Exertional heat stroke in the collapsed soldier

(a) Recognition and cooling (8 marks). This is exertional heatstroke: a core temperature above 40 °C with central nervous system dysfunction during strenuous exercise; no specific therapy other than rapid cooling is available.^[14] Cool immediately by cold-water or ice-water immersion, the method proven to have the fastest cooling rates; in 274 race patients it cooled at 0.22 °C per minute with 100 per cent survival.^[17][16] Aim to reduce core temperature below 39 °C within 30 minutes.^[13]

(b) Justification and drugs (5 marks). Water immersion in cold, colder or ice water cooled faster than passive cooling, with no single water temperature range faster than another.^[5] Antipyretics, dantrolene and NSAIDs are not recommended for a heat casualty; in a randomised trial, dantrolene 2 mg/kg intravenously did not shorten cooling time.^[13][7] The circulatory failure is mostly distributive with relative or absolute hypovolaemia.^[9]

(c) Complications and prognosis (3 marks). Exertional heatstroke pathophysiology includes systemic inflammatory response syndrome and coagulopathy with disseminated intravascular coagulation, and in catastrophic cases with severe liver damage endotoxin leaks into the circulation.^[18] Patients generally require hospitalisation to monitor for complications despite rapid cooling, and those adequately cooled within 30 minutes have excellent outcomes.^[15]