Susac Syndrome Successfully Treated with Mycophenolate Mofetile

Background: Susac Syndrome is an infrequent condition that is often misdiagnosed as Multiple Sclerosis. This syndrome is characterized by the clinical trial of encephalopathy, retinopathy with branch retinal artery occlusions and hearing loss. Methods: We describe a patient with Susac Syndrome that was initially diagnosed as having multiple sclerosis with clinical deterioration after starting treatment with interferon beta-1a. Results: Despite the classic triad of encephalopathy, branch retinal occlusions and hearing loss is pathognomonic of Susac Syndrome, it is present in only a small percentage of patients. In our case, at the onset of symptoms the triad was incomplete and thus the correct diagnosis and treatment were delayed. Although the clinical trial was incomplete, our patient had the classic magnetic resonance appearance with branch retinal artery occlusions and sensorineural hearing loss. The cerebrospinal fluid examination was normal with no oligoclonal bands and a no elevated IgG index. Our patient responded well to the correct immunosuppressive treatment, with clinical improvement. The lesions in the magnetic resonance also improved after the treatment. Conclusions: Susac syndrome must be considered in the differential diagnosis of MS, especially in cases with suggestive symptoms, lesions involving corpus callosum, no oligoclonal bands in LCR and in patients with progressive worsening despite a correct DMT. A prompt diagnosis is essential in order to prevent disability or irreversible sequelae related to the disease.