First described by American neurologist John Susac in 1979, Susac syndrome (SS) is a rare autoimmune endotheliopathy causing microvascular damage to the brain, retina, and inner ear. As SS progresses it ultimately causes encephalopathy, branched retinal artery occlusion, and hearing loss. The underlying etiology is unknown; however anti-endothelial cell antibodies have been found in 30% of one cohort studied.