Carotid-Cavernous Fistula Presenting With Bilateral Abducens Palsy.

Abstract

HomeStrokeVol. 51, No. 6Carotid-Cavernous Fistula Presenting With Bilateral Abducens Palsy Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReview ArticlePDF/EPUBCarotid-Cavernous Fistula Presenting With Bilateral Abducens Palsy Teng J. Peng, MD, Christoph Stretz, MD, Razaz Mageid, MD, Brian Mac Grory, MB, BCh, BAO, MRCP, Shadi Yaghi, MD, Charles Matouk, MD and Joseph Schindler, MD Teng J. PengTeng J. Peng Correspondence to Teng J. Peng, MD, Department of Neurology, Yale School of Medicine, 15 York St, LLCI 910, PO Box 208018, New Haven, CT 06520. Email E-mail Address: [email protected] https://orcid.org/0000-0002-0576-1402 From the Department of Neurology (T.J.P., C.S., R.M., J.S.), Yale School of Medicine, New Haven, CT *Drs Peng and Stretz contributed equally. Search for more papers by this author , Christoph StretzChristoph Stretz From the Department of Neurology (T.J.P., C.S., R.M., J.S.), Yale School of Medicine, New Haven, CT Department of Neurology, The Warren Alpert Medical School of Brown University, Providence, RI (C.S., B.M.G.) *Drs Peng and Stretz contributed equally. Search for more papers by this author , Razaz MageidRazaz Mageid From the Department of Neurology (T.J.P., C.S., R.M., J.S.), Yale School of Medicine, New Haven, CT Search for more papers by this author , Brian Mac GroryBrian Mac Grory Department of Neurology, The Warren Alpert Medical School of Brown University, Providence, RI (C.S., B.M.G.) Search for more papers by this author , Shadi YaghiShadi Yaghi Department of Neurology, NYU Langone Health, New York, NY (S.Y.). Search for more papers by this author , Charles MatoukCharles Matouk Department of Neurosurgery (C.M.), Yale School of Medicine, New Haven, CT Search for more papers by this author and Joseph SchindlerJoseph Schindler From the Department of Neurology (T.J.P., C.S., R.M., J.S.), Yale School of Medicine, New Haven, CT Search for more papers by this author Originally published16 Apr 2020https://doi.org/10.1161/STROKEAHA.120.029306Stroke. 2020;51:e107–e110Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: April 16, 2020: Ahead of Print Case HistoryA 68-year-old woman with hypertension, hyperlipidemia, and paroxysmal atrial fibrillation not on anticoagulation due to prior gastrointestinal bleeding, presented to our hospital with 2 days of binocular diplopia and headaches. She described the diplopia as seeing 2 images side by side, worse when focusing on far-away objects. Diplopia was accompanied by persistent bifrontal headache, worse with coughing. She denied any recent fevers, trauma, retroorbital pain, blurry vision, or other associated focal neurological symptoms.On initial evaluation in the emergency room, she was afebrile and normotensive. Ophthalmologic examination at that time was notable for subtle bilateral restriction in eye abduction, but otherwise intact visual fields and normal pupillary reflexes. The remaining neurological exam was normal. A computed tomography (CT) angiogram of the head and neck showed left vertebral artery occlusion of the V1-2 segments. Follow-up magnetic resonance imaging of the brain showed no acute ischemia, and magnetic resonance angiogram of the neck with dissection protocol, including T1 fat saturation sequences, revealed a chronic vertebral occlusion, without evidence of acute dissection. Given partial resolution of symptoms, she was discharged home, with close ophthalmology and neurology follow-up to continue further workup of her diplopia.Over the next 10 days, the patient had recurrence of headaches, worsening diplopia, and developed swelling of her left eye, prompting her to return to the hospital. On re-examination, she was found to have erythema around her left eye and prominent bilateral restriction in eye abduction, left greater than right, indicative of a bilateral sixth nerve palsy. On cover uncover test, bilateral esotropia was noted. The rest of her cranial nerve and neurological exam were unremarkable. She had full visual fields, normal funduscopic exam, and visual acuity of 20/30 bilaterally. A brain magnetic resonance angiogram and magnetic resonance venogram with contrast (Figure 1) showed increased, asymmetrical enhancement of the left cavernous sinus, as well as a left dilated superior ophthalmic vein, suggestive of a carotid-cavernous fistula (CCF), but no venous sinus thrombosis. Cerebral angiography confirmed a direct CCF, which was deemed to be due to a ruptured cavernous internal carotid artery (ICA) aneurysm. The CCF was treated with a 2-stage endovascular procedure: (1) flow diverter stent