63-year-old male presented with a two-month history of left eye swelling
Associated with pain and horizontal diplopia
Also reports decreased vision for the past few months
Exam Findings
VAcc: 20/25-1; 20/50+1
Pupils: Round and Reactive OU, no RAPD
IOP: 10; 26
EOM: Full OD; -3 abduction OS otherwise full EOM in all other directions OS
Figure 1: External slit lamp photograph of the left eye showing injected conjunctiva with corkscrew vessels.
Figure 2: Dilated fundus exam OS revealed an intra-retinal hemorrhage nasal to the optic disc and superiorly
Differential Diagnosis
Vascular
Cavernous sinus thrombosis
Carotid-cavernous fistula
Neoplastic
Cavernous sinus tumors
Orbital tumors
Inflammatory
Thyroid orbitopathy
Idiopathic Orbital Inflammation
Sarcoidosis
Infectious
Orbital cellulitis
Mucormycosis
Additional Investigations
A CT/CTA of the patient’s brain was performed, given high suspicion for a cavernous sinus lesion (Note: MRI was not performed since patient has a pacemaker).
Cerebral angiogram was performed and showed a left carotid cavernous fistula fed by branches of the left external carotid artery and, to a lesser degree, the right external carotid artery and left internal carotid artery.
Figure 3: CT angiography of the brain post-contrast shows enlargement of the left superior ophthalmic vein (red arrow) with early filling of the left cavernous sinus suggestive of an underlying carotid cavernous fistula. Also, a 1 mm aneurysm arising from the distal cavernous segment of the left internal carotid artery was noted (white arrow).
Diagnosis
Dural carotid cavernous fistula
Pathophysiology
Direct carotid cavernous fistula – Arise most commonly secondary to a traumatic tear of internal carotid artery within the cavernous sinus. It can also rarely arise secondary to a spontaneous aneurysm rupture.
Dural carotid cavernous fistula – Arise from connections between dural branches of the internal or external carotid arteries and the cavernous sinus. Pathophysiology is somewhat unknown. Two major hypotheses:
Associated with occlusion of adjacent draining venous dural sinuses. This results in arterialization of venous blood flow and subsequent formation of an arteriovenous shunt.
Arise from congenital arteriovenous shunts that are normal variants. Often in the setting of hypertension / atherosclerotic disease, these congenital shunts proliferate into a carotid cavernous fistula.
Treatment
The patient was started on Cosopt (dorzolamide hydrochloride-timolol maleate)for the elevated IOP in the left eye
Neurosurgery was consulted for angiography and embolization of the left carotid cavernous fistula
Figure 4: Cerebral angiography following coil embolization demonstrating complete obliteration of the fistula with no filling of the carotid cavernous fistula or left superior ophthalmic vein.
Prognosis and Future Directions
The overall prognosis for dural CCF is very good. There is very minimal increase in mortality rates and generally 20 to 50 percent of cases spontaneously resolve.
Patients with mild ocular symptoms can be closely monitored with regular ophthalmology exams (checking visual acuity, IOP, EOM and dilated fundus exam).
Patients with mild exposure keratopathy can be treated with aggressive lubrication.
Patients experiencing diplopia can be treated with prism or occlusion therapy and IOP-lowering medications can be started if IOP is substantially elevated.
The main indications for intervention with angiography are: visual deterioration, intolerable diplopia, elevated IOP despite maximal medical therapy, proliferative retinopathy, proptosis with untreatable corneal exposure and patients with cortical venous drainage.
Transvenous embolization is typically used when intervention is necessary. In difficult cases, retrograde cannulation of superior or inferior ophthalmic vein can be performed to access the CCF for coiling.
Successful closure is reported to occur in 80 to 100 percent of cases following embolization.
References
Miller NR. Neurosurg Clin N Am. 2012 Jan;23(1):179-92.
Barrow DL, Spector RH, Braun IF, et al. Classification and treatment of spontaneous carotid-cavernous sinus fistulas. J Neurosurg.1985 Feb;62(2):248-256.
Miller NR. “Carotid-Cavernous Sinus Fistulas,” Walsh and Hoyt’s Clinical Neuro-Ophthalmology, 6th ed. (Baltimore: Lippincott, Williams & Wilkins, 2005) pp. 2263-2296.
Ang M, Sng C, Milea D. Optical coherence tomography angiography in dural carotid-cavernous sinus fistula. BMC Ophthalmol. 2016 Jul 7;16:93.
Debrun GM, Viñuela F, Fox AJ, et al. Indications for treatment and classification of 132 carotid-cavernous fistulas. Neurosurgery. 1988 Feb;22(2):285-9.
Ishijima K, Kashiwagi K, Nakano K, et al. Ocular manifestations and prognosis of secondary glaucoma in patients with carotid-cavernous fistula. Jpn J Ophthalmol. 2003;47:603-8.
Contact
Jonathan Kim, MD, Associate Professor of Clinical Ophthalmology, jonkim@chla.usc.edu
