Flow chart for the diagnosis of MS and its most important differential diagnosis. ADEM acute disseminated encephalomyelitis, CPM central pontine myelinolysis, AHL acute haemorrhagic necrotizing leukoencephalitis; MBD Marchiafava-Bignami disease, MS multiple sclerosis, PML progressive multifocal leukoencephalopathy, RTF Rosenthal fibres, SSPE subacute sclerosing panencephalitis, VWM vanishing white matter disease