Progressive inflammatory disorder primarily manifesting with demyelination of the central white matter
Optic neuritis and transverse myelitis (spinal cord lesion) are common presentations
Generally develops over a few days; very uncommon to happen suddenly (e.g. pts will complain about a dark spot appearing in their vision that expands over several days)
Evaluation
MRI w/wo contrast can identify lesions and determine chronicity.
“Active” MS plaque will contrast enhance and continues to enhance for weeks (even after treatment).
2024 MacDonald Criteria: at least one characteristic demyelinating lesion (optic nerve, periventricular, infratentorial (brainstem/cerebellum/cord), juxtacortical/cortical in location) with evidence of separation in time (active and chronic). Positive oligoclonal bands or kappa free light chains on LP or central vein sign or parmagnetic rim lesions on imaging can substitute as dissemination in time.
Lumbar puncture with studies for oligoclonal bands, IgG index, cell count and protein, anti- MOG, anti-AQP4.
Management
Treat flares and optic neuritis with high-dose steroids.
Speeds up recovery, but does not improve the degree of recovery.
Often dosing starts with Methylprednisolone IV 1gm x 3-5 days.
If a pt with known MS has worsening of chronic symptoms, then recrudescence (pseudoflare) is the likely cause à infectious/toxic/metabolic workup is needed.
Steroid-sparing agents are the long-term therapy goal but often have significant adverse effects requiring monitoring:
Interferon (SQ injections): flu-like symptoms, injection site reactions.
Glatiramer acetate (SQ): injection site reactions.
