Transverse myelitis (TM) is a serious inflammatory disorder of the spinal cord. The annual incidence is 1 to 5 cases per million people. It produces sensory, motor and autonomic symptoms. Once metabolic and vascular causes and demyelinating diseases have been ruled out, they can be classified as paraneoplastic, parainfectious (up to half debut after infection), toxic-pharmacological (TNFα receptor inhibitors can induce TM) or associated with systemic diseases (Lupus). After a complete study, up to 30 % are considered idiopathic.