ABSTRACT NUMBER: ESOC2026A2136 LONG-TERM FUNCTIONAL DISABILITY IN SUSAC SYNDROME

Abstract Background and aims Susac syndrome is a rare microangiopathy characterized by encephalopathy, sensorineural hearing loss, and branch retinal artery occlusion. This triad may present sequentially and incompletely, with monophasic, polyphasic, or chronic courses. Treatment relies on immunomodulatory therapy combined with antiplatelet agents; however, prognosis is variable and predictors of unfavorable outcome remain poorly defined. We aimed to assess long-term disability using the modified Rankin Scale (mRS) and identify potential predictors of poor prognosis in Susac syndrome. Methods A retrospective observational study of patients with Susac syndrome followed at a Portuguese tertiary hospital. Demographic data, clinical features, disease activity, treatment, and disability were analyzed. Results Ten patients were included, eight of whom were women, with a median age at onset of 31 years. The maximum time to diagnosis was 4 months, and follow-up ranged from 13 to 230 months. Only four patients presented the complete classical triad. All patients received initial intravenous corticosteroid therapy, combined with human immunoglobulin in seven cases and cyclophosphamide in one. Four patients experienced relapses 1 to 58 months after diagnosis, three of which involved cerebral manifestations. At last follow-up, five patients remained on immunomodulatory therapy, and seven were receiving antiplatelet therapy. Persistent cognitive complaints were reported by nine patients, and two had hearing impairment. Disability assessment showed mRS scores of 1 in five patients, 2 in four patients, and 4 in one patient. Conclusions Despite preserved functional independence in most patients, neurological sequelae, particularly cognitive impairment, are significant. Poorer outcomes appear to be associated with initial neurological involvement and relapses with encephalopathy. Conflict of interest No