Multiple sclerosis: an animated, cited guide
This page needs JavaScript for its animations. The outline and key answers are below, and every claim in the full version carries a numbered citation.
Not medical advice. MS Companion is an educational synthesis of published literature. It does not replace a clinician.
What is in it
- What MS is Who gets it, the numbers, and where in the nervous system it strikes.
- Myelin and demyelination How signals jump along a myelinated nerve fibre, and what a lesion does to them.
- The immune attack T cells, B cells and the blood-brain barrier, step by step.
- Genes and risk factors HLA-DRB1*15:01, Epstein-Barr virus, vitamin D, smoking and teenage obesity.
- Relapse and remission over time Relapsing, secondary progressive and primary progressive MS on one timeline.
- A relapse, week by week Onset, steroids and recovery, and how a pseudo-relapse differs.
- Measuring disability: EDSS The 0 to 10 scale and what confirmed worsening means.
- McDonald criteria calculator Dissemination in space and time, CSF, and the 2017 and 2024 rules.
- The differential NMOSD, MOGAD and other conditions that look like MS.
- How the drugs work Where each disease-modifying therapy acts.
- The DMT ladder Escalation, early high-efficacy treatment and stopping in later life.
- Safety and monitoring PML and the JCV index, infections, vaccines and rebound.
- Toward a cure Remyelination, BTK inhibitors, stem-cell transplantation and EBV.
- Symptoms and rehabilitation Fatigue, spasticity, bladder, walking, mood and cognition.
- Living with MS Pregnancy, work, heat, exercise and planning.
- Nursing care Assessment, giving the medicines, monitoring and teaching.
- History and people From Carswell and Charcot to the 2024 criteria.
- Flashcards, quiz and glossary Revision for students.
- Sources Every reference behind the app.
Common questions
What is multiple sclerosis?
Multiple sclerosis is a long-term immune-mediated disease of the brain, spinal cord and optic nerves. Immune cells damage myelin, the insulation around nerve fibres, and the fibres themselves, so nerve signals slow down or fail. Symptoms depend on where the damage is: vision, sensation, strength, balance, bladder and thinking can all be affected.
How common is multiple sclerosis?
The Atlas of MS counted about 2.8 million people with MS worldwide in 2020, or 35.9 per 100,000, and its 2024 update estimated 3.1 million. Mean age at diagnosis is about 32, and women are affected about twice as often as men.
What are the first symptoms of MS?
Most often a single episode of the optic nerve, brainstem or spinal cord, called a clinically isolated syndrome. In a large Barcelona cohort the first attack involved the optic nerve in 34.1% of people, the spinal cord in 29.5% and the brainstem in 25.1%.
How is MS diagnosed?
With the McDonald criteria, last revised in 2024. Doctors look for damage in more than one part of the central nervous system (dissemination in space) and, depending on the route, evidence from more than one time, from spinal fluid or from MRI signs such as the central vein sign, and they must rule out other explanations.
Is MS hereditary?
Not in a simple way. More than 200 common gene variants each nudge risk up a little; the strongest, HLA-DRB1*15:01, roughly quadruples it per copy. In a Swedish registry, the absolute risk was about 2.55% for a sibling and 2.03% for a child of someone with MS.
Does the Epstein-Barr virus cause MS?
Infection with Epstein-Barr virus appears to be nearly a precondition: among more than 10 million young adults in the US military, MS risk rose 32-fold after EBV infection and not after other viruses. But almost everyone carries EBV and very few develop MS, so it is not sufficient on its own.
What is the difference between relapsing and progressive MS?
In relapsing MS, attacks of new or worse symptoms come and then improve, partly or fully. In progressive MS, disability increases gradually, with or without relapses. In the Lyon cohort 15% had a progressive course from onset. Much of the disability in relapsing MS also builds up silently, without relapses.
Is pregnancy safe with MS?
In the PRIMS study the relapse rate fell from 0.7 a year before pregnancy to 0.2 in the third trimester, then rose to 1.2 in the first three months after birth before settling. Some disease-modifying drugs must be stopped well before conception, so labels and guidelines advise planning with the neurologist.