Uhthoff's phenomenon in multiple sclerosis. Defined as a transient worsening of MS symptoms when body temperature increases. It affects 50-80% of MS patients. Typically episodes last 30 minutes when patient begins to cool down. The phenomenon is due to temperature-induced decreases in axonal conduction.
Patient refused ER transport. She rested in the shade and with cold drinks. After 30 minutes she felt completely better. All neurologic abnormalities on exam resolved.
Against medical advice she returned to finish the race.
Previously MS patients were discouraged from exercise due to Uhthoff's phenomenon and concern about fatigue. Recently that view has changed due to the fitness and psychological benefits gained by all people from exercise training. Exercise prescription per 2008 multiple sclerosis guidelines recommends endurance draining at low to moderate intensity. Exercise recommended in a cool environment with frequent breaks. Aquatic exercise is ideal with a life guard on duty. There are new devices available to cool core body temperature during exercise.
Interesting case! I would have liked additional follow up but recognize the limitations. I wonder if compartment syndrome of the thigh could also be included in the differential
Dalgas U, Stenager E, Ingemann-Hansen T. Multiple sclerosis and physical exercise: recommendations for the application of resistance, endurance, and combined training. Mult Scler. 2008 Jan; 14(1):35-53
White LJ, Dressendorfer RH. Exercise and multiple sclerosis. Sports Med. 2004; 34(15):1077-100
Meyer-Heim A, Rothmaier M, Weder M et al. Advanced lightweight cooling-garment technology: functional improvements in thermosensitive patients with multiple sclerosis. Mult Scler. 2007 Mar;13(2):232-7
Grahn DA, Murray JV, Heller HC. Cooling via one hand improves physical performance in heat-sensitive individuals with multiple sclerosis: a preliminary study. BMC Neurol. 2008 May 12;8:14
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