April 16, 2015: Uhthoff's phenomenon

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April 16, 2015

Uhthoff's phenomenon

In 1890, Wilhelm Uhthoff described ‘a temporary deterioration of visual acuity after physical exercise’ in patients with multiple sclerosis (MS)1. This phenomenon was later named after him. MS patients often experience short-lived worsening of their neurological symptoms when their body temperature rises. When this stereotypical worsening of symptoms persists for longer than 24 hours, the term ‘pseudoexacerbation’ is often used. Cooling can improve Uhthoff’s phenomenon, fatigue, postural instability, and weakness2. It is crucial to distinguish pseudoexacerbations from true MS exacerbations since management can differ greatly.


  1. Uhthoff W. Untersuchungen über die bei der multiplen Herdsklerose vorkommenden Augenstörungen. J Archiv für Psychiatrie und Nervenkrankheiten 1890; 21: 305-410.
  2. Beenakker EA, Oparina TI, Hartgring A, Teelken A, Arutjunyan AV, De Keyser J. Cooling garment treatment in MS: clinical improvement and decrease in leukocyte NO production. Neurology 2001; 57: 892-894.

Submitted by Raphael Schneider, MD Department of Neurology, University of Toronto, Canada.

Disclosures: Dr. Raphael Schneider is a member of the Residents & Fellows Section of Neurology.

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