Older woman presents with progressive diplopia, eye redness and proptosis
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A 78-year-old woman was referred to the neuro-ophthalmology service at New England Eye Center for several months of progressive diplopia, bilateral eye redness and proptosis.
The patient’s medical history was significant for hyperlipidemia, diverticulosis, osteopenia and squamous cell carcinoma of the skin. Medications included aspirin, atorvastatin and vitamin D3. Past surgeries included breast biopsy and cataract surgeries in both eyes. She was a former smoker with no reported alcohol or drug use.
Eight months before presentation, she developed binocular vertical diplopia, associated with a “swooshing” sensation on the left side of her head. At that time, she was evaluated by the local emergency department for concern of stroke. CTA and MRI of the brain were grossly negative and within normal limits, except for 60% right internal carotid artery stenosis. Laboratory workup, including platelets, ESR and CRP, were within normal limits. The patient was evaluated by her ophthalmologist, and the diplopia resolved with a Fresnel prism. Two months later, the patient developed new binocular horizontal diplopia, increasing eye redness and “bulging” of both eyes. She was again evaluated by her local ophthalmologist and was found to have bilateral abduction deficits, right worse than left. There was a concern for thyroid eye disease; TPO and TSH receptor antibodies and TSH levels were normal. An MRI of the orbits was obtained, and the patient was referred to Tufts New England Eye Center for further evaluation.
Examination
Examination revealed best corrected visual acuity of 20/200 in the right eye and 20/25-1 in the left eye. Color vision by Ishihara color plates were 8/10 in the right eye and 10/10 in the left eye. The pupil exam revealed brisk, direct pupillary response with no relative afferent pupillary defect. IOPs were 36 mm Hg in the right eye and 24 mm Hg in the left eye. No ocular bruit was appreciated on auscultation. Ocular motility and alignment examination revealed esotropia and left hypertropia; the right esotropia measured greater than 45 D in right gaze and 20 D to 25 D in primary gaze as well as a small left hypertropia of 3 D. The patient was orthophoric in left gaze (Figure 1). Hertel measurement of exophthalmos demonstrated a 2 mm proptosis of the right eye.
Source: Yi Ling Dai, MD, Laurel Vuong, MD, Allison Callahan, MD, and Adel Malek, MD, PhD
Slit lamp examination was notable for bilateral but asymmetric conjunctival injection, with corkscrew vessels greater in the right eye than the left (Figures 2b and 2c). Dilated examination was unremarkable, with normal retinal and optic nerve examinations.
What is your diagnosis?
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Binocular vertical diplopia
The differential diagnosis for binocular vertical diplopia in an older patient includes giant cell arteritis and microvascular cranial nerve palsy. Other common causes of vertical diplopia include thyroid eye disease, which may present without the typical findings of proptosis and lid retraction, and brain stem infarction, which may have additional accompanying neurologic symptoms. In addition, our patient has a history of squamous cell carcinoma of the face, which could result in perineural spread, causing a partial III or IV cranial nerve palsy. Ocular myasthenia gravis is uncommon and is accompanied by other symptoms including ptosis, muscle fatigability and variable ocular motility assessments. Intraorbital masses such as lymphoma can present with proptosis and conjunctival injection. A carotid-cavernous fistula may present with intracranial noises, variable degrees of headaches, proptosis and conjunctival injection.
Our patient’s initial workup ruled out giant cell arteritis (normal ESR and CRP), and the outside imaging obtained at her stroke workup was negative for mass, recurrent squamous cell carcinoma and perineural invasion. Microvascular cranial nerve palsy should typically resolve after 3 to 4 months. Thyroid eye disease was appropriately considered given the diplopia, conjunctival injection and proptosis; however, thyroid hormone levels and thyroid antibodies were within normal ranges, making thyroid eye disease less likely. Of note, the injected conjunctiva vessels of a patient with thyroid eye disease do not typically have a distinct corkscrew configuration. The absence of characteristic enlargement of the extraocular muscles on both MRIs further argued against thyroid eye disease.
By the time she was seen at New England Eye Center, the patient’s progression and clinical examination was highly suggestive of a carotid-cavernous fistula (CCF). During her workup, an MRI of the orbits with and without contrast was obtained, which showed new enlargement of both superior ophthalmic veins, right larger than left (Figure 2a). Review of her MRI from 8 months prior showed normal-sized superior ophthalmic veins bilaterally.
She was started on IOP-lowering drops and was referred to neurosurgery for further evaluation and management. A diagnostic cerebral angiogram was performed, which confirmed the presence of a right-sided indirect CCF that was fed by both internal and external carotid artery feeder vessels (Figure 3a).
Discussion
A carotid-cavernous fistula is an abnormal vascular connection between either the internal carotid artery (ICA) or the external carotid artery (ECA) and the venous channels of the cavernous sinus. Most cases of CCF are secondary to trauma, either accidental or iatrogenic (eg, craniotomies); however, a small percentage of CCF cases are spontaneous. Spontaneous CCFs are more common in postmenopausal women and patients with musculoskeletal and/or collagen vascular-related disorders (eg, Ehlers-Danlos syndrome). CCFs are classified into direct (type A) and indirect (type B to D) types. Direct types are high-flow fistulas between the ICA and cavernous sinus and are commonly associated with trauma. By contrast, indirect CCFs are low-flow fistulas between meningeal branches of the ICA/ECA and the cavernous sinus, and they can be further subclassified based on the specific vessels that connect to the cavernous sinus.
