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. Electrocardiographic abnormalities include conduction disturbances and ST-T segment changes. In practical terms, the major challenge is to distinguish classic heatstroke from sepsis and to distinguish exertional heatstroke from less severe exercise-induced abnormalities, such as exertional hyperthermia and heat exhaustion. The patient should be protected from sunlight and should be moved to a cool environment and evacuated to an emergency ward as soon as possible.