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Year : 2022  |  Volume : 2  |  Issue : 1  |  Page : 232-234

A rare case of nontraumatic bilateral carotid cavernous fistula Barrow type D – A case report

Department of Neuroophthalmology and Orbit and Oculoplasty, Aravind Eye Hospital, Madurai, Tamil Nadu, India

Date of Submission04-Jun-2021
Date of Acceptance17-Aug-2021
Date of Web Publication07-Jan-2022

Correspondence Address:
Dr. Maheshkumar Shanmugam
Department of Neuroophthalmology, Aravind Eye Hospital, 1, Kuruvikaran Salai, Annanagar, Sathamangalam, Madurai - 625 020, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1562_21

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Carotid cavernous fistula (CCF) is an abnormal communication between the cavernous sinus and the normal carotid arterial system. We are presenting a very rare case of spontaneous nontraumatic bilateral Barrow type D CCF. A 41-year-old patient presented to our tertiary eye care center with a history of long-standing bilateral congested eyes. On imaging, the patient was diagnosed with spontaneous bilateral Barrow type D CCF. The patient improved significantly by treatment with carotid decompression exercises. It is recommended to consider the diagnosis of bilateral CCFs as a differential diagnosis in patients with long-standing history of congested eyes nonresponsive to conventional topical treatment.

Keywords: Barrow classification, bilateral, carotid cavernous fistula, case report, nontraumatic

How to cite this article:
Shah L, Shanmugam M, Shah H, Kowsalya A, Narayanamoorthy JK. A rare case of nontraumatic bilateral carotid cavernous fistula Barrow type D – A case report. Indian J Ophthalmol Case Rep 2022;2:232-4

How to cite this URL:
Shah L, Shanmugam M, Shah H, Kowsalya A, Narayanamoorthy JK. A rare case of nontraumatic bilateral carotid cavernous fistula Barrow type D – A case report. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2022 Aug 14];2:232-4. Available from: https://www.ijoreports.in/text.asp?2022/2/1/232/334889

Carotid cavernous fistula (CCF) represents abnormal communication between the carotid arteries and the cavernous sinus. Direct fistulae are high-flow shunts in which carotid artery blood passes directly into the cavernous sinus through a defect in the wall of the intracavernous portion of the internal carotid artery. In an indirect fistula, the arterial blood flows through the meningeal branches of the external or internal carotid arteries indirectly into the cavernous sinus.[1] CCFs are most commonly unilateral, but bilateral have also been reported. We are reporting a rare case of CCF that was misdiagnosed as conjunctivitis and was later diagnosed radiologically as bilateral spontaneous indirect CCF.

  Case Report Top

A 41-year-old woman presented to our facility with complaints of bilateral red eyes and irritation for about 4 months. She was diagnosed and treated presumptively as conjunctivitis elsewhere, which was found to be nonresponsive to ofloxacin 0.3% and fluorometholone 0.1% eye drops. She had no complaints registered otherwise. There was no significant past ocular history. Her medical history was unremarkable. There was no history of head or eye trauma.

On examination, she had best-corrected visual acuity of 20/30 in the right eye and 20/20 in the left eye. On slit-lamp examination, there were tortuous, prominently diffused, corkscrew-shaped, and engorged scleral blood vessels seen in both eyes [Figure 1]. Bilateral conjunctival chemosis and congestion were noted. Pupil examination was normal with normal reaction in both eyes. There was no relative afferent pupillary defect. Visual fields were full to confrontation, and color vision was normal. On applanation tonometry, her intraocular pressures (IOPs) were 17 mmHg in the right eye and 16 mmHg in the left eye. Hertel exophthalmometry was 20 mm in the right eye and 19 mm in the left eye. She was orthophoric in primary gaze, and all other ocular movements were normal. No diplopia was reported by the patient. Neither proptosis nor bruit was observed. Fundus examination was unremarkable.
Figure 1: Slit-lamp picture of the patient. Dilatation and increased tortuosity of episcleral vessels in (a) the right eye and (b) the left eye

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The patient was seen again after 7 days, and in review she was found to have a raised IOP of 24 mmHg bilaterally. In view of nonresolving conjunctival congestion, the presence of corkscrew vessels over conjunctiva, and raised IOP, we decided to perform an urgent neuroimaging. Magnetic resonance imaging (MRI) with angiogram of the brain revealed bilateral dilated superior ophthalmic vein with arterialized flow reversal in superior ophthalmic vein. On further evaluation by the interventional radiologist, digital subtraction angiography (DSA) revealed bilateral (right > left) indirect CCF (Barrow type D). Arterial feeders were noted from the branches of meningohypophyseal and inferolateral trunk of cavernous ICA and small branches from the middle meningeal artery, draining into the posteromedial compartment of the right and left cavernous sinus [Figure 2]. The patient was diagnosed with an indirect CCF bilaterally in view of the clinical and radiology findings. Barrow type D dural fistulas were reported to be seen bilaterally on the radiology findings; however, there were no other associated or underlying pathologies seen on the scans. The patient was reviewed ophthalmically after 4 days and was started on latanoprost eye drops. She was demonstrated carotid decompression exercises by the interventional radiologist, to be done five times a day, 10 minutes each. The patient had to press and release the common carotid artery that is palpable in the neck below the angle of the mandible for 10 minutes. She was advised to repeat this maneuver five times a day. A significant improvement was observed in conjunctival congestion after 3 weeks. She is on regular ophthalmic and interventional radiologist follow-up since then.
Figure 2: Digital subtraction angiogram of the patient. (a) Sagittal and (b) frontal section of the angiogram of brain showing connection between the dural branches of external carotid artery and internal carotid artery with cavernous sinus (Barrow type D)

