Multiple Sclerosis Overview Quiz

Multiple Sclerosis (MS) Overview

• MS affects approximately 100,000 Canadians, with women being diagnosed more often than men (a ratio of more than three times).
• MS is the most common neurological disease in young adults (aged 15 to 40) in Canada.
• MS symptoms include loss of balance, impaired speech, severe fatigue, double vision, and paralysis.
• Possible causes of MS include bacterial or viral infection, pesticides, and the central nervous system's immune response.

MS Symptoms

• Abnormal sensations: "Pins and needles" sensation
• Bladder problems
• Difficulty walking: Muscle weakness or spasms
• Dizziness
• Fatigue: Weak muscles, slowed thinking, or sleepiness
• Muscle spasms: Mild stiffness to severe, painful spasms

MS Symptoms (detailed)

• Vision problems: Blurred vision, double vision, or paralysis of eye muscles
• Muscle stiffness: Lack of balance and coordination; loss of dexterity and fine movement
• Fatigue

Types of MS

• Relapsing-Remitting MS (RRMS): Short periods of worsening or relapses, followed by recovery periods. 85% of diagnosed MS are initially RRMS.
• Secondary-Progressive MS (SPMS): Slow, steady progression with or without relapses; most RRMS will transition to SPMS eventually
• Primary-Progressive MS (PPMS): Steady worsening from the start without periodic relapses or remissions; 10% of MS are PPMS.
• Progressive-Relapsing MS (PRMS): Steadily worsening from the start with episodic flare-ups with or without remissions. 5% of MS is PRMS.

Diagnosing MS

• A diagnosis requires evidence of disease activity in both time and space.
• MRI scans often reveal enlarging focal lesions (white spots) over time.
• Gadolinium enhancement in MRI scans identifies compromised blood-brain barriers or lesions with active inflammation.
• Spinal tap (lumbar puncture) is used for diagnosis; often shows an elevated level of oligoclonal banding and elevation of myelin basic proteins.
• Visual-evoked potentials (VEPs) detect conduction latency delays that are longer in those with MS (the time it takes for signals to reach the brain). However, conduction can be affected by unrelated conditions like tumors.

Causes of MS (Environmental factors)

• MS risk is higher in people living above 40° latitude in the Northern Hemisphere—correlated largely with Vitamin D deficiency.
• Movement from high-risk to low-risk areas during adolescence reduces MS risk, whereas moving from low-risk to high-risk areas increases it.
• A deficiency of vitamin D might play a substantial role.
• Infections with measles, human herpes virus-6, Epstein-Barr virus, and Chlamydia pneumoniae may increase the risk of MS. 90% of MS patients have also experienced Epstein-Barr virus infections like mononucleosis.

Causes of MS (Other Factors)

• Genomic and epigenetic, and regulatory events like gene rearrangements, messenger RNA splicing, retroviral sequences, methylation, and microRNAs affect the development of MS.
• Genome-wide allelic variants, consisting of single nucleotide polymorphisms, copy number variations, insertion/deletion polymorphisms, and disease-related genes, have been discovered to be associated with MS.

MS: Inflammatory Causes

• MS is considered an autoimmune disease, driven by the presence of T cells that recognize oligodendrocyte myelin-specific antigens.
• T cells cross the blood-brain barrier and release pro-inflammatory cytokines.
• In acute MS lesions, demyelination of axons, the activation of microglia, and the infiltration of immune (T) cells into the central nervous system (CNS) are prominent. The infiltrates mainly consist of T-cells and macrophages.
• An array of inflammatory agents is expressed within acute MS lesions.