OBJECTIVES: Fatigue is one of the most common and troubling symptoms of multiple sclerosis (MS), and heat is often reported as a trigger. Although it is assumed that this heat sensitivity is specific for MS, the evidence for disease specificity is limited. We studied the relationship between fatigue, heat sensitivity, and environmental temperature, and its specificity for MS.
MATERIALS AND METHODS: We compared 88 MS patients with 76 patients with ulcerative colitis (UC), another chronic auto-immune disease. As most important outcome measures, heat sensitivity, physical fatigue, mental fatigue, environmental temperature, and ambient UV-light levels were determined.
RESULTS: More patients with MS reported heat sensitivity for fatigue, compared to patients with UC (53.4% vs 35.5%, respectively, P = 0.016). However, heat-sensitive patients were equally fatigued as heat-insensitive patients. Climatological data, including day temperature and amount of ambient UV light, were not related to fatigue in both heat-sensitive and heat-insensitive patients with MS.
It seems that as spring is approaching we are seeing papers on heat being published, a few days ago we had cognition, yesterday the hot bath and today fatigue. It seems that fatigue is not as related as other MS symptoms. This may perhaps of something to do with pathogenesis; as conduction failure may be related to problems such as cognition. Fatigue is alleviated by effective inhibition of neuroinflammation so the inflammatory millieu may influence fatigue perhaps more than conduction effects.