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  Discussion Top

CCF results from an abnormal vascular shunt between the carotid artery and the cavernous sinus. It is commonly classified based on hemodynamics or 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 the aneurysm or medical conditions predisposing to arterial wall defects. Anatomic classification specifies whether the fistula is direct, arising from the carotid artery, or indirect, arising from one of the branches of the carotid artery.[2] Barrow classified fistulas into four types[3] [Table 1].
Table 1: Barrow classification of carotid cavernous fistula[3]

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The most common cause of CCF is trauma; however, a spontaneous CCF is not uncommon. Helmke et al.[4] suggested that a sudden increase in the intraluminal pressure ruptured the internal carotid artery, which may explain the nontraumatic cause of CCFs. Diagnosis of CCFs should be considered with bilateral eye symptoms and bilateral nerve palsies.[5] Treatment of CCFs can be medical management, surgical management, or observation depending on the type of fistulas. Type A fistulas very rarely resolve spontaneously; however, type B, C, and D fistulas have a higher incidence of spontaneous resolution.[6],[7] Some cases of indirect and low-flow fistulas can initially be observed only or managed conservatively for ocular symptoms with medical management or manual carotid compression.[8] Interventional treatment options include both surgical and endovascular options, which are ligation of the external or internal carotid arteries, fistula embolization with glue, microcoils, and stents and detachable balloons.[9]

Bilateral spontaneous indirect CCF is an uncommon presentation, and very few cases have been reported in the literature. In our literature search, we found only 35 reported cases of spontaneous nontraumatic bilateral CCF, out of which only seven were bilateral spontaneous nontraumatic Barrow type D CCF.

We are presenting the eighth case report in the overall literature of the rare bilateral Barrow type D CCF. [Table 2] shows the summary of all seven reported cases of bilateral Barrow type D fistulas.[10] Bilateral spontaneous CCFs are relatively difficult to diagnose due to lack of any prior antecedent history of trauma and relatively mild symptoms. B scan can be useful in primary diagnosis as it demonstrates dilated superior ophthalmic veins. However, MRI and DSA scans become critical in diagnosing the CCFs.
Table 2: Literature review of the reported cases of spontaneous bilateral carotid cavernous fistula Barrow type D

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  Conclusion Top

To summarize, if a delay in diagnosis of CCFs occur, it can be a threat to vision. Raised venous pressure and IOP in a CCF patient may compromise the retinal perfusion and can cause damage to the optic nerve by secondary glaucoma if CCF is left untreated for a long time. A differential diagnosis of bilateral spontaneous CCFs should be considered in patients with long-standing history of red eyes or those unresponsive to conventional topical treatment for conjunctivitis-like symptoms. Some points that can help distinguish between conjunctivitis and CCF are the presence of corkscrew vessels in CCF, absence of discharge in CCF, and nonresolution of conjunctivitis with routine treatment. This should raise suspicion among ophthalmologists that will help in early referral.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Bowling B. Kanski's Clinical Ophthalmology. Elsevier Edinburgh; 2016.  Back to cited text no. 1
Docherty G, Eslami M, Jiang K, Barton JS. Bilateral carotid cavernous sinus fistula: A case report and review of the literature. J Neurol 2018;265:453-9.  Back to cited text no. 2
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. 3
Helmke K, Krüger O, Laas R. The direct carotid cavernous fistula: A clinical, pathoanatomical, and physical study. Acta Neurochirurgica 1994;127:1-5.  Back to cited text no. 4
Karadag R, Bayraktar N, Kirbas I, Durmus M. Unilateral, indirect spontaneous caroticocavernous fistula with bilateral abduction palsy. Indian J Ophthalmol 2011;59:336-7.  Back to cited text no. 5
[PUBMED]  [Full text]  
Murthy TV, Chandra M, Gupta P, Bedi PS, Prabhakar T. Caroticocavernous fistula-A case report. Indian J Anaesth 2005;49:220-2.  Back to cited text no. 6
  [Full text]  
Naragum V, Barest G, AbdalKader M, Cronk KM, Nguyen TN. Spontaneous resolution of post-traumatic direct carotid-cavernous fistula. Interv Neurol 2018;7:1-5.  Back to cited text no. 7
Gemmete JJ, Chaudhary N, Pandey A, Ansari S. Treatment of carotid cavernous fistulas. Curr Treat Options Neurol 2010;12:43-53.  Back to cited text no. 8
Korkmazer B, Kocak B, Tureci E, Islak C, Kocer N, Kizilkilic O. Endovascular treatment of carotid cavernous sinus fistula: A systematic review. World J Radiol 2013;5:143-55.  Back to cited text no. 9
Khan S, Gibbon C, Johns S. A rare case of bilateral spontaneous indirect caroticocavernous fistula treated previously as a case of conjunctivitis. Ther Adv Ophthalmol 2018;10. doi: 10.1177/2515841418788303.  Back to cited text no. 10


  [Figure 1], [Figure 2]

  [Table 1], [Table 2]


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