Paediatric multiple sclerosis: What it is and what it is not

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system of autoimmune origin. Demyelination of the brain, optic nerves and spinal cord causes permanent mental and physical disability. The diagnosis of MS in children, as in adults, requires evidence of dissemination of inflammatory activity in more than one central nervous system (CNS) location (i.e., dissemination in space (DIS)) and recurrent disease over time (i.e. dissemination in time (DIT)). When compared at onset, those diagnosed with MS are more likely to have one or more brain lesions, positive oligoclonal bands, have evidence of remote EBV infection and lower levels of Vitamin D as compared to children with monophasic illness. The identification of myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies and subsequent discovery of their pathogenic mechanisms has led to a paradigm shift in the classification of relapsing demyelinating syndromes. This is reflected in the 2017 revised diagnostic criteria which emphasises the exclusion of MS mimics and aims to enable earlier diagnosis and thus treatment initiation. The long-term efficacy of individual therapies is hard to evaluate due to small patients numbers and to the relatively high number of patients who switch therapy. Nevertheless, an improvement in prognosis with a globally reduced annual relapse rate is observed compared to pre-treatment era. Given the higher relapse rate and concerning cognitive outcomes in children, there is a question whether more rapid escalation or even using more potent agents earlier should be used in children while considering short and long-term safety profile of these drugs. With the results of the first randomised controlled trial of Fingolimod versus Interferon Beta-1a in paediatric MS published this year and several clinical trials underway there is hope for further progress in the field of paediatric MS.