Fulminant demyelinating diseases of the central nervous system include acute disseminated encephalomyelitis, the related acute hemorrhagic leukoencephalitis, multiple sclerosis variants, neuromyelitis optica spectrum disorders, and idiopathic transverse myelitis. These syndromes are often managed with similar acute treatments including high-dose corticosteroids and plasmapheresis; however, long-term management varies. Although the prognosis of fulminant demyelinating disease was historically poor, outcomes today may be improved due to earlier diagnosis, rapid implementation of anti-inflammatory therapies such as high-dose corticosteroids and plasmapheresis, and improved supportive care.