ICU · Toxicology

Heat stroke and hyperthermia in the ICU

Also known as Heat stroke · Exertional heat stroke · Non-exertional heat stroke · Classic heat stroke · Heat-related illness · Malignant hyperthermia (differential)

Heat stroke is a life-threatening condition defined by core temperature 40C with CNS dysfunction (confusion, seizures, coma). Two types: EXERTIONAL (young, healthy, exercise in heat — e.g., athlete, military) and NON-EXERTIONAL/CLASSIC (elderly, chronic disease, during heatwaves). Pathophysiology: thermoregulatory failure → direct thermal cellular damage (protein denaturation, membrane injury) + systemic inflammatory response (cytokine cascade resembling sepsis) → multi-organ failure (brain, heart, liver, kidney, muscle, coagulation/DIC). Management: RAPID COOLING (target <39C within 30-60 min) — cold water immersion gold standard for exertional, evaporative (mist + fans) for non-exertional, stop aggressive cooling at 38.5-39C. Antipyretics INEFFECTIVE (not prostaglandin-mediated). Dantrolene INEFFECTIVE (not malignant hyperthermia). Mortality 10-50%.