Myelitis is inflammation of the spinal cord. If a patient has acute onset upper and/or lower extremity weakness (7 days or less), do not miss structural cord compression as this is a neurologic emergency. Obtain STAT MRI of the entire spine without contrast. If there is a history of cancer, obtain the MRI with and without contrast to evaluate for epidural mets. If weakness is hyperacute, get MRI with DWI to assess for spinal cord ischemia. If weakness is <48h, also get CTH and CTA head/neck to rule out basilar artery occlusion. If they are diffusely areflexic/hyporeflexic, also do an LP to evaluate for AIDP. You will also need to order telemetry, NIF/FVC q4h, and start IVIG ideally after serum studies collected unless contraindications.