AB1855 SUSAC SYNDROME: CASE SERIES FROM ADULT & PEDIATRIC TERTIARY ACADEMIC MEDICAL CENTERS

Background Susac Syndrome (SS) is a rare autoimmune endotheliopathy that affects the brain, retina, and inner ear, characterized by clinical triad of encephalopathy, branch retinal artery occlusion (BRAO), sensorineural hearing loss (SNHL) [1] . Brain MRI, fluorescein angiogram (FA), audiometry help to establish diagnosis [2] The presentation SS often variable leading delay in diagnosis. Objectives This study aims compare features therapeutic strategies adult pediatric populations with Syndrome. Methods was retrospective chart review cases from December 2010 2020 at Ohio State University Wexner Medical Center (OSUWMC) Nationwide Children’s Hospital Columbus, Ohio, USA (tertiary care centers). We analyzed following: age, gender, ethnicity, symptoms time presentation, diagnostic studies, serologies, brain FA, audiometry, treatment approaches, outcomes. Results All patients (seven adult- two pediatric-onset patients) identified as females, majority (78%) were Caucasian. age ranged 10 45 years old mean 38 years. 3 17 months 7.8 months. most common onset included dizziness, loss, visual change. ESR elevated 50% range 23 52 mm/hr (normal<30 mm/hr). CRP 22% 11 22 mg/dl (normal <10 mg/dL). Low medium titer ANA positive 30%. FA detected unilateral or bilateral BRAO seven (78%). Sensorineural confirmed on audiogram testing 7 9 patients, 44% had loss. 88% our patient population evidence corpus callosal involvement (“snowball lesions”) MRI. CSF done 5 - 4/5 protein 77 mg/dL (range 15-45 mg/dL) cell count <3 (normal), without any oligoclonal bands. One biopsy. initial high-dose steroids followed taper. Oral immunosuppressive therapy mycophenolate mofetil (MMF) initiated 78% maintained 56% who remained stable. Intravenous immunoglobulin (IVIG) initially used patients. Two transitioned MMF azathioprine due pregnancy. Due severity disease, one tacrolimus Rituximab. 20% disease flare after requiring additional immunosuppression. Conclusion Our series highlights rarity SS. A neurologic exam, angiogram, should be performed every case. biopsy not necessary for diagnosis, unless exclusion. 75% highlighting importance an ophthalmology evaluation even absence symptoms. In series, only presented full visual, auditory, central nervous system symptoms, indicating incomplete relies high index suspicion [3] Treatment depends involves use corticosteroids along immunosuppression including mycophenolate, IVIG, tacrolimus, rituximab, cyclophosphamide [4] References Rennebohm R, JO, Egan RA, Daroff RB. Susac’s Syndrome--update. Journal neurological sciences 2010; 299 (1-2): 86-91. Kleffner I, Dörr J, Ringelstein M, et al. Diagnostic criteria syndrome. neurology, neurosurgery, psychiatry 2016; 87 (12): 1287-95. Krautwald S, Wildemann B, Characteristics syndrome: all reported cases. Nature reviews Neurology 2013; (6): 307-16. RM, Asdaghi N, Srivastava Gertner E. Guidelines syndrome An update. International journal stroke: official Stroke Society 2020; 15 (5): 484-94. Acknowledgements project described supported Award Number UL1TR002733 National Advancing Translational Sciences. content solely responsibility authors does necessarily represent views Sciences Institutes Health. have no conflict interest disclose. Disclosure Interests None Declared.