synonyms:heat stroke, heat exhaustion, dehydration, heat illness
Heat Illness ICD-10
Heat Illness ICD-9
- 992.0 Heat stroke and sunstroke Heat apoplexy Heat pyrexia ictus
Heat Illness Etiology / Epidemiology / Natural History
- Heat stroke: 10% mortality
- Heat cramps may be related to dehydration, diet poor in minerals, large sodium/electrolyte losses in sweat.
- Heat transfer to the environment occurs through conduction, convection, evaporation, and radiation.
- Evaporation of sweat is the primary mechanism regulating core temperature when the ambient temperature exceeds 35°C. (High humidity inhibits sweat evaporation)
Heat Illness Anatomy
Heat Illness Clinical Evaluation
- Heat cramps: muscle cramps, intense muscle pain.
- Heat Exhaustion: heat cramps with headache, weakness/fatigue, skin pale and moist, syncope, ataxia, incoordination, profuse sweating, no CNS changes.
- Heat stroked: Warm to the touch, no visible sweating, altered consciousness, coma, convulsions, disorientation, irrational behavior, irritability, confusion, combativeness. Tachycardia, hypotension, tachypnea. Confusion, delirium and bizzare behavior are often first signs
- Heat-related illness is defined as a core temperature above 40°C.
Heat Illness Xray / Diagnositc Tests
- Heat stoke = Rectal temperature >104°
- Heat Illness Risk Assessment: best done with Web bulb globe thermometer (WBGT); <65°F(18°C)=low risk; 65°-73°F (18°-23°C)=moderate risk; 73°-82°F (23°-28°C)=high; >82°F(28°C)=Extreme risk.
Heat Stroke Classification / Treatment
- Heat Cramps: move to cool dry place, rehydrate with carbohydrate/electrolyte containing sports drink.
- Heat Exhaustion: loosen clothing, apply ice to axilla and groin, drink cool water, cool water sprays, prop legs up.
- Heat Stroke: IV fluids and cooling. Immediate immersion in an ice water bath is the quickest and most efficent method of cooling. Consider also: cool water sprays, fans, ice bags in groin/axilla/neck. Transfer to ER ASAP.
Heat Illness Associated Injuries / Differential Diagnosis
- GI illness
Heat Stroke Complications
- Death: 10%
- End organ damage
- Hemodynamic collapse
Heat Illness Follow-up Care
- Prevention: maintain hydration, gradual acclimation to heat, avoid strenous exercise on high and extreme risk days.
- Heat stroke: no strenous exercise for at least 1 week with gradual return to activity after.
Heat Illness Review References
- Seto CK, Clin Sports Med 2005;21:695
- Smith JE, Br J Sports Med 2005;39:503
- Griffin LY, JBJS 2005;87:894
- Noonan B, Bancroft RW, Dines JS, Bedi A. Heat- and cold-induced injuries in athletes: evaluation and management. J Am Acad Orthop Surg. 2012 Dec;20(12):744-54.
- Howe AS, Boden BP. Heat-related illness in athletes. Am J Sports Med. 2007 Aug;35(8):1384-95.