Maxillary artery pseudoaneurysm causing retinal artery occlusion

Abstract

Purpose

To report a novel case of central retinal artery occlusion in a 44-year-old male caused by emboli from a non-traumatic maxillary artery pseudoaneurysm.

Observations

A 44-year-old male with history of hypertension presented to clinic with painless vision loss in his left eye. He was found to have a central retinal artery occlusion. Ocular massage and intraocular pressure lowering agents were administered and the patient was transferred to the emergency department for cerebrovascular work-up. Remarkably, the patient had rapid symptom improvement from no light perception to 20/70 after ocular massage and IOP agents. Neuroimaging studies discovered a maxillary artery pseudoaneurysm with anastomotic branches to the internal carotid artery via the foramen rotundum and Vidian artery. Endovascular embolization was performed to prevent further thromboembolic event.

Conclusion and Importance

We believe this to be the first reported case of retinal artery occlusion caused by a maxillary artery pseudoaneurysm. This case demonstrates that visual deficits can be the presenting symptom of a non-traumatic maxillary artery pseudoaneurysm.

1. Introduction

Central retinal artery occlusion (CRAO) is an ophthalmological emergency often associated with poor outcomes. Occlusion can result from a variety of conditions resulting in a compromised blood flow to the retina with embolism being the most common cause.¹ There have been rare, reported cases of CRAO caused from internal carotid artery dissection but no reported cases of maxillary artery pseudoaneurysm as the source of embolism.² Maxillary artery pseudoaneurysms have rarely been reported in the literature and are often the result of trauma or maxillofacial surgeries.³

2. Case report

A 44-year-old male with a history of hypertension and prior corrective orthognathic surgery eight years prior presented to ophthalmology clinic with painless vision loss in his left eye for 90 min. He endorsed no other symptoms other than a brief episode of jaw pain that morning which subsided. He reported no recent trauma. Initial visual acuity was OD, 20/20 and OS, no light perception (NLP). Confirmatory testing by the on duty ophthalmologist found visual acuity of OD 20/20 and OS hand motion. Prior visual acuity was 20/20 OU. Initial fundus examination demonstrated multiple tan opacities within the arterioles OS and slight whitening of the retina compared to OD (see Fig. 1). A presumed diagnosis of central retinal artery occlusion was made and ocular massage was performed as well as ophthalmic intraocular pressuring lowering agents, dorzolamide 2%/timolol 0.5% and brimonidine 0.2%, and the patient was admitted for cerebral vascular accident (CVA) evaluation.

Fig. 1.

Fundoscopic imaging demonstrating slight pallor of the OS macula with multiple emboli visualized in arteries/arterioles throughout the superior and inferior arcades. At this stage, the emboli had progressed distally through the arterioles from initial examination consistent with the improvement in visual acuity.

Initial CVA work-up was initiated. Computed tomography angiography (CTA) of the head and neck revealed a mass within the left midface. Remarkably, despite no additional intervention the patients vision returned from NLP to OS 20/70 quickly after presentation. On hospital day two, his vision had returned to OS 20/20 with a small remaining deficit present in the centronasal visual field correlating with one small area of leakage on intravenous fluorescein angiography (IVFA) demonstrated in Fig. 4. Due to the improvement from a central retinal artery occlusion to a branch retinal artery occlusion management was continued with aspirin without the addition of thrombolytics. Further MRI, and Triplanar CTA reconstruction, demonstrated no areas of infarct in the brain but did reveal a left maxillary artery pseudoaneurysm which was largely filled with thrombus and calcified (see Fig. 2) (see Fig. 3).

Fig. 4.

Fluorescein angiography performed two days after initial presentation demonstrating normal arterial phase circulation of the right eye. Late recirculation phase of the left eye demonstrates grossly normal circulation with one single foci of late leakage correlating with persistent visual field deficit. Follow-up fundoscopic images performed two days after initial presentation still demonstrating slight pallor of the OS macula, but showing resolution of prior emboli.

Fig. 2.

Preop MRI demonstrating spherical, T2 primarily hypointense, T1 iso- and hyperintense mass within left masticator space, consistent with clotted blood within pseudoaneurysm.

Fig. 3.

Triplanar CTA reconstruction demonstrating peripherally-calcified mass in the area of the abnormality seen on MRI, which appears to arise from the distal maxillary artery with contrast filling of an aneurysm adjacent to the calcification. Appearance is typical for a partially thrombosed pseudoaneurysm.

The remainder of the CVA work-up, including electrocardiogram and transthoracic echocardiogram, was unremarkable and it was hypothesized that the emboli causing the retinal artery occlusion originated from the maxillary artery pseudoaneurysm and traveled to the internal carotid artery and distally to the retinal artery via an anastomotic branch.

After neurosurgical consultation, the patient elected for an endovascular occlusion of the maxillary artery pseudoaneurysm to prevent further thromboembolic events. Angiography demonstrated dissecting left maxillary pseudoaneurysm with anastomotic branches between the maxillary artery and left internal carotid artery via the Vidian artery and artery of the foramen rotundum.

Endovascular embolization using coils and liquid embolic system was then performed with post embolization angiography demonstrating no residual aneurysm filling as seen in Fig. 5C (see Fig. 6).

Fig. 5.

