Neurology · PANCE / PANRE

Multiple Sclerosis

Written & clinically reviewed by Ryan Busch, PA-C · Updated August 2026 · Report an error

Autoimmune CNS demyelinating disease with relapsing or progressive course.

Also known as: MS, multiple sclerosis, RRMS, SPMS, PPMS

Overview

Chronic autoimmune inflammatory demyelinating disease of the central nervous system, characterized by lesions disseminated in space (multiple CNS locations) and time (multiple episodes or accumulation over time). Phenotypes: relapsing-remitting (RRMS, ~85%), secondary progressive (SPMS, evolves from RRMS), primary progressive (PPMS, ~10-15%), and clinically isolated syndrome (CIS, first demyelinating event).

Epidemiology

Prevalence ~1 million in the US. Typical onset age 20-40. Female-to-male ratio ~3:1. Higher prevalence at higher latitudes (vitamin D, EBV link).

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Question 1NeurologyMedium
A 42-year-old female has had 2 attacks over 2 years: unilateral optic neuritis and transverse myelitis. MRI brain shows periventricular white matter lesions in a Dawson fingers pattern. CSF has oligoclonal bands. Anti-aquaporin-4 (anti-AQP4) antibody is negative. Which of the following is the most appropriate next step in management?
  • ASupportive care only
  • BObservation
  • CEculizumab
  • DOcrelizumab
Reveal answer & full explanation
Correct answer: D — Ocrelizumab
  • ASupportive care only
  • BObservation
  • CEculizumab
  • DOcrelizumab✓

Why Ocrelizumab is correct

  • This patient meets McDonald criteria (2017) for relapsing-remitting multiple sclerosis (RRMS): dissemination in space (periventricular, juxtacortical, infratentorial, or spinal cord lesions) plus dissemination in time (2 attacks over 2 years)
  • Dawson fingers are periventricular lesions perpendicular to the ventricles on sagittal MRI — present here
  • Negative anti-aquaporin-4 (anti-AQP4) makes neuromyelitis optica spectrum disorder (NMOSD) unlikely
  • TREAT-MS and DELIVER-MS trials support early high-efficacy therapy for young patients with active disease
  • Ocrelizumab (anti-CD20) is superior to interferon-beta-1a (IFN-beta-1a) (OPERA I/II trials) and is also FDA-approved for primary progressive multiple sclerosis (MS) (ORATORIO trial)

Why the others are wrong

  • Supportive care only — active RRMS with two attacks requires disease-modifying therapy; supportive care alone is inadequate (undertreatment)
  • Observation — two attacks with MRI and CSF evidence of MS warrant treatment, not watchful waiting (premature closure)
  • Eculizumab — used in NMOSD, not RRMS; this patient is anti-AQP4 negative, making NMOSD unlikely (confused-with NMOSD)

Additional high-yield points

  • CRITICAL: First exclude NMOSD before starting MS drugs — interferons, natalizumab, and fingolimod can WORSEN NMOSD
Question 2NeurologyMedium
A 32-year-old woman presents with a 2-day history of right eye pain worsening with eye movement, followed by blurry central vision in the right eye. Visual acuity is 20/200 on the right. Fundoscopy is normal. MRI brain shows 3 periventricular T2 hyperintense lesions. Oligoclonal bands are present in cerebrospinal fluid (CSF). Which of the following is the most appropriate acute treatment?
  • AObservation only
  • BIntramuscular interferon beta-1a
  • CIntravenous methylprednisolone
  • DOral high-dose prednisone
Reveal answer & full explanation
Correct answer: C — Intravenous methylprednisolone
  • AObservation only
  • BIntramuscular interferon beta-1a
  • CIntravenous methylprednisolone✓
  • DOral high-dose prednisone

Why Intravenous methylprednisolone is correct

  • This presentation is optic neuritis — right eye pain worsening with eye movement, blurry central vision, and visual acuity 20/200 — the first demyelinating event likely representing multiple sclerosis (MS)
  • Periventricular lesions and oligoclonal bands in cerebrospinal fluid (CSF) fulfill McDonald criteria for MS diagnosis
  • Acute treatment is IV methylprednisolone 1 g/day × 3–5 days, which speeds visual recovery (though it does not improve final visual acuity)

