Serial retinal fluorescein angiography and immune therapy in Susac's syndrome.

We report a patient with Susac's disease presenting classically in a young female with an encephalopathy and visual disturbance with later deafness and tinnitus. Her encephalopathy settled, but subsequent serial fluorescein angiograms allowed sensitive monitoring of continuing sub-clinical disease activity, and provide evidence of a clear therapeutic response to immune suppression with tacrolimus (but not steroids alone)--and of a lack of efficacy of nimodipine and aspirin. We believe this single case study has both pathogenetic and useful practical implications: the apparently favourable response to immunosuppression lends support to the hypothesis that Susac's Syndrome is an immune-mediated disease; while the presence during symptomatic clinical remission of sporadic, multi-focal episodes of hyper-fluorescence, suggestive of breakthrough vasculopathy despite treatment, underlines the fact that the natural history of this rare condition is still not fully understood. Fluorescein angiography is proposed as a sensitive and important approach to the monitoring of sub-clinical disease activity, and so optimising immune suppressive treatment.