Susac Syndrome: an uncommon cause of impaired vision

A 35-year-old Caucasian woman presented an abrupt onset of bilateral impaired vision, and arrived to our attention two weeks later. She had a previous episode of mild dizziness. She underwent a fluorescein angiography showing branch retinal artery occlusions and a brain magnetic resonance imaging (MRI) revealing several supraand infratentorial FLAIR-hyperintense white matter lesions, two with contrast enhancement. Thrombophilic, autoimmune and infective (including Human Immunodeficiency Virus, Borrelia burgdorferi, Hepatitis B Virus, Hepatitis C Virus, Herpes Simplex Virus 1-2, Varicella Zoster Virus) screening was negative. Cerebrospinal fluid analysis showed intrathecal IgG synthesis. We suspected a Primary Central Nervous System Vasculitis, and intravenous steroids were started. Three months later a second brain MRI showed seven new lesions without contrast enhancement, and she revealed a cognitive impairment and bilateral hearing loss. Reviewing the clinical history and MRI, she fulfilled diagnostic criteria for Susac syndrome. She had two cycles of cyclophosphamide, and recovered in 6 months and then remained stable with metotrexate.