Demyelination is incorrectly often equated to multiple sclerosis, whereas in reality it is a generic pathological term simply describing, as the word suggests, the loss of normal myelin around axons in the central nervous system. This should be distinguished from dysmyelination where the formation of normal myelin is absent.
Primary demyelinating disorders include:
clinically isolated syndrome (CIS) first symptomatic episode which may or may not progress to MS multiple sclerosis can only be diagnosed if McDonald diagnostic Criteria for MS (or other similar criteria) are met. variants include tumefactive multiple sclerosis acute malignant Marburg type Devic disease (aka Devic opticomyelitis) Schilder type (diffuse cerebral sclerosis) Balo concentric sclerosis (BCS) acute disseminated encephalomyelitis (ADEM) monophasic usually post viral acute demyelination often considered a secondary form of demyelination transverse myelitis chronic inflammatory demyelinating polyneuropathy (CIDP) Guillain-Barre Syndrome
progressive multifocal leukoencephalopathy (PML) HIV encephalitis / HIV dementia complex / HIV associated myelopathy progressive rubella panencephalitis In most cases toxic and metabolic disease which affect the white matter are considered separately but for the sake of completeness they are listed below.
central pontine myelinolysis (CPM) posterior reversible encephalopathy syndrome (PRES) : related to hypertension predominantly chemotherapy
Metabolic / genetic
leukodystrophies adrenoleukodystrophy Krabbe leukodystrophy metachromatic leukodystrophy sometimes classified as leukodystrohpies
Alexander disease Canavan disease Cockayne syndrome Pelizaeus-Merzbacher disease Ischaemia
Although not referred to as demyelination many processes which cause iscahemia lead to demyelination:
deep white matter ischaemia radiotherapy changes