A severe and often fatal illness produced by exposure to excessively high temperatures, especially when accompanied by marked exertion.
It can manifest by elevated body temperature, lack of sweating, hot dry skin, and neurologic symptoms; unconsciousness, paralysis, headache, vertigo, confusion. In severe cases very high fever, vascular collapse, and coma develop.
Synonym: heat apoplexy, heat hyperpyrexia, malignant hyperpyrexia, thermic fever.
(05 Mar 2000)