Catecholamines in heat stroke.

In order to find out whether the sympatho-adrenal system is activated in relation to heat stroke, plasma levels of norepinephrine (NE) and epinephrine (E) were measured using high pressure liquid chromatography in seven patients with heat stroke. The mean NE +/- SD levels on admission and six hours afterwards were 1397 +/- 317 and 717 +/- 239 pg/ml, respectively. The corresponding values for E were 257 +/- 55 and 32 +/- 15 pg/ml. The levels of both NE and E on admission were considerably higher than those of the controls: 328 +/- 62 and 88 +/- 16 pg/ml (12 normal subjects). This increase in both NE and E indicates activation of the sympatho-adrenal system in patients with heat stroke. The alpha-mediated effect of catecholamines may be important in impairing heat dissipation and thus may contribute to the pathogenesis of heat stroke.