Q: 32 year old female with a previous history of multiple sclerosis (MS) is admitted to ICU with a flare of her symptoms. Neurology service diagnosed her with the Uhthoff phenomenon. What is Uhthoff phenomenon?
Answer: Transient flare-up of symptoms of MS due to increase in body temperature
Uhthoff phenomenon, named after a german ophthalmologist Wilhelm Uhthoff, is a transient (less than 24 hours) worsening of neurological function among MS patients in response to increases in core body temperature. This is distinct from the true relapse or exacerbation of MS. It does not require corticosteroid pulse therapy or plasma exchange therapy. It has been described in other neuropathies too. The mechanism of action is the temperature-sensitive conduction blockade of partially demyelinated axons in the demyelinated plaques. Precipitating factors include perimenstrual period, exercise, fever, hot bath, psychological stress, a hot meal, and smoking.
Treatment is rest and cooler environment.
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