When to suspect a multiple sclerosis (MS) flare?

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Last updated: May 2, 2025View editorial policy

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From the Guidelines

Suspect a multiple sclerosis (MS) flare when new or worsening neurological symptoms persist for more than 24 hours, in the absence of fever or infection, as this could indicate active inflammation in the central nervous system. Common signs of an MS flare include sudden vision problems, new or increased numbness or tingling, muscle weakness, balance problems, coordination difficulties, or increased fatigue that significantly impacts daily activities 1. Cognitive changes such as memory problems or difficulty concentrating may also indicate a flare. Bladder or bowel dysfunction that worsens suddenly should raise concern. These symptoms typically develop over hours to days and persist for days to weeks.

Key Symptoms to Look Out For

  • Sudden vision problems (blurred vision, double vision, or vision loss)
  • New or increased numbness or tingling
  • Muscle weakness
  • Balance problems
  • Coordination difficulties
  • Increased fatigue
  • Cognitive changes (memory problems or difficulty concentrating)
  • Bladder or bowel dysfunction If you experience these symptoms, contact your neurologist promptly as early treatment with corticosteroids may help reduce inflammation and shorten the duration of the flare. It's essential to distinguish true MS flares from pseudoflares, which are temporary worsening of symptoms due to heat exposure, stress, or infections without new inflammation or disease progression. During a true flare, MRI may show new or enhancing lesions in the brain or spinal cord, indicating active inflammation in the central nervous system, as discussed in the MAGNIMS consensus guidelines on the use of MRI in MS 1.

From the Research

Suspecting an MS Flare

To suspect an MS flare, it is essential to understand the characteristics of the disease and its treatment. Multiple sclerosis (MS) is an immune-mediated inflammatory disease of the central nervous system (CNS) that usually is clinically characterized by repeated subacute relapses followed by remissions 2.

Characteristics of an MS Flare

  • An MS flare is typically marked by new or worsening symptoms, such as vision problems, muscle weakness, or balance issues 2.
  • Relapses with moderate to serious disability should be treated with high dose intravenous or oral methylprednisolone 2.
  • MRI imaging can help detect active lesions and monitor the effectiveness of treatment 3, 4, 5.

Treatment and Its Effects

  • High dose short-term oral or intravenous methylprednisolone for 3-5 days can speed up recovery from relapses, but the treatment has no influence on the occurrence of new relapses or long-term disability 2.
  • The duration of the effect of methylprednisolone treatment is temporary, lasting on average 9.7 weeks 3.
  • Corticosteroids can reduce the duration and severity of clinical relapses in MS, while reducing the number of gadolinium-enhancing lesions on T1-weighted MRI 3, 5.

Monitoring Disease Activity

  • Quantitative measures of disease activity, such as brain parenchymal fraction (BPF) and magnetization transfer ratio (MTR), can be affected by corticosteroid treatment 6.
  • Changes in these measures can provide insight into the short-term effects of treatment and long-term implications for disease activity 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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