Susac syndrome
Susac syndrome is a microangiopathy of unclear etiology causing encephalopathy (corpus callosum involvement is prominent), branch retinal artery occlusions (BRAOs), and sensorineural hearing loss (SNHL). Headache can be a prominent feature (seen in >75% of patients). The disease commonly affects young women (80%) aged 15 to 40 years, with no racial predilection. Diagnosis is based on characteristic clinical features and MRI findings and is made challenging by the fact that <20% of patients present with simultaneous involvement of the classic triad of clinical features.
The treatment regimen in the acute setting includes high-dose corticosteroids (3-day pulse therapy of solumedrol 1000 mg/day followed by prednisone 1 mg/kg for 2 to 4 weeks with subsequent taper) and consideration of intravenous immunoglobulin therapy. Corticosteroid-sparing immunosuppressive therapies that have been used include mycophenolate mofetil, rituximab, cyclophosphamide, azathioprine, and cyclosporine. Plasmapheresis has been described in the acute setting as well. Some experts recommend the addition of aspirin to reduce the risk of small-vessel thrombosis. Unfortunately, hearing and visual field loss suffered at the time of diagnosis is irreversible, and treatment is instituted to prevent further loss.