(A) Left internal carotid artery digital subtraction angiogram, late arterial phase, lateral projection. Image demonstrates distal filling of the artery of foramen rotundum (maxillary anastomosis not visible) and Vidian artery with its connection to the descending palatine artery and slight retrograde filling of distal maxillary artery. (B) Left external carotid artery digital subtraction angiogram; mid-arterial phase, AP & lateral projections demonstrating tapering of the maxillary artery consistent with dissection of the vessel (versus external compression from the thrombosed pseudoaneurysm), the partially thrombosed pseudoaneurysm itself, and filling of the artery of foramen rotundum from the distal maxillary artery. (C) Post-embolization left ECA digital subtraction angiogram; mid-arterial phase, AP & lateral projections. Demonstrates occlusion of the maxillary artery and no residual aneurysm filling.

Fig. 6.

Post-embolization skull XR showing coils in the distal maxillary artery with Onyx filling the sac of the pseudoaneurysm and the proximal maxillary artery.

3. Discussion

This case demonstrates that ocular manifestations can be the presenting symptom of a non-traumatic maxillary artery pseudoaneurysm. This case highlights that dissection/pseudoaneurysms of the maxillary artery, or other external carotid artery branches, can also be the cause of retinal artery occlusions and should be included in the differential diagnosis; especially if there was preceding history of penetrating trauma or maxillofacial surgery. It should be noted that this case does not follow the typical course of CRAO as it presented with only mild whitening of the retina and with reports of NLP vision, although this was not confirmed on subsequent exam. It is theorized that there may have been embolic phenomena that initially and temporarily occluded the ophthalmic artery but quickly passed to the central retinal artery and then showered multiple emboli through the retina arteriole network. This is supported by the rapid improvement of vision and the tan opacities seen throughout the arteriole network moving more distally on subsequent exam throughout the morning of presentation. By day 2 after presentation, the opacities had completed disappeared as demonstrated in Fig. 4.

Retinal artery occlusions result from the blood flow to the retinal artery being compromised by embolism, autoimmune, hematologic, or systemic vascular conditions.¹ Embolus from atherosclerotic disease is the most common cause. The annual incidence of CRAO is 1/100,000.⁴ Presentation is typically a complaint of painless monocular vision loss. Risk factors are similar to those seen in cerebral vascular events; coronary artery disease, history of tobacco use, atrial fibrillation, carotid artery disease and diabetes are all common risk factors.⁵ Patients presenting with CRAO typically have visual acuity of 20/400 or worse. Overall prognosis is typically poor even in cases with spontaneous reperfusion. Only 10% of patients will have a 3-line improvement on the Snellen Chart.⁵ This patient, remarkably, had significant improvement in visual acuity from reports of NLP on presentation to 20/70 within a few hours. Early presentation within 2 h of symptoms onset allowed for rapid intervention with intraocular pressure lowering drops and ocular massage which may have aided in dislodging the emboli. While these interventions have not consistently shown better outcomes than the natural history of the disease, total time of occlusion correlates to final visual outcome and in this patient the rapid dislodging of emboli likely resulted in preserved visual acuity.

Pseudoaneurysms typically occur after there has been an incomplete tear in the blood vessel wall resulting in a hematoma either contained within the vessel adventitia or the surrounding soft tissue. They typically result from blunt or penetrating trauma, although post-radiation vasculopathy, inflammatory vasculitis, or spontaneous vessel dissection can also lead to pseudoaneurysm formation. Maxillary artery pseudoaneurysms are rarely presented in the literature but have been reported from facial trauma or as complications following orthognathic or ear, nose, and throat surgeries.³ The clinical presentation can be variable as lesions can be immediately symptomatic, present months later, or remain asymptomatic. Spontaneous thrombosis has been reported but the frequency appears to remain unpredictable. Due to their variable nature prompt treatment is often recommended. In the modern era, angiography with endovascular embolization is the gold standard for diagnosis and treatment of pseudoaneurysms of the head and neck.^3,6

There have been two reported cases of maxillary artery pseudoaneurysm embolization complicated by CRAO. Each of these two cases also showed collateral blood flow from the maxillary artery to the ophthalmic artery.⁷ Anastomotic branches from the external to internal carotid artery are common, and many are well described and of particular relevance to neurosurgeons or interventional radiologists who routinely perform embolizations in the head and neck. They tend to be small enough to be below the resolution of non-invasive vascular imaging modalities, and therefore may be incorrectly assumed to be clinically irrelevant. In pathological states however, like carotid stenosis or occlusion, these anastomoses are enlarged and provide vital collateral circulation to the brain; in other situations, such as skull base tumors or arteriovenous fistulae, enlarged collateral vessels may provide valuable avenues for therapeutic interventions.

We believe this to be the first case of CRAO occurring spontaneously rather than as an iatrogenic complication of surgical embolization of the maxillary artery. Furthermore, it demonstrates that undiagnosed maxillary artery pseudoaneurysm can also cause retinal branch occlusions and further supports early embolization of these pseudoaneurysms. While there is reported risk of visual impairment with arterial embolization, it remains the standard for treatment for vascular pseudoaneurysms and this case demonstrates that vision loss can also occur spontaneously prior to embolization. Thorough study of pre-embolization angiograms, detailed knowledge of possible “dangerous” anastomoses, and judicious selection of embolic materials should allow for safe and effective treatment of these lesions and other vascular abnormalities involving the external carotid branches.

Patient consent

Written consent to publish this case has not been obtained. This report does not contain any personal identifying information.

Funding

No funding or grant support".

Authorship

All authors attest that they meet the current ICMJE criteria for Authorship.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.