Snapshot A 35-year-old woman presents to the emergency department with severe bilateral eye pain. She said that her vision acutely worsened over the course of the day and has experienced eye pain, especially with movements. Her symptoms are associated with mild lower extremity weakness and she endorses having urinary incontinence. Physical examination is notable for 3+ patellar reflexes with 4-/5 power in her bilateral lower extremities. An MRI brain and spine demonstrate signal intensities in the optic nerves and the lumbothoracic spine. She is immediately started on high-dose intravenous methylprednisolone. She is admitted to the hospital and was found to have positive AQP4-IgG antibodies. Introduction Definition a central nervous system inflammatory and demyelinating disorder that predominantly affects the optic nerve and the spinal cord Associated conditions other autoimmune disorders (e.g., sarcoidosis) Epidemiology Incidence more common in women Etiology Idiopathic Pathogenesis Probably secondary to B-cell autoimmunity to aquaporin-4 (AQP4) aquaporin-4 is found in the astrocyte end-feet Presentation Symptoms/physical exam optic neuritis login to view 2 more bullets transverse myelitis login to view 3 more bullets intractable hiccups, nausea, or vomiting login to view 1 more bullet Imaging MRI brain indication login to view 1 more bullet findings login to view 6 more bullets Studies Serum presence of AQP4-IgG antibodies Differential Multiple sclerosis differentiating factors login to view 4 more bullets Treatment Medical methylprednisolone login to view 2 more bullets long-term immunosuppression login to view 6 more bullets Complications Neurogenic respiratory failure