Why the others are wrong

  • Oral high-dose prednisone — oral prednisone for optic neuritis is associated with an increased relapse rate and is contraindicated
  • Intramuscular interferon beta-1a — disease-modifying therapy (interferon beta, glatiramer, etc.) is started after acute treatment for relapsing-remitting MS, not as the acute intervention
  • Oral observation only — observation is inappropriate with significant visual loss
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Risk factors

  • Female sex
  • Age 20-40
  • Higher latitude of residence (especially before age 15)
  • Vitamin D deficiency
  • Epstein-Barr virus infection (EBV — strong epidemiologic association; recent prospective evidence supports causal role)
  • Smoking
  • Obesity in adolescence
  • Family history (HLA-DRB1*15:01 strongest genetic association)
  • Northern European ancestry

Pathophysiology

Autoreactive T cells (and B cells) cross a disrupted blood-brain barrier, attack myelin and oligodendrocytes, and produce demyelinating plaques in white matter (and increasingly recognized cortical lesions). Acute inflammation causes relapses; chronic neurodegeneration with axonal loss drives progressive disability. B cell roles (antibody, antigen presentation) explain efficacy of anti-CD20 therapies.

Clinical presentation

Symptoms

  • Optic neuritis: subacute monocular vision loss with pain on eye movement, dyschromatopsia (red desaturation), afferent pupillary defect
  • Internuclear ophthalmoplegia (INO): impaired adduction of the ipsilateral eye on horizontal gaze with nystagmus of the abducting eye — bilateral INO in a young patient is highly suggestive of MS
  • Sensory: paresthesias, numbness, Lhermitte sign (electric shock down spine with neck flexion)
  • Motor: weakness, spasticity, hyperreflexia
  • Cerebellar: ataxia, intention tremor, dysarthria
  • Bowel/bladder dysfunction (urgency, incontinence, retention)
  • Fatigue (most common and disabling symptom)
  • Uhthoff phenomenon: symptom worsening with heat (exercise, hot shower, fever)
  • Cognitive impairment, depression

Signs / physical exam

  • Optic disc pallor (chronic optic neuritis), RAPD
  • INO, abnormal smooth pursuit, gaze-evoked nystagmus
  • Spastic paraparesis, hyperreflexia, Babinski sign
  • Sensory level (in transverse myelitis), impaired vibration/proprioception
  • Cerebellar findings: dysmetria, dysdiadochokinesia

Classic findings

Young woman with optic neuritis + INO + multiple episodes of neurologic symptoms over time.

Differential diagnosis

  • Neuromyelitis optica spectrum disorder (NMOSD) — Longitudinally extensive transverse myelitis (≥3 vertebral segments), severe optic neuritis often bilateral, AQP4-IgG antibody positive
  • MOG antibody-associated disease (MOGAD) — Optic neuritis, transverse myelitis, ADEM-like in children; MOG-IgG positive
  • Acute disseminated encephalomyelitis (ADEM) — Monophasic, post-infectious or post-vaccination, encephalopathy prominent, multifocal lesions, often pediatric
  • Lyme disease, neurosyphilis, HIV — Serology, CSF studies; geographic and risk-factor clues
  • Vitamin B12 deficiency (subacute combined degeneration) — Posterior column dysfunction, megaloblastic anemia, low B12
  • Vasculitis (CNS or systemic) — Constitutional symptoms, multi-system involvement, ESR/CRP, ANCA, biopsy
  • Sarcoidosis — Pulmonary findings, ACE level, basal meningeal enhancement on MRI
  • Migraine with white matter lesions — Headache history, lesions typically subcortical and asymptomatic; clinical correlation

Diagnostic workup

Diagnostic criteria

2017 McDonald criteria: dissemination in space (≥1 T2 lesion in ≥2 of 4 CNS regions: periventricular, cortical/juxtacortical, infratentorial, spinal cord) AND dissemination in time (simultaneous gadolinium-enhancing and non-enhancing lesions OR new lesion on follow-up MRI OR oligoclonal bands in CSF unique from serum).