reconstruction of the left cavernous ICA followed by (2) transvenous coil embolization of the fistula (Figure 2).Download figureDownload PowerPointFigure 1. Contrast-enhanced magnetic resonance angiogram (MRA) of the head with findings suggestive of a carotid-cavernous fistula (CCF). Asymmetrical enhancement of the left cavernous sinus (A) and dilatation of left superior ophthalmic vein (B). Cerebral angiography of the left internal carotid artery (ICA), red arrow points at location of CCF. These images also show early opacification of the right cavernous sinus via the intracavernous sinuses (C).Download figureDownload PowerPointFigure 2. Cerebral angiography showing endovascular treatment of the fistula. Images immediately post-treatment (A and B) and repeat angiography at 6 mo (C) confirming complete obliteration of the carotid-cavernous fistula.DiscussionThe evaluation of diplopia should begin by distinguishing monocular from binocular diplopia. Monocular diplopia is usually an ophthalmologic problem due to an optical aberration, while binocular diplopia is most likely due to a neuropathy, myopathy, or neuromuscular junction disorder; and may also occur due to brain stem strokes.1 Our patient presented with binocular diplopia, worse with far-away objects, suggesting a deficit in eye abduction. A mild bilateral abducens palsy was appreciated on her initial neurological examination but was more evident on re-presentation ten days later.The differential diagnosis for bilateral abducens nerve palsy is broad, but if diplopia is of sudden onset, vascular etiologies such as aneurysms with subarachnoid hemorrhage, vascular malformations, or ischemic stroke need to be considered. The mechanism is usually indirect by raised intracranial pressure.2While acute ischemic stroke affecting the abducens nucleus and fascicles in the pons more commonly accounts for unilateral sixth nerve palsy, given our patient’s vascular risk factors and the finding of vertebral artery occlusion on CT angiography (CTA), we considered stroke as a possible, albeit unlikely cause in our patient. Other potential causes of bilateral abducens nerve palsy include (1) infective or infiltrative diseases such tuberculosis and syphilis; (2) demyelinating diseases such as multiple sclerosis; (3) increased intracranial pressure due to space-occupying lesions or idiopathic intracranial hypertension, which can affect the abducens nerve as it transverses in the prepontine cistern; (4) pathology in the cavernous sinus such as cavernous ICA aneurysm, CCF or infection that can affect the abducens nerves as they course through the cavernous sinus (since both cavernous sinuses communicate with one another); and (5) or in some rare instances, thyroid eye disease.2Although most differential diagnoses above were considered at the time of initial presentation, the diagnosis of CCF became more obvious with her second presentation due to erythema around her left eye and more prominent bilateral abducens palsies. Her diagnosis was ultimately confirmed with cerebral angiography.A CCF is an acquired vascular malformation with abnormal connection between the carotid artery and the cavernous sinus.3 CCFs are classified based on angiographic anatomy (direct versus indirect/dural), hemodynamics (high versus low flow) and pathogenesis (traumatic versus spontaneous).4 Direct CCFs (Barrow type A) are due to direct communication between the cavernous carotid and the cavernous sinus (Figure 3).Download figureDownload PowerPointFigure 3. Barrow classification of carotid-cavernous fistulas. Direct (A) and indirect (B–D) carotid-cavernous fistula subtypes. Adapted from Ellis et al5 with permission. Copyright ©2012, Neurosurgical Focus.Direct CCFs tend to be high flow and are usually caused by significant head trauma. They may also result from iatrogenic carotid injury, most commonly during transsphenoidal surgery for resection of sellar tumors.3 Less commonly, they can arise due to the rupture of a cavernous ICA aneurysm or spontaneously.6 Indirect or dural CCFs (Barrow type B, C, and D; Figure 3) are abnormal communications between branches of the internal carotid (type B), the external carotid artery (type C), or both (type D) and the cavernous sinus.4 The pathophysiology of indirect CCFs is thought to be due to primary thrombosis of the cavernous sinus outflow, which causes a compromised egress of normal blood through the venous system and the subsequent formation of an arteriovenous fistula.7 Indirect CCFs are low flow and may occur in the setting of systemic hypertension, fibromuscular dysplasia, or Ehlers-Danlos type IV8.Our patient had a