In contrast, infarcts, contusions, encephalitis and other conditions destroy myelin and axons equally. Both these are autoimmune inflammatory diseases. There are also virus-induced demyelinative diseases. Demyelinative diseases should be distinguished from leukodystrophies, which are inherited metabolic disorders of myelin lipids.
Some cases are progressive from the start or go into a progressive phase later.
The pathology of MS develops around blood vessels. In most cases, the inflammatory reaction subsides only to appear at another location or at another time. Some lesions expand at their periphery while activity in their center subsides. The pathological process may be arrested at any time, sometimes after partial demyelination. Macrophages remove damaged myelin.