Pulmonary Arteriovenous Malformation-Related Embolic Stroke Causing Thalamic Esotropia

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Pulmonary Arteriovenous Malformation-Related Embolic Stroke Causing Thalamic Esotropia Sugi Panneerselvam, BA, Bayan Al Othman, MD, Ashwini Kini, MD, Andrew G. Lee, MD Downloaded from http://journals.lww.com/jneuro-ophthalmology by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8KKGKV0Ymy+78= on 05/04/2022 T halamic esotropia (ET) is a supranuclear ocular deviation that can mimic a sixth nerve palsy. The mechanism of thalamic ET remains unclear but may be due to loss of convergence inhibition to the oculomotor nucleus and a subsequent esotropia (1). Thalamic ET can present as a pseudo-abducens palsy where the patient has difficulty abducting one or both eyes in the absence of a pontine or peripheral sixth nerve lesion (2) and is the result of tonic and a draining vein but without an intervening capillary bed. In the lung, an AVM can result in a right-to-left shunt. Although pulmonary AVM are usually asymptomatic, compensatory secondary erythrocytosis may occur to maintain arterial oxygen saturation. Pulmonary AVM, however, can result in impaired capillary filling and loss of the pulmonary capillary filter and thus may result in paradoxical emboli (e.g., bacteria, particles, and thromboemboli) that FIG. 1. Axial MRI of the brain showing small, acute right medial thalamic infarct (arrows) seen in (A) T2 fluid-attenuated inversion recovery and (B) diffusion-weighted imaging. activation of the medical rectus muscle rather than paresis of the lateral rectus (3). Pulmonary arteriovenous malformation (AVM) is an abnormal collection of blood vessels with an arterial feeder Baylor College of Medicine (SP), Houston, Texas; Department of Ophthalmology (BAO, AK, AGL), Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas; Departments of Ophthalmology, Neurology, and Neurosurgery (AGL), Weill Cornell Medicine, New York, New York; Department of Ophthalmology (AGL), University of Texas Medical Branch, Galveston, Texas; Department of Ophthalmology (AGL), University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Ophthalmology (AGL), Texas A and M College of Medicine, Bryan, Texas; and Department of Ophthalmology (AGL), The University of Iowa Hospitals and Clinics, Iowa City, Iowa. The authors report no conflicts of interest. Address correspondence to Andrew G. Lee, MD, Blanton Eye Institute, Houston Methodist Hospital, 6560 Fannin Street Suite 450, Houston, TX 77030; E-mail: [e-mail] Panneerselvam et al: J Neuro-Ophthalmol 2021; 41: e75-e76 bypass pulmonary filtration and cause cerebral abscess or ischemic strokes (4). Many pulmonary AVMs are associated with hereditary hemorrhagic telangiectasias, an autosomaldominant multisystemic vascular disease characterized by nasal and gastrointestinal telangiectasias (4). We present a case of pseudo-abducens palsy secondary to paradoxical embolic thalamic infarct from a pulmonary AVM. To the best of our knowledge, this is the first such case to be reported in the English language ophthalmic literature. CASE REPORT A 64-year-old man presented with acute, painless, binocular oblique diplopia worse when looking to the left. He also had slurred speech, uncoordinated gait, dizziness, weakness in the upper left extremity, and left upper motor neuron facial nerve palsy. Surgical history was significant for coronary artery disease, hypercholesterolemia, and an e75 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 2. Pulmonary arteriovenous malformations (AVMs) (circled) in the right lower lobe shown by (A) coronal scout and (B) coronal chest CT angiogram. asymptomatic pulmonary AVM (discovered previously on routine chest radiography in 1991). He was only taking low-dose aspirin (81 mg). Family history was significant for hypertension, stroke, and heart attack in his father. Social history was unremarkable. Ophthalmic examination showed visual acuity of 20/20 in the right eye and the left eye. He had reactive pupils with no anisocoria or relative afferent pupillary defect. Motility examination showed a limitation of abduction in the right eye with 5–10 prism diopter esotropia. Automated perimetry (24-2 Humphrey visual field) testing showed nonspecific scatter defects. The remainder of the anterior segment, intraocular pressure, and dilated fundus examinations were unremarkable in both eyes. The patient had a left upper motor neuron seventh nerve palsy (sparing the upper face), a left hemiparesis, and transient slurred speech. Computed tomography (CT) image of the brain without contrast was negative for intracranial hemorrhage. MRI of the brain showed a small, acute, right medial thalamic infarct (Fig. 1). CT angiogram (CTA) of head and neck showed no intracranial or extracranial vascular abnormality. Echocardiogram (EKG) was normal. Chest X-ray, coronal scout imaging, and coronal CTA chest showed evidence of pulmonary AVMs in the right lower lobe (Fig. 2). The AVM had a 9-mm feeding artery with an 11-mm draining vein. The central nidus was measured at 43 · 33 mm. Lower extremity venous Doppler was normal. Four days after stroke, a transesophageal echocardiogram showed relaxation impairment of left ventricular filling and a right-to-left interatrial shunt. No mass or thrombus was identified in the cardiac chambers, and only mild atherosclerotic plaque was found in the descending thoracic aorta. The patient subsequently underwent a right lower lobe AVM embolization with successful embolization of the feeding vessel. The patent foramen ovale was not patched. On follow-up 3 months later, he had almost complete resolution of the diplopia and all his previous neurologic symptoms and signs. e76 DISCUSSION Although stroke due to pulmonary AVM has been previously described, to the best of our knowledge, this is the first case describing pulmonary AVM-related thalamic stroke with esotropia and pseudo-abducens palsy. Embolism occurs most often from feeding arteries larger than 3 mm, but in this case, the patient had a 9mm feeding artery, putting him at higher risk for pulmonary AVM-induced embolic stroke (4). Furthermore, it is possible that an embolus from the pulmonary AVM could travel through the right-to-left patent foramen ovale and result in ischemic stroke as well, as it was never patched. Clinicians should be aware that thalamic esotropia can mimic a sixth nerve palsy and provide falselateralizing and false-localizing information (e.g., pseudoabducens palsy) and that pulmonary AVM can cause cerebral stroke. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: S. Panneerselvam; b. Acquisition of data: B. Al Othman; c. Analysis and interpretation of data: A. Kini. Category 2: a. Drafting the manuscript: B. Al Othman; b. Revising it for intellectual content: A. Lee. Category 3: a. Final approval of the completed manuscript: A. lee. REFERENCES 1. Han IB, Ahn JY, Kim HS. Acute esotropia secondary to thalamic hemorrhage. Kor J Cerebrovasc Surg. 2005;7:245– 248. 2. Kaas BM, Zee DS, Kheradmand A, Gold DR. Midbrain infarction resulting in bilateral pseudoabducens palsies. Neurologist. 2017;22:72–76. 3. Ghasemi M, Riaz N, Bjornsdottir A, Paydarfar D. Isolated pseudoabducens palsy in acute thalamic stroke. Clin Imaging. 2017;43:28–31. 4. Shovlin CL, Condliffe R, Donaldson JW, Kiely DG, Wort SJ. Pulmonary arteriovenous malformations emerge from the shadows. Thorax. 2017;72:1071–1073. Panneerselvam et al: J Neuro-Ophthalmol 2021; 41: e75-e76 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.