Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis Presenting as Idiopathic Orbital Inflammatory Syndrome

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis Presenting as Idiopathic Orbital Inflammatory Syndrome Sushant Wagley, MD, Yao Wang, MD, Collin M. McClelland, MD, John J. Chen, MD, PhD, Michael S. Lee, MD Downloaded from http://journals.lww.com/jneuro-ophthalmology by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8K2+Ya6H515kE= on 05/04/2022 A 47-year-old woman presented to an outside institution with right eye vision loss, eyelid erythema, and edema, ptosis, and pain worse with eye movements. Orbital MRI reportedly showed right optic nerve enhancement concerning for optic neuritis (ON). Workup including Lyme, quantiferon, aquaporin-4 immunoglobulin, and lumbar puncture was normal. She received only 2 doses of intravenous methylprednisolone 1 g daily because she developed pancreatitis. Her treatment was switched to plasmapheresis without significant improvement. On referral to neuro-ophthalmology, her examination showed visual acuity of hand motion in the right eye and 20/20 in the left eye. A brisk right afferent pupillary defect (APD) was present. External examination showed right upper- and lower-eyelid edema, 2 mm of ptosis, periorbital redness, conjunctival chemosis, and 1+ conjunctival injection (Fig. 1). She noted decreased sensation in the right trigeminal (V2) distribution to light touch. Hertel exophthalmometry showed 2-mm relative proptosis in the right eye. Sensorimotor examination revealed a supraduction deficit in the right eye. Slit-lamp examination demonstrated 1+ anterior vitreous cells, and fundus examination showed 3+ optic disc edema with optic nerve hemorrhages in the right eye. Examination was unremarkable in the left eye. Additional laboratory test results, including urinalysis, treponemal antibodies, angiotensin-converting enzyme, antinuclear antibodies, antineutrophil cytoplasmic antibodies, and immunoglobulin G (IgG) subclass panel were normal. Myelin oligodendrocyte glycoprotein (MOG) antibody was positive (1:20). Re-review of the outside MRI revealed enhancement of the right optic nerve, sheath, and adjacent orbital fat (Fig. 2A, B). There were no signs of extraocular muscle enlargement or other white-matter lesions on imaging. She received intravenous methylprednis- olone 1 g daily followed by 2 rituximab infusions 14 days apart with a plan to repeat infusions 6 months later. She was discharged home on oral prednisone 80 mg/d tapering by 10 mg/d each week. Three months later, right eye acuity had improved to 20/ 20 with a persistent APD. The right eye disc edema resolved. One month later, she developed severe rightsided headache and eye pain due to recurrent ON. Her acuity was 20/100. She received high-dose oral prednisone (1,250 mg · 3 days), which improved her pain and visual acuity to 20/60. Her prednisone was tapered to 20 mg daily over 1 month. We present an unusual case of orbital inflammation and ON secondary to MOG-IgG. This report highlights an unusual occurrence of symptomatic orbital inflammation with MOG-IgG–associated disease. MOG-IgG–positive patients can have a diverse inflammatory course. This condition is most commonly characterized by severe attacks of ON, longitudinally extensive transverse myelitis, or acute disseminated encephalomyelitis (1,2). Patients with MOGIgG–positive ON commonly present with pain with extraocular movements and optic disc edema as seen in our patient. However, our patient’s prominent presenting orbital signs including eyelid edema and erythema, proptosis, and extraocular motility limitations are features seen in idiopathic orbital inflammation (IOI) (3,4). This patient also presented with anterior vitreous cells, which have been previously documented in cases of MOG-IgG ON (5) but are more consistent with IOI. She experienced a typical course of MOG-IgG ON with a nadir acuity of hand motion later improving to 20/20 with immunosuppression (2). Our patient’s recurrence of Department of Ophthalmology and Visual Neurosciences (SW, YW, CMM, MSL), University of Minnesota, Minneapolis, Minnesota; and Department of Ophthalmology and Neurology (JJC), Mayo Clinic, Rochester, Minnesota. The authors report no conflicts of interest. Address correspondence to Michael S. Lee, MD, Department of Ophthalmology and Visual Neurosciences, University of Minnesota, 420 Delaware St. SE/MMC 493, Minneapolis, MN 55455; E-mail: [e-mail] e46 FIG. 1. External photograph showing right eyelid edema and erythema. Conjunctival edema and erythema are also present. Wagley et al: J Neuro-Ophthalmol 2021; 41: e46-e47 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 2. Axial (A) and coronal (B) postcontrast MRI showing enhancement of over 50% of the prechiasmatic right optic nerve along with enhancement of the sheath and orbital tissue. ON is also typical of MOG-IgG ON. The MRI findings in MOG-IgG–positive cases include extensive involvement of the optic nerve often with perineural and orbital fat enhancement, which were observed in this case. Therefore, it follows that the orbital inflammation seen on MRI could result in orbital signs and symptoms. However, although she had limitation in extraocular motility, there were no signs of muscle enlargement on MRI. The ocular motility deficit may have occurred from inflammation of the third nerve especially since she had concomitant ipsilateral V2 numbness. The deficit may also have been restrictive process with orbital congestion limiting elevation of the eye. This case’s unusual presentation of orbital inflammation and ON highlights the broad spectrum of clinical presentations seen in MOG-IgG–associated disease. MOG-IgG– associated disease is a relatively newly described disorder, and we are still discovering its complete clinical picture. Our case illustrates that patients presenting with what seems to be IOI and optic neuropathy may warrant MOG-IgG testing. STATEMENT OF AUTHORSHIP Category 1: a. conception and design: S. Wagley, Y. Wang, and M. S. Lee; b. acquisition of data: S. Wagley, Y. Wang, and M. S. Lee; c. analysis and interpretation of data: C. M. McClelland and J. J. Chen. Category 2: a. drafting the manuscript: S. Wagley and Y. Wang; b. revising it for intellectual content: M. S. Lee, C. M. McClelland, and Wagley et al: J Neuro-Ophthalmol 2021; 41: e46-e47 J. J. Chen. Category 3: a. final approval of the completed manuscript: S. Wagley, Y. Wang, C. M. McClelland, J. J. Chen, and M. S. Lee. REFERENCES 1. 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