direct high-flow CCF that most likely occurred spontaneously due to rupture of a cavernous ICA aneurysm. Clinical symptoms and signs of CCF depend on a variety of factors, including fistula size, location in the cavernous sinus, drainage route (anterior, posterior, or both) and rate of blood flow.5Direct, high-flow CCF usually present suddenly if a result from trauma or aneurysmal rupture, often with rapid progression of symptoms.5 Characteristic clinical signs and symptoms result from arterialization of orbital veins and include proptosis, chemosis, orbital bruits, headaches, and visual complaints including diplopia, blurry vision, and orbital pain.8 Diplopia may result from cranial nerve involvement in the cavernous sinus (III, IV, and VI), with CN VI sixth nerve most often affected given its proximity to the internal carotid artery.8 While most cases of CCF involve the ipsilateral cavernous sinus and abducens nerve, flow and pressure can be transmitted to the contralateral cavernous sinus and affect the contralateral abducens nerve.5 Intracerebral or subarachnoid hemorrhage may occur in the setting of cortical venous drainage in about 5% of patients.5Indirect, low-flow CCF often present more gradually, most commonly with conjunctival injection. Common findings may include arterialization of conjunctival veins, chemosis, proptosis, diplopia and ophthalmoplegia, headaches and reduced visual acuity.5 Symptoms often depend on flow rate, pattern of venous drainage and pressure within the venous sinuses and may change based on development and resolution of thrombosis.5The diagnosis of CCF can be suspected clinically and is confirmed with neuroimaging. Contrast-enhanced CTA or magnetic resonance angiography are useful screening tests (87% and 80% sensitivity, respectively) but the gold standard is cerebral angiography (94.4% sensitivity).9Treatment options for CCFs include endovascular therapy, radiation therapy, open surgery, and conservative management. Endovascular therapy procedures are commonly recommended as first-line treatment.10 Delays in diagnosis or failure to treat can cause rapidly progressive and irreversible loss of vision.3This clinical case highlights the importance of including CCF in the differential diagnosis for binocular horizontal diplopia, especially when the neurological exam is otherwise equivocal. Noninvasive imaging studies with CTA or magnetic resonance angiogram may be suggestive and associated findings may provide additional clues: concomitant skull fractures may be seen in traumatic, direct CCF,5 and ophthalmic vein dilatation may be more pronounced with direct fistulas. On cerebral angiography, rapid filling of the cavernous sinus, with minimal or no filling of the intracranial vasculature are classically seen with direct CCF.3On retrospective review of the patient’s initial CTA head and neck, we noticed subtle dilatation of the left superior ophthalmic vein, which could have pointed to the diagnosis of CCF, had it been considered at the time. Fortunately, our patient had close outpatient follow-up and returned before developing any vision loss. She has mild residual diplopia and continues to follow-up in the vascular neurology and neurosurgery clinic.Teaching PointsCarotid-cavernous sinus fistulas should be considered as part of the differential diagnosis for any patient presenting with a new ophthalmoplegia.Computed tomography angiography and magnetic resonance angiogram (contrast-enhanced and time-of-flight) are useful noninvasive imaging modalities, and catheter angiography remains the gold standard.9Direct, high-flow carotid-cavernous sinus fistulas commonly present acutely and symptoms may progress rapidly with a higher risk of complications if left untreated.Patients in whom a diagnosis of carotid-cavernous sinus fistulas is made must be promptly considered for neurovascular intervention, as delayed treatment can lead to irreversible vision loss.3,5AcknowledgmentsDrs Peng, Stretz, and Mageid devised the concept and prepared the article. Drs Stretz, Schindler, Matouk, Yaghi, and B. M. Grory interpreted neuroimaging and revised the article. All authors reviewed pertinent literature.DisclosuresDr Stretz received a Neurocritical Care Society 2017 Annual Meeting Travel grant. Dr Yaghi received funding from Medtronic and institutional funding for outcome adjudication in the Stroke AF trial. The other authors report no conflicts.Footnotes*Drs Peng and Stretz contributed equally.Correspondence to Teng J. Peng, MD, Department of Neurology, Yale School of Medicine, 15 York St, LLCI 910, PO Box 208018, New Haven, CT 06520. Email teng.[email protected]edu