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MS Relapse vs Pseudo-Relapse – Differentiation — SCE Neurology MCQ

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EasyMultiple Sclerosis & CNS InflammationMS Relapse vs Pseudo-Relapse – DifferentiationSCE Neurology

A 55-year-old man with MS on a DMT develops new neurological symptoms that could represent either a genuine MS relapse or a pseudo-relapse from a concurrent infection. How should the clinician differentiate between the two?

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Correct answer: A — Screen for infection (urinalysis, CXR, blood cultures, FBC, CRP) and check temperature — pseudo-relapses are caused by infection, fever, or other stressors that temporarily worsen pre-existing MS symptoms (Uhthoff phenomenon), while true relapses represent new inflammatory demyelination and should show new lesions on MRI with gadolinium enhancement

Differentiating true MS relapses from pseudo-relapses is a common clinical challenge. Key approach: (1) Screen for infection/fever (UTI is the most common trigger for pseudo-relapse), (2) Assess whether the symptoms are NEW (true relapse) or worsening of EXISTING deficits (pseudo-relapse), (3) MRI with gadolinium — new enhancing lesions support a true relapse, (4) Treat any identified infection first — pseudo-relapse symptoms resolve when the infection is treated. True relapses require ≥24 hours of new symptoms without fever/infection. A: A systematic approach can usually differentiate. C: Clinical assessment is also important. D: LP is not usually needed. E: Clinical assessment is the clinician's role.

Reference: NICE NG100 MS; ABN MS Guidelines