Susac syndrome with the typical clinical triad: A case report and literature review.

Susac syndrome is an immune-mediated microvascular disease characterized by the clinical triad of acute multiple encephalopathies, branch retinal artery occlusion, and sensorineural hearing loss. However, the typical clinical triad is not seen in all patients at disease onset. In this study, a 29-year-old male was admitted to our hospital due to aggravation of headache accompanied by retarded reaction. After treatment for a diagnosis of possible central nervous system vasculitis, the patient's retarded reaction and neurological dysfunction were improved. One year after discharge, the patient had no abnormal clinical symptoms and he discontinued taking prednisone voluntarily five months after discharge. Two years later, the patient was admitted to our hospital again owing to a sudden visual field defect in the superonasal quadrant of the left eye for one week, and Susac syndrome was diagnosed. After treatment, the patient's condition became stabilized with no further progress, but the visual field defect did not recover. At the onset of Susac syndrome, the typical clinical triad of Susac syndrome is rare, so this disease is difficult to be recognized at the beginning. The case we report presented the clinical triad two years after the disease onset. We expect that this case report will increase physicians' understanding of Susac syndrome.