Susac syndrome is an autoimmune condition that affects the very small blood vessels in the brain, retina, and inner ear (cochlea). The condition is characterized by three main symptoms: brain disease (encephalopathy), hearing loss, and vision loss. Some people may not have all signs of Susac syndrome, but instead develop only specific combinations of the symptoms. Susac syndrome affects women more than men. The cause of Susac syndrome is still unknown. Diagnosis is based on a clinical exam and imaging tests to look for the specific signs of Susac syndrome.