Differential Diagnosis of Transverse Myelitis Maureen A. Mealy, RN, BSN, Daniel Becker MD, Scott D. Newsome, DO, John N. Ratchford, MD, Michael Levy, MD, PhD, Carlos A. Pardo, MD The Johns Hopkins Transverse Myelitis Center performed a retrospective analysis to determine the true spectrum of diagnoses of those patients referred to and seen for the presumed diagnosis of TM at the time of referral. As you know, TM is a non-specific inflammatory attack of the spinal cord. The common causes include monophasic idiopathic transverse myelitis (ITM), multiple sclerosis (MS), neuromyelitis optica (NMO) and rheumatologic diseases. The JHTMC is dedicated to the diagnosis and management of TM, and to other conditions that can mimic TM. We reviewed 591 patients who presented between August 2010 and July 2013. The final diagnoses were based on clinical profiles, neuroimaging, and the specific diagnostic criteria for each disease or condition for which patients were eventually diagnosed after extensive work-ups were completed. The goal was to report the full differential diagnosis of TM, including non-inflammatory causes. This research was made possible because of the generosity and support of Johns Hopkins Project RESTORE, the Bart McLean Fund for Neuroimmunology Research, and most especially the patients of the Johns Hopkins Transverse Myelitis Center. Two-thirds of patients referred to the JHTMC had inflammatory TM. However 26% of patients initially diagnosed with TM did not have inflammatory myelitis, 5% of whom did not have myelopathy at all. The findings suggest that a portion of patients diagnosed with TM may have other non-inflammatory causes of myelopathies that deserve a more detailed evaluation.