Uhthoff’s Phenomenon—A Scare or Real Threat to Multiple Sclerosis Patients? A Narrative Review

Vollständiger Abstract

Worum geht es in dieser Arbeit?

Uhthoff’s phenomenon (UP) is a transient, fully reversible exacerbation of pre-existing neurological deficits in multiple sclerosis (MS) patients, triggered by minor elevations in core body temperature. In clinical practice, UP is a frequent source of distress, often misidentified as an acute inflammatory disease relapse. This narrative review provides a critical analysis of UP, addressing methodological heterogeneity in its epidemiological estimates, its clinical presentation, and its differential diagnosis from true relapses. Mechanistically, we synthesize traditional concepts of temperature-dependent conduction block with modern insights into neuroenergetic failure, mitochondrial dysfunction, inflammatory mediators, and autonomic dysregulation. Furthermore, this work delineates current management strategies, establishing a clear distinction between robust evidence-based interventions and expert-informed practical guidance for patient education, physical rehabilitation planning, targeted active/passive cooling, and pharmacological approaches. Characterized as a pseudo-relapse, UP occurs independently of novel focal neuroinflammation. In conclusion, an isolated episode of Uhthoff’s phenomenon (UP) represents a transient, functional conduction block and does not inflict acute, permanent structural damage to the axon. However, emerging frameworks suggest that frequent, repeated episodes subject the already demyelinated axon to recurrent metabolic strain. Over time, these successive neuroenergetic crises do not directly destroy the fiber, but they may gradually exhaust the cell’s metabolic reserve. This cumulative stress potentially increases long-term secondary axonal vulnerability, making the axon more susceptible to the progressive neurodegenerative processes inherent to multiple sclerosis.