Case Report of Spinal Cord Involvement in Susac Syndrome Masquerading as a Multiple Sclerosis Mimic

We present a unique case of a 59-year-old woman with atypical Susac syndrome and prominent involvement of the spinal cord. She initially presented with progressive headaches, lower extremity weakness and hearing loss. Her MRI brain showed multiple enhancing lesions and her MRI spine showed a T8 enhancing lesion as well as a C2 cord infarct. She was treated with IV methylprednisolone with initial stabilization. However, she developed worsening encephalopathy and lower extremity weakness. Her repeat MRI brain showed new bilateral enhancing lesions and subacute infarcts. Given the increased burden of new lesions, she underwent a brain biopsy, which showed perivascular chronic inflammation within a small vessel distribution. Additionally, fluorescein angiography revealed bilateral branch retinal arterial occlusion (BRAO) and an audiogram demonstrated bilateral sensorineural hearing loss. She was diagnosed with Susac syndrome and treated with IV cyclophosphamide with improvement in her clinical exam. Spinal cord involvement is extremely rare for Susac syndrome, which commonly manifests as the classic triad of encephalopathy, BRAO and hearing loss. Her presentation with myelopathy highlights the importance of considering atypical presentations of well-established syndromes for optimal diagnosis and management.