脱髓鞘幻灯2009医大.pptx

The commonest accepted the pathologic criteria of demyelinative disease in CNS:
1. Destruction of the myelin sheaths of nerve fibers;
2. Relative sparing of other elements of nervous tissue, . of axis cylinders, nerve cell, and supporting structure, and a relative lack of Wallerian, or secondary, degeneration off fiber tracts.
3. A particular distribution of lesions often is perivenous and primarily in white matter.
Classification of demyelination disease in CNS
Dysmyelinative type (leukodystrophy)
It results from failure to form normally constituted myelin, due to genetic enzymatic disorders, such as adrenoleukodystrophy (ADL), Globod leucodystrophy (Krabbe), Metachromatic leucodystrophy (MLD)
Demyelinating type
It is breakdown of normally constituted myelin.
Classifications of the demyelination disease
Multiple sclerosis
1. relapsing-remitting , RR
2. primary progressive, PP
3. secondary progressive, SP
4. progressive relapsing , PR
Neuromyelitis optica (Devic)
Diffuse cerebral sclerosis (Schilder) & concentric sclerosis of Balo
Acute disseminated encephalomyelitis
Central pontine myelinnolysis
Multiple sclerosis
Multiple sclerosis is the most common demyelinating disorder. It is a disease of the central white matter with “ lesions separated in time and space”. Generally, MS is characterized clinically by remitting - relapsing course.
The disease usually occurs in young adults. The peak age of onset is 20-40 and 95% patients occurs between 10-60 years.
More females than males are affected.
Etiology and pathogenesis
1. Geographical influence:
Populations residing between tropical and subtropical zones have a low risk of MS. All populations residing this latitudes in North America and Europe are higher risk.
2. Familial factors:
It was found that almost 20% of index cases had an affected relative, again with the highest risk in siblings in a large population study in British.
studies of twins
histocompatibility