Two Cases of Susac Syndrome Mimicking Multiple Sclerosis.

Objective: To report two patients with Susac syndrome (SS) mimicking Multiple Sclerosis (MS). It’s important to diagnosed Susac syndrome (SS) as there are several differential diagnoses including MS, Acute Disseminated Encephalomyelitis, Systemic Lupus Erythematosus. Background: Case 1: A 27 year old woman presented with cognitive changes and hearing loss. MRI brain showed discrete snowball-like lesions in the corpus callosum. Ophthalmologic evaluation revealed bilateral retinal artery occlusions. Case 2: A 50 year old woman developed hearing loss, gait imbalance and progressive confusion over three weeks. MRI revealed multiple bilateral punctate lesions, some in the corpus callosum. Lumbar puncture (LP) revealed elevated protein. She was treated with intravenous methylprednisolone and intravenous immune globulin (IVIG) with clinical and radiographic improvement. Both patients remained clinically and radiographically stable on maintenance immunomodulating therapy (Mycophenolate and Azathioprine, respectively). Design/Methods: Information regarding patients obtained via retrospective review of electronic medical records. Results: Both patients had extensive evaluations including LP with elevated protein and negative MS markers. Serum studies included negative antinuclear antibody, anti-nuclear cytoplasmic antibody, extractable nuclear antigen panel, homocysteine, and anti-cardiolipin antibody. Fluorescein angiogram revealed multiple branch retinal artery occlusions, further supporting a diagnosis of SS. Conclusions: Susac syndrome is an immune-mediated vasculopathy involving small vessels in the brain, eye, and ear. Classic clinical triad consists of hearing loss, vision changes, and encephalopathy. Imaging findings in SS can be mistakenly identified as demyelinating lesions, and there are reports of patients with SS erroneously being treated for MS. Red flags raising concern for SS include hearing loss, branch retinal artery occlusions, and corpus callosum lesions. Early diagnosis of SS is important with excellent prognosis if treated aggressively at an early stage of the disease. Disclosure: Dr. Sriwastava has nothing to disclose. Dr. Ward has nothing to disclose. Dr. Rajamani has nothing to disclose.