Clinical characteristics and treatment approaches in patients with Susac syndrome: a scoping review of cases.

BACKGROUND: Susac syndrome (SuS) is a rare disease characterized by encephalopathy, hearing impairment and visual disturbances. Immunosuppressive treatments are used based on the hypothesis that an autoimmune endotheliopathy drives the disease. However, a solid evidence-based treatment approach is lacking. The aim of this review is to provide an overview of patient characteristics, disease course and treatment patterns related to successful outcome that have been reported in literature since 2013.

METHODS: Three reviewers conducted a systematic literature search in February 2022. The primary outcome was treatment used, derived from cases classified as probable or definite SuS, describing successful treatment outcome (i.e. no signs of disease activity for ≥ 1 month). Secondary outcomes were time-to-relapse and follow-up time. Published case reports and case series were included. Various clinical characteristics and treatment(s) were extracted and categorized into different phases of treatment.

RESULTS: A total of 810 records was identified. 120 articles met inclusion criteria and 161 cases were extracted. Of these, 151 cases were classified as probable or definite SuS and included in the final analysis. Number of combinations of treatments used per treatment phase were: 6 empirically, 35 after confirmed diagnosis, 43 for maintenance treatment, 22 after relapse, 18 during maintenance post-relapse. Median follow-up time was 12.3 months (0.5; 120) and median time to relapse was 4 months (1; 120).

CONCLUSION: This scoping review summarizes treatment approaches in patients with SuS, highlighting variability. International efforts to collect clinical, imaging and treatment data from patients with SuS in registries are needed, in order to provide less biased and long-term follow-up information on treatment response, predictors of relapse and patient outcomes. This may lead to more evidence-based therapeutic approaches.