Overview
Definition
An immune-mediated inflammatory disease that attacks myelinated axons in the central nervous system (CNS), destroying the myelin and the axon in variable degrees.
Epidemiology
Most commonly diagnosed in young adults (20-40 years), with a strong female predominance. Higher prevalence further from the equator.
Etiology & Risk Factors
- Autoimmune destruction of CNS myelin and oligodendrocytes. Mediated by T-cells and B-cells. Trigger is unknown (EBV infection and Vitamin D deficiency are suspected risk factors).
Clinical Symptoms
- Optic neuritis (painful monocular vision loss, afferent pupillary defect)
- Internuclear ophthalmoplegia (MLF lesion: impaired adduction on affected side with nystagmus of abducting eye)
- Sensory abnormalities (numbness, tingling, Lhermitte's sign - electric shock down spine on neck flexion)
- Motor weakness, spasticity, ataxia
- Bowel/bladder dysfunction
Clinical Approach
Diagnosis
- MRI Brain and Cervical/Thoracic Spine with contrast: Demyelinating plaques (Dawson fingers) separated in space (multiple areas) and time (some enhancing, some non-enhancing)
- Lumbar Puncture: Oligoclonal IgG bands in CSF (not in serum)
Management
- Acute exacerbations: High-dose IV Corticosteroids (Methylprednisolone)
- Disease-Modifying Therapies (DMTs) to slow progression: Ocrelizumab (Anti-CD20), Natalizumab, Interferon beta, Glatiramer acetate
- Symptomatic treatment: Baclofen (spasticity), Oxybutynin (urinary symptoms)
Complications
- Progressive disability (Secondary progressive MS)
- Severe depression/cognitive impairment
- Infections (due to immunosuppressive therapies)