Do Not Forget Susac Syndrome in Patients with Unexplained Acute Confusion

Abstract

To report 2 patients with Susac syndrome presenting with acute confusion and abnormal neuroimaging and cerebrospinal fluid (CSF) findings, both of whom were initially misdiagnosed. Susac syndrome is a rare, though likely underdiagnosed, endotheliopathy defined clinically by the triad of encephalopathy, branch retinal artery occlusions (BRAOs), and sensorineural hearing loss (SNHL). Its pathogenesis remains poorly understood. The classic clinical triad may not be fully developed at initial presentation, even at the time magnetic resonance imaging (MRI) demonstrates characteristic central corpus callosum lesions. We describe the patient's clinical course, investigations, management, and follow-up. A 57-year-old woman had acute onset of confusion and was initially thought to have multiple strokes. MRI demonstrated restricted diffusion involving the splenium of the corpus callosum and CSF showed elevated protein levels. Audiometry showed asymmetric bilateral SNHL. Fluorescein angiography showed multiple bilateral BRAOs. Patient received corticosteroids and intravenous immunoglobulin (IVIG). At 1-month follow-up, patient's confusion had resolved. The second patient was a 32-year-old man who had acute onset of confusion. CSF demonstrated pleocytosis and elevated protein. MRI demonstrated restricted diffusion involving the corpus callosum. Patient was discharged and rehospitalized 20 days later where he was diagnosed with acute disseminated encephalomyelitis. Patient presented a third time with vision loss. Fluorescein angiography demonstrated bilateral BRAOs. Audiometry noted bilateral SNHL. He received IVIG and discharged on a prednisone taper and mycophenolate mofetil. At 1-month follow-up, patient's confusion had resolved. We report 2 patients evaluated within 1month of each other who presented with acute confusion and were eventually diagnosed with Susac syndrome. Susac syndrome should be considered in young patients with otherwise unexplained acute onset of confusion with MRI and CSF changes as described previously.