Demyelinating Diseases. Done by:. Mohâ€™d Sulaiman Al-Houqani Mohâ€™d Ali Al-Ali. Introduction. Demyelinating disorders of the CNS affect . myelin. and/or oligodendroglia. with relative sparing of axons.
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Moh’d Sulaiman Al-Houqani
Moh’d Ali Al-Ali
Demyelinating disorders of the CNS affect
with relative sparing of axons.
Oligodendrocytes, like Schwann cells in the peripheral nervous system, are responsible for the formation of myelin around CNS axons.
One Schwann cell myelinates one axons but one oligodendrocyte may myelinate several contiguous axons, and the close proximity of cell to axon may not be obvious by light microscopy.
Oligodendrocyte are present in gray matter near neural cell bodies and in white matter near axons.
Myelin is composed of protein 20% & lipids.
A- Chronic relapsing encephalomyelopathic form.
B- Acute multiple sclerosis.
C- Neuromyelitis optica.
Diffuse cerebral sclerosis (encephalitis periaxalis diffuse) or Schilder and concentric sclerosis of Balo.
Acute disseminated encephalomyelitis.
A- Following measles, rubella & influenza.
B- Following rabies or smallpox vaccination.
Acute and subacute necrotizing hemorrhagic encephalitis.
A- Acute encephalopathic form (hemorrhagic leukoencephalitis of Hurst)
B- Subacute necrotic myelopathy
C- Acute brain purpura(acute pericapillary encephalorrhagia)
MS referred by the British as disseminated sclerosis & by French as Sclerose en plaques.
MS is a common demyelinating disease, characterized by focal disturbance of function and a relapsing and remitting course.
Higher incidence of the disease found in the northern most latitude of the northern & southern hemispheres compared to southernmost latitudes.
MS usually occur in young adults with a peak age incidence of 20-40 years.
more female than males are affected.
The risk of MS in relative patients increases 20 folds.
These lesions have a predilection for the following sites within the brain & SC.:
Environmental Exposure (Virus)
Autoimmune attack by CD4 T-cell
1- Acute MS
No diagnostic test. Only support the clinical suspicion.
Neuropsychological measurement of conduction within the CNS to detect second a symptomatic lesion.:
MRI is more sensitive showing white matter disease.
On T-2 weighted images, patchy area of abnormal white matter are found most commonly in cerebral hemisphere in paraventicular areas; often lesions can be present in the cerebellum , brain stem, cervical and or thoracic spinal cord
Area of demyelination in cerebral hemisphere
MRI finding are not necessarily diagnostic
Anti-inflammatory & immunpsuppressive therapy:
Enhancement of cell mediated immunity