Bilateral Anterior Ischemic Optic Neuropathy Due to Giant Cell Arteritis With Preservation of Central Visual Acuity

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Guor Wang, MD Bilateral Anterior Ischemic Optic Neuropathy Due to Giant Cell Arteritis With Preservation of Central Visual Acuity Laura Donaldson, MD, PhD, Edward Margolin, MD G Address correspondence to Edward Margolin, MD, FRCSC, Dipl, ABO, University of Toronto, Department of Ophthalmology and Visual Sciences, Department of Medicine, Division of Neurology Chief of Service, Neuro-Ophthalmology, 801 Eglinton Avenue West, Suite 301, Toronto ON M5N 1E3; E-mail: [e-mail] right vertebral artery with concentric enhancement of the vessel wall (Fig. 2A). MRI of the orbits performed 2 weeks after treatment with steroids was normal with no evidence of optic perineuritis (Fig. 2B). This man presented with evidence of both ischemic optic neuropathy and retinopathy, indicating involvement of 2 separate ocular circulations because the optic nerve head is supplied by branches of short posterior ciliary arteries (SPCAs) and inner retina is supplied by branches of central retinal artery (CRA). MRI angiography also showed evidence of vasculitis involving the extracranial right vertebral artery. These findings were overwhelmingly supportive of a diagnosis of vasculitis, and GCA was confirmed on temporal artery biopsy. Given the presence of bilateral AION and cotton wool spots, both SPCA and CRA were likely involved by vasculitis. Although involvement of both SPCA and ophthalmic and/or CRA is not uncommon in GCA and has been previously demonstrated in histopathologic specimens, our case is very unusual because this involvement of dual circulations is typically associated with devastating visual loss (2). There is one reported case of GCA with AION as presentation, where count fingers vision at presentation improved to 20/60 after prompt treatment with steroids and an autopsy one month later demonstrated resolving vasculitis limited to SPCAs with sparing of central retinal and ophthalmic arteries as well as pial vessels (3). We hypothesize that our patient had a similar, milder arteritis that produced incomplete occlusion of both SPCA and central retinal artery. Another potential explanation for the spared central vision in our case is that central retinal artery ischemia was accompanied by selective involvement of the pial branches supplying anterior intraorbital optic nerve along its outer circumference producing optic perineuritis. Pallid optic nerve head edema is typically caused by involvement of SPCAs; however, disc edema with spared central acuity has been reported in optic perineuritis caused by GCA (5). In perineuritis, ischemia predominantly affects peripheral optic nerve axons supplied by the pial branches and often spares the central ones that carry fibers from papillomacular bundle responsible for central vision (4,5). Although MRI of the orbits with contrast in our patient did not show Donaldson and Margolin: J Neuro-Ophthalmol 2022; 42: e479-e481 e479 iant cell arteritis (GCA) involving ocular circulation is typically associated with severe, irreversible vision loss (1). We describe a man with bilateral anterior arteritic ischemic optic neuropathy (AION) and retinal ischemia due to biopsy-proven GCA who had severe peripheral vision loss with remarkable sparing of central visual acuity. We review the prevalence of preserved central vision in AION due to GCA and propose potential mechanisms by which this may occur. A 72-year-old man presented with a 3-month history of scalp tenderness, followed by new onset headache and tongue claudication. He noticed a change in his vision 2 weeks before his presentation that he described as “washedout” appearance of objects viewed from each eye. He then experienced an episode of severe dizziness when he fell and was unable to get up for 1 minute. In the emergency department (ED), he was found to have elevated C-reactive protein (27 mg/dL) and erythrocyte sedimentation rate (71 mm/hr) and treatment with 60 mg of oral prednisone daily commenced. He returned to the ED later that night with slurred speech and word-finding difficulties and described seeing cartoon figures and tapestry-like patterns in peripheral vision, which he was aware were not real. Noncontrast computed tomography of the head was normal. Treatment with 1 g of IV methylprednisolone daily for 3 days was initiated. On neuro-ophthalmic examination 3 days later, vision was 20/30 in each eye. Ophthalmoscopy demonstrated bilateral pallid optic disc edema and scattered cotton wool spots (Fig. 1A). Peripapillary optical coherence tomography (OCT) demonstrated confirmed elevation of retinal nerve fiber layer (RNFL) bilaterally (Fig. 1B). Visual fields (Automated 24-2 algorithm) were severely constricted in each eye (Fig. 1C). MRI of the brain and neck with angiography showed near complete occlusion of extracranial Department of Ophthalmology and Vision Science (LD, EM), University of Toronto, Toronto, Canada; and Department of Medicine (EM), Division of Neurology, University of Toronto, Toronto, Canada. The authors report no conflicts of interest. Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 1. A. Pallid edema of the bilateral optic nerves with cotton wool spots indicating both retinal and optic disc head edema. B. Peripapillary OCT demonstrating increase in the RNFL around both optic nerves. C.Automated visual fields (24-2 algorithm) showing diffuse concentric restriction, more severe in the right eye. enhancement of optic nerve sheaths, the radiologic hallmark of perineuritis, it was performed almost a week after treatment with high-dose steroids was initiated that could have caused its resolution (Fig. 2B). GCA can affect any subset of the ocular arterial blood supply, usually with devastating visual consequences. Normal visual acuity, however, does not rule out this diagnosis, and a subset of cases with vision of 20/40 or better has been consistently reported in cohorts of patients with AAION with little attention as to why this occurs (6– 8). In one recent population-based study, 4 of 18 patients with AION due to GCA had a visual acuity of 20/50 or e480 Donaldson and Margolin: J Neuro-Ophthalmol 2022; 42: e479-e481 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 2. A. Postcontrast T1 axial sequence demonstrating concentric enhancement of the right vertebral artery (white arrow) with complete occlusion of the lumen. Postcontrast T1 coronal (B) and axial (C) sequences showing normal signal and lack of enhancement within the body of the optic nerves and optic nerve sheaths. better in at least one affected eye (6), although few details of these cases were provided and no potential mechanism for central vision sparing was discussed. Another series of 37 GCA patients with AION reported 9 cases with vision of 20/40 or better where visual field testing showed diffuse constriction, arcuate, or altitudinal defects (9). There was a trend toward shorter duration of symptoms before presentation in the preserved central acuity group, suggesting they may have earlier disease with incomplete SPCA occlusion. We have previously described 2 cases of GCA with altitudinal defects and normal central vision (10). Both patients had segmental optic disc edema suggesting selective involvement of only a subset of SPCAs. We described a patient with bilateral AION due to GCA with preserved central acuity despite involvement of more than one circulation (inner retinal circulation and SPCAs) and offered potential mechanisms by which central acuity may be spared in AAION. First, there may be incomplete occlusion of the SPCAs, typically in patients with shorter duration of symptoms and in those with visual recovery after steroid treatment (3). Second, only a subset of SPCAs might be involved by vasculitis, which is often associated with segmental disc edema and/or altitudinal or arcuate visual field defects (10). Finally, there may be selective involvement of the small pial vessels producing optic perineuritis (4,5). Although in our case there was no radiographic evidence of perineuritis, orbital MRI was performed 2 weeks after treatment with steroids was initiated that could have resolved all signs of optic nerve sheath enhancement on imaging. As very few patients with GCA undergo a timely contrast-enhanced orbital neuroimaging study, the true incidence of perineuritis secondary to GCA is likely underestimated, particularly in the subset of cases with preserved central acuity. 1. Hayreh SS. Anterior ischaemic optic neuropathy. Differentiation of arteritic from non-arteritic type and its management. Eye (Lond). 1990;4:25–41. 2. Henkind P, Charles N, Pearson J. Histopathology of ischemic optic neuropathy. Am J Ophthalmol. 1970;69:78–90. 3. Kattah JC, Mejico L, Chrousos GA, Zimmerman LE, Manz HJ. Pathologic findings in a steroid-responsive optic nerve infarct in giant-cell arteritis. Neurology. 1999;53:177–180. 4. Purvin V, Kawasaki A, Jacobson DM. Optic perineuritis: clinical and radiographic features. Arch Ophthalmol. 2001;119:1299– 1306. 5. Emami S, Howarth D, Margolin E. Giant cell arteritis presenting as bilateral optic perineuritis in an African man. J Neuroophthalmol. 2020.(epub ahead of print). 6. Chen JJ, Leavitt JA, Fang C, Crowson CS, Matteson EL, Warrington KJ. Evaluating the incidence of arteritic ischemic optic neuropathy and other causes of vision loss from giant cell arteritis. Ophthalmology. 2016;123:1999–2003. 7. Hayreh SS, Podhajsky P. Visual field defects in anterior ischemic optic neuropathy. Doc Ophthalmol Proc Ser. 1979;19:53–71. 8. Liu GT, Glaser JS, Schatz NJ, Smith JL. Visual morbidity in giant cell arteritis. Clinical characteristics and prognosis for vision. Ophthalmology. 1994;101:1779–1785. 9. Antonio-Santos AA, Murad-Kejbou SJ, Foroozan R, Yedavally S, Kaufman DI, Eggenberger ER. Preserved visual acuity in anterior ischemic optic neuropathy secondary to giant cell (temporal) arteritis. J Vasc Interv Neurol. 2016;8:17–21. 10. Donaldson L, Shemesh AA, Margolin E. Two cases of segmental disc oedema and normal visual acuity in giant cell arteritis. Neuroophthalmology. 2018;43:201–204. Donaldson and Margolin: J Neuro-Ophthalmol 2022; 42: e479-e481 e481 STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: L. Donaldson and E. Margolin; b. Acquisition of data: L. Donaldson and E. Margolin; c. Analysis and interpretation of data: L. Donaldson and E. Margolin. Category 2: a. Drafting the article: L. Donaldson and E. Margolin; b. Revising it for intellectual content: L. Donaldson and E. Margolin. Category 3: a. Final approval of the completed article: L. Donaldson and E. Margolin. REFERENCES Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.