Fistulation of the venous system results in increased vascular pressure and resistance, which impedes venous drainage and leads to vascular congestion and ischemia. Symptoms and examination findings can differ widely based on the type of CCF. Direct CCFs often present acutely with dramatic and severe symptoms of pulsatile exophthalmos, orbital bruit, chemosis, pulsatile tinnitus, diplopia, headaches and vision loss. Ophthalmoplegia may also occur secondary to cranial nerve ischemia within the cavernous sinus. Indirect CCFs are more insidious in presentation; patients present asymptomatically or most commonly with conjunctival injection. Patients with CCF often have distinct tortuous corkscrew blood vessels that occur secondary to arterialization of conjunctival and episcleral veins. Other common symptoms include chemosis, proptosis, diplopia, retro-orbital pain, elevated IOP and vision changes due to optic nerve compromise.
Diagnosis of CCF is often based on clinical presentation in conjunction with characteristic findings on imaging. CTA/MRA are noninvasive first-line options that help to exclude other entities (stroke workup), while demonstrating dilation of the superior (or inferior) ophthalmic vein typically seen in a CCF. Intracranial imaging can also demonstrate enlargement of the affected cavernous sinus. However, cerebral angiography remains the gold standard in confirming the diagnosis of a CCF.
Management of CCF depends on subtype and is tailored depending on clinical manifestations and risk for ophthalmic and neurologic complications. Comanagement with neurosurgery is imperative. In patients who are asymptomatic, conservative management and close observation may be effective. Ellis and colleagues reported that 20% to 60% of patients with indirect CCFs have spontaneous resolution of the fistula. An additional 30% of low-flow CCFs may also resolve with external carotid compression therapy. In patients with symptomatic and/or direct CCFs, the primary goal of management is endovascular closure of the fistula. Both coiling and liquid embolic agents have been the predominant methods for closing CCFs. The ipsilateral petrosal sinus (IPS) is often the preferred route for transvenous embolization; however, in cases of aberrant anatomy of the IPS (eg, exquisitely tortuous or discontinuous with the proximal jugular system), the approach may be impossible. A secondary approach often involves accessing the superior ophthalmic vein via the angular vein through the facial vein. However, these vessels have sharp angles and are often small in caliber, therefore making this approach technically difficult. Thus, in cases in which other endovascular approaches are exhausted, direct cannulation of the superior ophthalmic vein via surgical cutdown (anterior orbitotomy) is employed.
First described in 1988, the superior ophthalmic vein approach for embolization of CCFs has been successful in more than 95% of patients. The procedure is usually performed as a collaboration between an oculoplastic surgeon and a neurointerventionalist. The superior ophthalmic vein forms at the junction of the supraorbital, angular and supratrochlear veins within the superomedial orbit, 6 mm above the superior sulcus of the eyelid nasally. Once isolated, the vein is entered with an angiocatheter and advanced to the cavernous sinus, and the fistula is subsequently obliterated via either liquid embolic agents or coils. Care is taken to leave one of the ophthalmic veins patent to prevent a sudden increase in IOP. Arterial angiography is performed to confirm obliteration of the fistula.
Case resolution
An attempt to embolize the fistula via a transfemoral transverse approach was unsuccessful due to complete thrombosis at the junction between the right inferior petrosal sinus and the cavernous sinus. The patient also had high-grade stenosis of the junction of the facial vein (Figure 3b), and an external jugular and facial approach was anticipated to be unsuccessful. Therefore, oculoplastics performed an anterior orbitotomy with superior ophthalmic vein cannulation for coil embolization, and the fistula was successfully closed (Figure 4). At 2 weeks after embolization, visual acuity improved to 20/30-1 from 20/200 in the right eye; color vision also improved to 10/10 from 8/10 in the right eye. Hertel measurement improved to a 0.5 mm proptosis of the right eye. The patient reported significant improvement of her conjunctival injection and diplopia.
- References:
- Barrow DL, et al. J Neurosurg. 1985;doi:10.3171/jns.1985.62.2.0248.
- Ellis JA, et al. Neurosurg Focus. 2012;doi:10.3171/2012.2.FOCUS1223.
- Henderson AD, et al. Eye (Lond). 2018;doi:10.1038/eye.2017.240.
- Kai Y, et al. Interv Neuroradiol. 2007;doi:10.1177/15910199070130S117.
- Miller NR. Neurosurg Focus. 2007;doi:10.3171/FOC-07/11/E13.
- Miller NR, et al. J Neurosurg. 1995;doi:10.3171/jns.1995.83.5.0838.
- Shah A, et al. Superior ophthalmic vein cannulation for carotid cavernous fistula. In: StatPearls. StatPearls Publishing; Updated May 8, 2021. www.ncbi.nlm.nih.gov/books/NBK537177.
- For more information:
- Yi Ling Dai, MD, Laurel Vuong, MD, Allison Callahan, MD, and Adel Malek, MD, PhD, can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.
- Edited by Allison V. Coombs, DO, MS, and Nisha S. Dhawlikar, MD, MPH. They can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.