Pseudorelapse in Multiple Sclerosis
A pseudorelapse (also called a pseudoattack) is the temporary worsening or recurrence of previous MS neurological symptoms triggered by external factors such as elevated core body temperature, infection, or metabolic disturbances—rather than new inflammatory demyelinating activity. 1
Key Distinguishing Features
Pseudorelapses differ from true MS relapses in their underlying mechanism:
True relapses represent new episodes of neurological disturbance caused by inflammatory and demyelinating lesions in the central nervous system, lasting at least 24 hours with objective clinical findings 1
Pseudorelapses represent symptom fluctuation without new inflammatory activity, triggered by reversible physiological stressors 2
Common Triggers
The most frequently identified precipitants of pseudorelapse include:
- Elevated core body temperature (fever, hot weather, hot baths, exercise) 1
- Active infections (particularly urinary tract infections) 3
- Metabolic derangements 3
- Fever from any cause 1
Clinical Recognition
Expert clinical assessment is essential to distinguish pseudorelapses from true relapses before initiating treatment: 1
- Pseudorelapses typically resolve once the triggering factor is addressed (e.g., treating infection, cooling body temperature) 2
- True relapses persist beyond 24 hours even after addressing potential triggers 1
- Objective neurological examination findings are required for diagnosing a true relapse 1
- MRI may help confirm true relapse by demonstrating new or enhancing lesions, though this is not always necessary 3
Clinical Implications
Recognizing pseudorelapses is critical to avoid unnecessary corticosteroid treatment and its associated risks: 4, 2
- Pseudorelapses should not be treated with high-dose corticosteroids 2
- Management focuses on identifying and treating the underlying trigger 3
- The expanding availability of oral corticosteroids makes accurate distinction even more important to prevent overtreatment 4
Patients should be evaluated for potential triggers (infection, fever, metabolic issues) before diagnosing a true MS relapse requiring immunosuppressive therapy. 3