A Multicentre randomiSed Controlled TRial of IntraVEnous Immunoglobulin Versus Standard Therapy for Transverse Myelitis

Inclusion Criteria: * Diagnosis of EITHER acute first onset transverse myelitis (using the TM Consortium Working Group 2002 criteria) - patients must fulfill all of the following criteria: * Sensory, motor, or autonomic dysfunction attributable to spinal cord disease * Bilateral signs and/or symptoms (not necessarily symmetric) * Sensory level (except in young children \<5 years where this is difficult to evaluate) * Lack of MRI brain criteria consistent with multiple sclerosis * Progression to nadir between 4 h and 21 days OR first presentation of neuromyelitis optica (using standardised criteria) - patients must fulfil both absolute criteria: * Optic neuritis * Acute myelitis, plus two out of three supportive criteria (as Aquaporin 4 antibody (AQP4) is often not available acutely, only the first two supportive criteria would be applied), * Brain MRI not meeting criteria for Multiple Sclerosis (MS) at disease onset * Spinal cord MRI with contiguous T2-weighted signal abnormality extending over three or more vertebral segments, indicating a relatively large lesion in the spinal cord * AQP4 seropositive status * ASIA Impairment Score of A-C * Randomisation to occur no later than day 5 of steroids, and, if definitely known, within 21 days from symptom onset. * Give assent (8-16 years)/consent to participate in the trial Exclusion Criteria: * Contraindication to IVIG as stated in the summary of product characteristics (SmPC), or receiving IVIG for other reasons * Previously known systemic autoimmune disease (e.g. systemic lupus erythematosus) or any evidence of systemic inflammation during current presentation. * Direct infectious aetiology (e.g. varicella zoster) * Previous episode of central nervous system (CNS) inflammatory demyelination * Acute disseminated encephalomyelitis (ADEM) * Other causes of myelopathy not thought to be due to myelitis (e.g. nutritional, ischaemic, tumour etc.) * Other disease which would interfere with assessment of outcome measures * Known pregnancy * Circumstances which would prevent follow-up for 12 month