Susac Syndrome (SS) is a rare autoimmune endotheliopathy that affects the brain, retina, and eye in older patients. We describe a case of encephalopathy in pediatrics that was initially diagnosed with ADEM. After a thorough evaluation, the patient was officially diagnosed with SS. 

 A 16-year-old female with a history of idiopathic generalized epilepsy (on Levetiracetam), depression, and migraines presented with altered mental status preceded by left ear tinnitus and hearing loss. MOG (Myelin oligodendrocytes), and AQP4 (aquaporin 4) antibodies and oligoclonal bands were negative. EEG was within normal limits. MRI showed (Multiple T2 hyperintense cerebral white matter foci in the cerebellum, anterior right corpus callosum, splenium of corpus callosum, and midline). An MRA brain could not rule out microscopic vasculitis. IVIG (Intravenous immunoglobulin) and high-dose steroids were started for presumed ADEM versus vasculitis versus multiple sclerosis versus SS. 

 Eye exam revealed a right intraretinal hemorrhage along the sup arcade above the macula. The hearing test confirmed bilateral SNHL. By the time of discharge, she was back to her baseline and had significant improvement in her gait. On the following relapse, 4 months later, she was confirmed to have bilateral retinal artery occlusion. She was officially diagnosed with SS and was started on immunomodulating treatment with IVIG and Rituximab. She has been symptoms free for 2 years now. 

This case highlights the importance of broadening differential diagnosis of encephalopathy of neurological etiologies in pediatrics. Early consideration of SS and knowing the diagnostic criteria are crucial as it has a different treatment approach and prognosis of other disorders.