A Hot Topic: Identification and Acute Management of Heat-Related Illness

Column Author: Andrew Donaldson, MD | Pediatric Resident

Column Editor: Kathleen Berg, MD, FAAP | Hospitalist - Pediatrics; Associate Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Assistant Professor of Pediatrics, University of Kansas School of Medicine

Summer in the Midwest brings fireworks, barbecues and pool days. With all that summer fun, pediatricians see an increase in heat-related illnesses (HRIs), including heat stroke. Annually, over 4,000 visits to United States emergency departments occur for HRI, 63.1% in June, July and August.¹ Nearly half of those suffering HRI are pediatric patients.² Whether caring for an infant left in a car or an adolescent athlete, it is vital that pediatricians understand how to identify and treat HRI. This article describes types of HRI, provides an overview of appropriate treatment, and discusses strategies to keep kids safe in the heat. 

Heat syncope is the sudden loss of consciousness after the completion of physical activity. Vasodilation during exercise in the heat leads to venous pooling and orthostasis. Those afflicted will rapidly regain consciousness once on the ground. Body temperature is typically normal.² Patients may require evaluation for secondary injuries from their fall. Occurrence of syncope post-exercise rather than during exercise distinguishes heat syncope from more sinister cardiac disorders. However, if the history is unclear, one should consider additional cardiac evaluation.³ 

Heat exhaustion occurs when the body’s natural thermoregulatory strategies are overwhelmed, leading to an inability to continue exercise accompanied by fatigue, nausea, feeling faint, and malaise. It is important to distinguish this condition from heat stroke. In heat exhaustion, patients are usually very sweaty, whereas in heat stroke, they may be dry. Though fatigue is a component of heat exhaustion, these patients should not have altered mental status.^3,4 The treatment is discontinuation of exercise and reduction of heat exposure. Encouraging consumption of cool liquids is important to treat the dehydration that often accompanies this condition.⁵ 

Heat stroke is the most severe form of HRI. In the United States, an average of 37 children die annually from heat stroke after being left in vehicles.² On average, two high school football players die annually from heat stroke related to exercise.² Though symptoms of heat exhaustion and heat stroke overlap, victims of heat stroke will have a core body temperature (CBT) greater than 104 F combined with altered mental status. Additionally, they may have a shock-like appearance with hypotension, tachycardia and respiratory distress. When evaluating for heat stroke, a rectal temperature is the most accurate and reliable method for determining CBT.  

Once you diagnose heat stroke, address circulation, airway and breathing, and begin cooling measures immediately. Move the patient to a cool environment and remove clothing. Cold-water immersion is preferred for older children. While adolescent-specific evidence is lacking, a meta-analysis of 63 adult studies found that cold-water immersion provided faster decrease in CBT compared to passive cooling measures.⁶ If immersion is not possible on site, use evaporative strategies like spraying with water and applying cold, wet towels. Less evidence is available for infants and young children, for whom evaporative strategies may be preferred to avoid reflex bradycardia. Ideally, the CBT would be 102 F or less prior to transport to the hospital.⁷ 

Prevention of HRI is key. Anticipatory guidance about car safety, including locking the car when not in use, can save the lives of our youngest and most vulnerable patients. In a study of 541 children who died of heat stroke after being left in a vehicle, the mean age was 16.4 months. In 16.6% of these cases, the responsible individual knowingly left the child in the vehicle.⁸ KidsAndCars.org has a plethora of useful information to provide to families on this topic. Encouraging caregivers to place a significant item such as phone or wallet in the back seat with the child can remind parents to look in the back before getting out of the car.²  

The National Federation of State High School Associations provides guidelines on HRI prevention for athletes.⁹ Acclimatization is of quintessential importance, with gradual increases in practice intensity over one to two weeks. Scheduling practice during cooler times of day, limiting practice time in full pads and uniform, and ensuring the ready availability of water before, during and after practice are strategies to help prevent HRI.^2,9,10 Use of the heat index and wet bulb globe temperature helps identify risk for HRI.⁹ Finally, preparation is essential. We should provide education to families, athletes and coaches on the identification of HRI, recommended cooling strategies, and importance of a solid emergency action plan.² 

References: 

1. Wu X, Brady JE, Rosenberg H, Li G. Emergency department visits for heat stroke in the United States, 2009 and 2010. Inj Epidemiol. 2014;1(1):8. Epub 20140424. PMID: 27747667; PMCID: PMC5005673. doi:10.1186/2197-1714-1-8  
2. Mangus CW, Canares TL. Heat-related illness in children in an era of extreme temperatures. Pediatr Rev. 2019;40(3):97-107. doi:10.1542/pir.2017-0322 
3. Constance DG, Baker RJ. Chapter 38. Environment-related conditions. In: Patel DR, Greydanus DE, Baker RJ, eds. Pediatric Practice: Sports Medicine. The McGraw-Hill Companies; 2009. 
4. Ayeni AT, Kelly C. Heat and cold illness. In: Tenenbein M, Macias CG, Sharieff GQ, Yamamoto LG, Schafermeyer R, eds. Strange and Schafermeyer’s Pediatric Emergency Medicine. 5th ed. McGraw-Hill Education; 2019. 
5. Kenny GP, Wilson TE, Flouris AD, Fujii N. Heat exhaustion. Handb Clin Neurol. 2018;157:505-529. PMID: 30459023. doi:10.1016/b978-0-444-64074-1.00031-8  
6. Douma MJ, Aves T, Allan KS, et al. First aid cooling techniques for heat stroke and exertional hyperthermia: a systematic review and meta-analysis. Resuscitation. 2020;148:173-190. doi:10.1016/j.resuscitation.2020.01.007 
7. Armstrong LE, Casa DJ, Millard-Stafford M, Moran DS, Pyne SW, Roberts WO. Exertional heat illness during training and competition. Med Sci Sports Exerc. 2007;39(3):556-572. 
8. Hammett DL, Kennedy TM, Selbst SM, Rollins A, Fennell JE. Pediatric heatstroke fatalities caused by being left in motor vehicles. Pediatr Emerg Care. 2021;37(12):e1560-e1565. doi:10.1097/PEC.0000000000002115 
9. National Federation of State High School Associations Sports Medicine Advisory Committee. Heat acclimatization and heat illness prevention position statement. National Federation of State High School Associations; 2022. 
10. Bergeron MF, DiLaura Devore C, Rice SG; Council on Sports Medicine and Fitness and Council on School Health. Climatic heat stress and exercising children and adolescents. Pediatrics. 2011;128(3):e741-e747. doi:10.1542/peds.2011-1664