<P> Some of the gastrointestinal symptoms of acute exertional heat stroke, such as vomiting, diarrhea, and gastrointestinal bleeding, may be caused by barrier dysfunction and subsequent endotoxemia . Ultraendurance athletes have been found to have significantly increased plasma endotoxin levels . Endotoxin stimulates many inflammatory cytokines, which in turn may cause multiorgan dysfunction . Experimentally, monkeys treated with oral antibiotics prior to induction of heat stroke do not become endotoxemic . </P> <P> There is scientific support for the concept of a temperature set point - that is, maintenance of an optimal temperature for the metabolic processes that life depends on . Nervous activity in the preoptic - anterior hypothalamus of the brain triggers heat losing (sweating, etc .) or heat generating (shivering and muscle contraction, etc .) activities through stimulation of the autonomic nervous system . The pre-optic anterior hypothalamus has been shown to contain warm sensitive, cool sensitive, and temperature insensitive neurons, to determine the body's temperature setpoint . As the temperature that these neurons are exposed to rises above 37 ° C, the rate of electrical discharge of the warm - sensitive neurons increases progressively . Cold - sensitive neurons increase their rate of electrical discharge progressively below 37 ° C . </P> <P> Hyperthermia is generally diagnosed by the combination of unexpectedly high body temperature and a history that supports hyperthermia instead of a fever . Most commonly this means that the elevated temperature has occurred in a hot, humid environment (heat stroke) or in someone taking a drug for which hyperthermia is a known side effect (drug - induced hyperthermia). The presence of signs and symptoms related to hyperthermia syndromes, such as extrapyramidal symptoms characteristic of neuroleptic malignant syndrome, and the absence of signs and symptoms more commonly related to infection - related fevers, are also considered in making the diagnosis . </P> <P> If fever - reducing drugs lower the body temperature, even if the temperature does not return entirely to normal, then hyperthermia is excluded . </P>

What happens when you have a fever of 108