Wednesday, June 28, 2023

Uhthoff phenomenon

Q: Uhthoff phenomenon occurs in? (select one)

A) cold
B) heat


Answer: B

Transient flare-up of symptoms of  Multiple Sclerosis (MS) due to an increase in body temperature

Uhthoff phenomenon, named after a German ophthalmologist Wilhelm Uhthoff, is a transient (usually 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 pulse 
corticosteroid or plasma exchange therapy. This is also called
 Uhthoff sign or Uhthoff syndrome. Precipitating factors include perimenstrual period, exercise, fever, hot baths, psychological stress, a hot meal, and smoking.

It has been described in all demyelinating disorders as well as other neuropathies. Nystagmus and other visual disorders are particularly prone to worsen in patients with MS after increased body temperature. Prophylactic 4-aminopyridine may help to reduce sensitivity to visual impairments. The mechanism of action is the temperature-sensitive conduction blockade of partially demyelinated axons in the demyelinated plaques.

Treatment is rest and a cooler environment.



#neurology 



References:


1. Opara JA, Brola W, Wylegala AA, Wylegala E. Uhthoff`s phenomenon 125 years later - what do we know today? J Med Life. 2016 Jan-Mar;9(1):101-105. 


2. Perkin GD, Rose FC. Uhthoff's syndrome. Br J Ophthalmol. 1976 Jan;60(1):60-3. 


3. Frohman TC, Davis SL, Beh S, Greenberg BM, Remington G, Frohman EM. Uhthoff's phenomena in MS--clinical features and pathophysiology. Nat Rev Neurol. 2013 Sep;9(9):535-40. 


4. van Diemen HA, van Dongen MM, Dammers JW, Polman CH. Increased visual impairment after exercise (Uhthoff's phenomenon) in multiple sclerosis: therapeutic possibilities. Eur. Neurol. 1992;32(4):231-4. 

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