistula in the patients with basilar skull fracture and the prognostic analysis about traumatic carotid cavernous fistula. J Trauma 2007;63:1014-20.  Back to cited text no. 4
Marín-Fernández A, Cariati P, Román-Ramos M, Fernandez-Solis J, Martínez-Lara I. Posttraumatic carotid-cavernous fistula: Pathogenetic mechanisms, diagnostic management and proper treatment. A case report. J Clin Exp Dent2016;8:e226-9.  Back to cited text no. 5
Stanton DC, Kempers KG, Hendler BH, Cutilli BJ, Hurst RW. Posttraumatic carotid-cavernous sinus fistula. J Craniomaxillofac Trauma 1999;5:39-44.  Back to cited text no. 6
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Ko JK, Lee SW, Lee TH, Choi CH. Traumatic carotid cavernous fistula with a connection between the supraclinoid internal carotid artery and cavernous sinus via a pseudoaneurysm presenting with delayed life-threatening epistaxis. NMC Case Rep J 2017;4:43-6.  Back to cited text no. 8
Carotid-cavernous fistula(CCF). Available from: https://emedicine.medscape.com/article/1217766-overview. [Last accessed on 2018 Feb 12].  Back to cited text no. 9
Rucker JC, Biousse V, Newman NJ. Magnetic resonance angiography source images in carotid cavernous fistulas. Br J Ophthalmol 2004;88:311.  Back to cited text no. 10
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Barrow DL, Spector RH, Braun IF, Landman JA, Tindall SC, Tindall GT. Classification and treatment of spontaneous carotid-cavernous sinus fistulas. J Neurosurg 1985;62:248-56.  Back to cited text no. 12
Yoo K, Krisht AF. Aetiology and classification of cavernous carotid fistulas. In: Eisenberg MB, Al-Mefty O, editors. The cavernous sinus: A comprehensive text Philadelphia, PA: Lippincott Williams & Wilkins; 2000. pp. 191-200.  Back to cited text no. 13
Ellis JA, Goldstein H, Connolly E Jr, Meyers PM. Carotid-cavernous fistulas. Neurosurg Focus 2012;32:E9.  Back to cited text no. 14
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  [Figure 1], [Figure 2], [Figure 3]


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