most common myelin disorder

chronic degenerative disease of the CNS characterized by demyelination and axonal degeneration in the brain and spinal cord, which are caused by an immune-mediated inflammatory process.

There is a variety of types of MS—relapsing remitting (most common), secondary progressive, progressive relapsing, and primary progressive —together with ‘benign’ and ‘malignant’ forms.

Demographics

• Common 1:1000
• young adults 20-50y
• females 2:1

Aetiology

• Autoimmune (Gen+Env+AI)
  • genetic: twins, family HLA DR2,
  • environment: Virus, EBV?
  • autoimmune: TH1 & TH17

Risk Factors

• Genetic predisposition: Presence of HLA-DRB1*15 allele increases the risk of MS
• Environmental risk factors
  • Low vitamin D levels (insufficient intake, decreased exposure to UV radiation)
  • Cigarette smoking
  • Pathogens: EBV, HHV 6
  • Obesity early in life

Clinical Features

Manifests in a relapsing-remitting form characterized by episodic CNS dysfunction (exacerbations) with at least partial recovery between episodes.

Presentation and course are highly variable and unpredictable. Affects different areas of the central nervous system, simultaneously or sequentially. The locations of the plagues will determine the symptoms

• attacks of remission & relapses of Limb Weakness, paraesthesia, vision abnormalities