Despite differences in pathophysiology and epidemiology, the major manifestations of the classic and exertional heatstroke syndromes are similar. Disordered mentation is no less common and may span a spectrum ranging from confusion and lethargy to delirium, stupor, coma, and seizures. Despite the dramatic central nervous system manifestation of extreme hyperthermia, most patients who survive do not exhibit neurologic impairment. Virtually all patients with heatstroke also exhibit cardiovascular abnormalities. Leukocytosis is common, and hemoconcentration may raise the hematocrit in patients who are volume depleted.
Renal abnormalities are common in heatstroke.
Elevated bilirubin levels in patients with heatstroke may reflect hepatic injury, hemolysis, or both. Elevated transaminase levels are the rule, reflecting damage to both liver and muscle cells. Heatstroke causes multiple metabolic abnormalities. Potassium levels are variable, sometimes being low early and high later in the course of heatstroke. Hypoglycemia, perhaps reflecting depletion of glycogen stores, has been reported in many patients with exertional heatstroke.