Heat stroke in adults

Heat stroke is a medical emergency. Clinical features include a core body temperature >40°C and central nervous system dysfunction (e.g., altered level of consciousness ranging from confusion to coma [encephalopathy], seizures) in the context of passive exposure to severe environmental heat (classic heat stroke) or strenuous exercise (exertional heat stroke).

Use a rectal thermometer to measure core body temperature and monitor continuously. In practice, consider using an oesophageal probe in intubated patients.

Start rapid active cooling immediately, based on clinical suspicion regardless of degree of hyperthermia and measuring technique. Aim to achieve a target temperature of no less than 39°C. Stop cooling once this temperature is reached.

Cold or ice water immersion is the preferred method for patients with exertional heat stroke. Use wetting and fanning the skin in patients with classic heat stroke and consider wetted ice packs or chemical cold packs as adjunctive cooling.

Patients are at risk of multi-system organ failure, so careful monitoring is essential even after return to normothermia.

This topic covers the management of both heat stroke and heat exhaustion in adults

Heat stroke is defined as a core temperature >40°C with central nervous system dysfunction (e.g., altered level of consciousness ranging from confusion to coma [encephalopathy], seizures).[1]Lipman GS, Gaudio FG, Eifling KP, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of heat illness: 2019 update. Wilderness Environ Med. 2019 Dec;30(4s):S33-46. https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext http://www.ncbi.nlm.nih.gov/pubmed/31221601?tool=bestpractice.com  Heat stroke is generally divided into classic heat stroke (due to passive exposure to severe environmental heat) and exertional heat stroke (due to strenuous physical exercise).[1]Lipman GS, Gaudio FG, Eifling KP, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of heat illness: 2019 update. Wilderness Environ Med. 2019 Dec;30(4s):S33-46. https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext http://www.ncbi.nlm.nih.gov/pubmed/31221601?tool=bestpractice.com  

Heat exhaustion is a mild to moderate heat illness.[1]Lipman GS, Gaudio FG, Eifling KP, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of heat illness: 2019 update. Wilderness Environ Med. 2019 Dec;30(4s):S33-46. https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext http://www.ncbi.nlm.nih.gov/pubmed/31221601?tool=bestpractice.com  The patient presents with a normal or slightly elevated core temperature (37°C to 40°C), mild neurological symptoms (e.g., intense thirst, weakness, anxiety, dizziness, syncope), and an intact mental status.[1]Lipman GS, Gaudio FG, Eifling KP, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of heat illness: 2019 update. Wilderness Environ Med. 2019 Dec;30(4s):S33-46. https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext http://www.ncbi.nlm.nih.gov/pubmed/31221601?tool=bestpractice.com [2]Gauer R, Meyers BK. Heat-related illnesses. Am Fam Physician. 2019 Apr 15;99(8):482-9. https://www.aafp.org/afp/2019/0415/p482.html http://www.ncbi.nlm.nih.gov/pubmed/30990296?tool=bestpractice.com  If untreated, heat exhaustion can progress to heat stroke. Heat stroke, however, can occur without preceding heat exhaustion.[1]Lipman GS, Gaudio FG, Eifling KP, et al. Wilderness Medical Society clinical practice guidelines for the prevention and treatment of heat illness: 2019 update. Wilderness Environ Med. 2019 Dec;30(4s):S33-46. https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext http://www.ncbi.nlm.nih.gov/pubmed/31221601?tool=bestpractice.com