Multiple Sclerosis
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Direct answer
Multiple sclerosis is an immune-mediated demyelinating disease of the central nervous system, usually relapsing-remitting at onset and diagnosed by demonstrating dissemination in space and time clinically or on MRI with the 2017 McDonald criteria. An acute relapse is treated with high-dose methylprednisolone, with plasma exchange reserved for severe steroid-refractory attacks. Long-term therapy escalates from platform injectables and orals to high-efficacy monoclonal antibodies, chosen by disease activity and risk — after neuromyelitis optica and MOG antibody disease have been excluded.
What you must remember
- 2017 McDonald dissemination in space: at least one T2 lesion in two or more of five areas — periventricular (three or more lesions), cortical or juxtacortical, infratentorial, spinal cord and optic nerve; symptomatic lesions count.
- 2017 refinements: dissemination in time can be shown by simultaneous enhancing and non-enhancing lesions at any single time point, and CSF-specific oligoclonal bands may substitute for dissemination in time in a clinically isolated syndrome.
- Courses: clinically isolated syndrome, relapsing-remitting (commonest), secondary progressive with or without activity, and primary progressive; a radiologically isolated syndrome is followed rather than automatically treated.
- Before committing to therapy, test AQP4-IgG and consider MOG-IgG, because neuromyelitis optica spectrum disorder worsens on several multiple sclerosis drugs.
- Relapse management: exclude infection first (fever or urinary infection produces pseudo-relapse), then methylprednisolone 1 g intravenously daily for three to five days; plasma exchange for severe steroid-refractory attacks.
- Therapy tiers: platform injectables (interferon beta, glatiramer); orals (dimethyl fumarate, teriflunomide, fingolimod, and siponimod for active secondary progressive disease); high-efficacy monoclonals (natalizumab with JC virus serology-guided progressive multifocal leukoencephalopathy risk, ocrelizumab for relapsing and early primary progressive disease, ofatumumab, alemtuzumab); Indian access and cost often shape the realistic ladder.
- Monitoring and symptomatic care: JC virus antibody status for natalizumab, lymphocyte counts for dimethyl fumarate; baclofen or tizanidine for spasticity, anticholinergics for detrusor overactivity with residual monitoring, and depression and fatigue treatment; interferon beta and glatiramer are the pregnancy-compatible options.
Common confusion
The traps cluster around mimics and definitions. A longitudinally extensive cord lesion, severe bilateral optic neuritis or intractable hiccups point away from multiple sclerosis toward NMOSD, while ADEM-like episodes with good recovery suggest MOG antibody disease. A pseudo-relapse during urinary infection is treated with antibiotics, not steroids. Onset after forty with progressive myelopathy demands exclusion of compressive and metabolic disease before a progressive label is applied. Finally, radiological activity on interval MRI, not symptoms alone, now drives escalation decisions.
Exam-focused takeaway
Carry five items into the hall: the five dissemination-in-space areas, oligoclonal bands substituting for dissemination in time, methylprednisolone 1 g for three to five days for true relapses, natalizumab's JC virus dependency, and ocrelizumab's role in primary progressive disease. Questions pair an MRI description with the criterion invoked or the escalation step, and the Indian version often asks which test prevents a catastrophic misdiagnosis — AQP4-IgG.
Frequently asked questions
What are the 2017 McDonald criteria for dissemination in space?
At least one T2 lesion in two or more of five areas: periventricular (three or more), cortical or juxtacortical, infratentorial, spinal cord and optic nerve.
How is an acute relapse treated?
Exclude infection first, then methylprednisolone 1 g intravenously daily for three to five days; plasma exchange is reserved for severe steroid-refractory attacks.
Which therapy suits primary progressive multiple sclerosis?
Ocrelizumab has trial support in early progressive disease with inflammatory activity; most other agents target relapsing forms.
What is the progressive multifocal leukoencephalopathy risk with natalizumab?
It relates to JC virus antibody status, treatment duration and prior immunosuppression, so serology-guided risk stratification is mandatory.
Can women with multiple sclerosis become pregnant?
Yes, with planning: interferon beta and glatiramer are considered compatible, relapses are treated conservatively, and postpartum rebound risk is monitored.