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Case A woman in her 30s presented with 3 weeks of distorted vision in her right eye and a visual field defect in the left eye. This was her first episode, and she denied any pain. Visual acuity was 20/25 + 2 OD and 20/20 OS. Confrontation visual fields detected a superior field defect in the left eye. Pupils, intraocular pressures, and anterior segment examination results were within normal limits. Dilated fundus examination revealed whitening and attenuation of a small arteriole in the inferior arcade of the right eye (Figure, A). Examination of the left eye revealed an inferior branch retinal artery occlusion and a patch of retinal whitening superior to the optic disc approximately one-third disc diameter in size (Figure, B). No Hollenhorst plaques were identified. Fluorescein angiography demonstrated segments of arteriole hyperfluorescence with distal nonperfusion in both eyes (Figure, C). This hyperfluorescence and nonperfusion occurred within straight arteriole segments, not at arteriole bifurcations. The differential diagnosis included systemic lupus erythematosis, polyarteritis nodosa, Behçet disease, granulomatosis with polyangiitis (Wegener disease), acute retinal necrosis, syphilis, and hypercoagulability. An outpatient workup composed of fluorescent treponemal antibody absorption, QuantiFERON–TB Gold (Quest Diagnostics), erythrocyte sedimentation rate, antinuclear antibody, complete blood cell count, prothrombin time, and partial thromboplastin time was ordered. Figure. View LargeDownload A, Fundus photograph of the right eye shows subtle whitening and attenuation of an arteriole. B, Left eye illustrates an inferior branch retinal artery occlusion and retinal whitening superior to the optic disc. C, Fluorescein angiography demonstrates hyperfluorescence of an arterial midsegment with distal nonperfusion. The next day, the patient developed severe headaches and presented to the local emergency department. She retained normal sensorium but had decreased hearing bilaterally. Box Section Ref ID What Would You Do Next? Consult otolaryngology for hearing evaluation Order an echocardiogram Order brain magnetic resonance imaging Order carotid ultrasonography Read the Discussion. Discussion Diagnosis Susac syndrome What To Do Next C. Order brain magnetic resonance imaging Discussion Magnetic resonance imaging of the brain with gadolinium was performed and revealed multifocal white matter lesions in the corpus callosum that were best seen on sagittal T2 images. Given the constellation of branch retinal artery occlusion, severe headache, and auditory changes, this was diagnostic for Susac syndrome. Vasculitic workup findings were negative for other causes. Susac syndrome is a rare disorder of the retinal, cochlear, and cerebral microvasculature, with 300 reported cases since its description in 1973.1 Classically defined as a triad of encephalopathy, retinal artery occlusions, and sensorineural hearing loss, it has a predilection for women (3:1) particularly between ages 20 and 40 years. Headache is the most common presenting symptom, occurring in approximately 78% of people.1 Central nervous system involvement manifests as psychiatric disturbances, confusion, and dementia. These symptoms may unfold over weeks to months. Forty percent of cases have evidence of retinal arteritis; however, this increases to 97% throughout the course of disease.1 The prolonged time course, varying neurologic symptoms, and often vague visual symptoms lend Susac syndrome to misdiagnosis. This patient falls into the subset of cases with ophthalmic disease as the initial symptom. This disease is thought to derive from immune-mediated endothelial injury of small arterioles less than 100 µm in diameter as histopathology demonstrates endothelial cell necrosis and anti–endothelial cell antibodies.2 Humoral autoimmunity may take part in the pathogenesis as antiendothelial cell IgG1 and IgM antibodies have been detected in some affected patients.3 However, there are no recommendations for the routine use of these serological tests. All patients with suspected Susac syndrome should receive fluorescein angiography, as it may detect subtle microangiopathy not seen on examination. Egan et al4 suggested that segments of arterial hyperfluorescence represent focal endotheliopathy, which may be invisible on examination, in contrast to other vasculitides. Yellow arterial plaques, called Gass plaques, may develop from lipid leakage from chronically damaged vessel walls. Gass plaques are found distant from arterial bifurcations in contrast to Hollenhorst plaques. Echocardiogram and carotid ultrasonography are unnecessary as these findings are not embolic in nature. Brain magnetic resonance imaging is of utmost importance and should not be delayed by such testing as audiometry. In the context of encephalopathy, corpus callosal lesions are pathognomonic for Susac syndrome, as the diagnosis can be made even without retinal artery occlusions or auditory changes.5 Often called snowballs, these microinfarctions are best seen on sagittal T2 fluid-attenuated inversion recovery sequences. Microinfarctions affecting the internal capsule may also give a string-of-pearls appearance on diffusion-weighted imaging. Corticosteroids, methotrexate, mycophenolate mofetil, azathiopurine, intravenous immunoglobulin, and plasmapheresis have been used to manage this condition.6 The low incidence of this condition and lack of controlled studies limit the ability to create definitive treatment guidelines. Patient Outcome In this patient, systemic steroids were initiated and her symptoms improved. Her visual acuity returned to 20/20 OU but she retained the superior visual field defect. Back to top Article Information Corresponding Author: Sunir J. Garg, MD, Mid-Atlantic Retina, The Retina Service of Wills Eye Hospital, 840 Walnut St, Ste 1020, Philadelphia, PA 19107 (firstname.lastname@example.org). Published Online: March 10, 2016. doi:10.1001/jamaophthalmol.2015.3628. Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported. References 1. Dörr J, Krautwald S, Wildemann B, et al. Characteristics of Susac syndrome: a review of all reported cases. Nat Rev Neurol. 2013;9(6):307-316.PubMedGoogle ScholarCrossref 2. Magro CM, Poe JC, Lubow M, Susac JO. Susac syndrome: an organ-specific autoimmune endotheliopathy syndrome associated with anti-endothelial cell antibodies. Am J Clin Pathol. 2011;136(6):903-912.PubMedGoogle ScholarCrossref 3. Jarius S, Kleffner I, Dörr JM, et al. Clinical, paraclinical and serological findings in Susac syndrome: an international multicenter study. J Neuroinflammation. 2014;11:46.PubMedGoogle ScholarCrossref 4. Egan RA, Hills WL, Susac JO. Gass plaques and fluorescein leakage in Susac syndrome. J Neurol Sci. 2010;299(1-2):97-100.PubMedGoogle ScholarCrossref 5. Rennebohm R, Susac JO, Egan RA, Daroff RB. Susac’s syndrome: update. J Neurol Sci. 2010;299(1-2):86-91.PubMedGoogle ScholarCrossref 6. Bitra RK, Eggenberger E. Review of Susac syndrome. Curr Opin Ophthalmol. 2011;22(6):472-476.PubMedGoogle ScholarCrossref
JAMA Ophthalmology – American Medical Association
Published: May 1, 2016
Keywords: headache,diagnostic techniques, ophthalmological,retinal artery occlusion,scotoma,vision disorders,visual field defects,brain mri,young adult,eye,vision
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