Labs

  • CBC, BMP, LFTs, TSH, B12, RPR, HIV, vitamin D, ANA
  • Aquaporin-4 (AQP4) IgG — rules out NMOSD
  • MOG IgG — rules out MOGAD
  • Lyme serology if regional exposure

Imaging

  • MRI brain with and without gadolinium — periventricular, juxtacortical, infratentorial, and spinal cord lesions; ovoid lesions perpendicular to ventricles (Dawson fingers); enhancement indicates active inflammation (~6 weeks)
  • MRI cervical and thoracic spine — short-segment cord lesions (<2 vertebral segments — contrasts with NMOSD)
  • Optical coherence tomography (OCT) — retinal nerve fiber layer thinning
  • Visual evoked potentials — delayed P100 (subclinical optic nerve involvement)

Diagnostic algorithm

SubtypeCourseFrequency
Clinically isolated syndrome (CIS)First demyelinating event; may convert to MS~initial presentation
Relapsing-remitting (RRMS)Acute relapses with recovery; stable between~85% at onset
Secondary progressive (SPMS)Gradual worsening after initial RRMS phaseEvolves from RRMS over 10-20 years
Primary progressive (PPMS)Gradual worsening from onset, no clear relapses~10-15%
Radiologically isolated syndrome (RIS)MRI findings without symptomsPre-clinical; some convert to MS
Multiple sclerosis clinical phenotypes (2013 Lublin revision).

Treatment

First-line

  • Acute relapse: IV methylprednisolone 1 g/day × 3-5 days (speeds recovery; does not change long-term disability)
  • Plasma exchange (PLEX) for severe relapses unresponsive to steroids
  • Disease-modifying therapy (DMT) — start early for RRMS
  • Moderate efficacy DMTs: interferon beta (Avonex, Rebif, Betaseron, Plegridy), glatiramer acetate (Copaxone), teriflunomide, dimethyl fumarate, diroximel fumarate
  • High efficacy DMTs (often first-line now): anti-CD20 monoclonal antibodies — ocrelizumab (also FDA-approved for PPMS), ofatumumab, rituximab (off-label); fingolimod (S1P modulator); natalizumab (anti-VLA4 — caution PML risk with JCV+); cladribine; alemtuzumab

Second-line / adjunct

  • Symptomatic management: spasticity (baclofen, tizanidine, gabapentin, botulinum toxin), neuropathic pain (gabapentin, pregabalin, duloxetine), fatigue (amantadine, modafinil, lifestyle), bladder (oxybutynin, mirabegron, intermittent catheterization), depression (SSRIs), gait (dalfampridine)
  • Vitamin D supplementation (>1000 IU/day target serum 25-OH-D >30 ng/mL)
  • Vaccinations BEFORE starting immunosuppressive DMT (avoid live vaccines during therapy)
  • Smoking cessation
  • Physical therapy, occupational therapy, multidisciplinary MS care

Complications

  • Progressive disability accumulation (EDSS scale)
  • Cognitive impairment (~40-70% of patients)
  • Depression (high rates, increased suicide risk)
  • Bladder dysfunction with recurrent UTIs
  • Mobility loss, falls
  • PML (progressive multifocal leukoencephalopathy) — opportunistic JC virus infection in natalizumab- or other immunosuppressant-treated patients
  • Increased infection risk with anti-CD20 and other immunosuppressive DMTs
  • Pseudo-relapse: symptom worsening from infection, heat, or stress without new inflammation

PANCE pearls

  • MS lesions are 'separated in time and space' — the diagnostic hallmark.
  • Bilateral INO in a young patient is MS until proven otherwise.
  • Long-segment (≥3 vertebrae) transverse myelitis suggests NMOSD, NOT MS — check AQP4-IgG.
  • Oligoclonal bands in CSF (unique from serum) support MS diagnosis and predict conversion from CIS.
  • Start DMT early — disability accrual is fastest in the first decade; high-efficacy first-line therapy is favored in many recent algorithms.
  • EBV is now considered a causal factor in MS (Bjornevik et al., Science 2022).

References

  • AAN 2018 — Practice Guideline Recommendations Summary: Disease-Modifying Therapies for Adults With MS (Rae-Grant et al., Neurology 2018)
  • McDonald 2017 — Diagnosis of MS: 2017 Revisions of the McDonald Criteria (Thompson et al., Lancet Neurol 2018)
  • ECTRIMS 2018 — ECTRIMS/EAN Guideline on Pharmacological Treatment of People with MS (Montalban et al., Mult Scler 2018)
  • EBV-MS — Longitudinal Analysis Reveals High Prevalence of EBV Associated with MS (Bjornevik et al., Science 2022)

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Differentials & related conditions

Sarcoidosis

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