OMG and Posterior Leukoencephalopathy Syndrome: However, in cases with rapidly progressive white matter changes, acute/subacute processes should be considered including acute disseminated encephalomyelitis, acute demyelinating disease such as neuromyelitis optic (NMO) spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), infectious etiologies, toxic/metabolic etiologies, autoimmune and paraneoplastic etiologies, posterior reversible encephalopathy syndrome, vasculitis, and adult-onset leukodystrophy.