Overview
This lecture gives a concise explanation of multiple sclerosis (MS), its symptoms, causes, underlying pathology, and current treatment strategies.
What is Multiple Sclerosis (MS)?
- MS is a central nervous system disorder marked by sudden neurological symptoms.
- Symptoms usually first appear between ages 20 and 50.
- Symptoms vary but often include visual disturbances, abnormal sensations, and muscle weakness.
Causes and Risk Factors
- The exact cause of MS is unknown.
- Both genetic and environmental factors are believed to contribute.
Pathology of MS
- MS is characterized by damage to myelin sheaths around axons in the CNS (central nervous system).
- Myelin damage disrupts the conduction of action potentials, leading to symptoms.
- Damage may also deteriorate axons themselves.
- Plaques or lesions from myelin loss are visible in MS brains through neuroimaging.
Immune System Involvement
- MS is widely thought to result from an autoimmune attack where the immune system targets myelin.
- This immune response causes inflammation and damage to myelin, axons, and glial cells.
- The trigger for the autoimmune response is unknown; a persistent infection has also been proposed.
- Excessive immune activation is a hallmark of MS.
Treatments
- The most effective MS drugs reduce inflammatory and immune system responses.
Key Terms & Definitions
- Multiple Sclerosis (MS) — a disorder of the central nervous system involving myelin sheath damage.
- Myelin — the protective sheath covering axons, enabling efficient nerve signal conduction.
- Axon — the part of a neuron that carries electrical impulses.
- Plaque/Lesion — damaged regions in the brain visible on imaging, indicative of demyelination.
- Autoimmune Disease — condition where the immune system attacks the body’s own tissues.
- Glial Cells — supportive cells in the central nervous system.
Action Items / Next Steps
- Review neuroimaging showing MS lesions.
- Study the immune system’s role in other neurological diseases.