The pathology of multiple sclerosis and related disorders

The histopathology of multiple sclerosis (MS), the most common demyelinating disorder, is the main focus of this review. MS is characterized by inflammatory demyelination, accompanied by gliosis. The MS plaque can show ongoing active demyelination, which can be accompanied by varying degrees of remyelination, or be quiescent. The current concept that MS is an autoimmune disease of myelin has been challenged by recent studies, and it is becoming increasingly clear that neurodegeneration is a significant component of the disease and may largely account for its progressive disability. Other disorders related to MS that are briefly discussed here are acute disseminated encephalomyelitis, acute haemorrhagic leucoencephalitis, neuromyelitis optica and progressive multifocal leucoencephalopathy.