Time for Heat-Related Illnesses and Injuries in Kids: Part 2 - Heat Stroke, Heat Exhaustion, and Dehydration

We are coming to the time of the year when heat-related illnesses and injuries are more common. In the US, July 4th is celebrated with fireworks and barbecues. Also, the summer sun is at its peak intensity. So, there is a higher risk for burns, heat stroke, heat exhaustion, and dehydration. Understanding these heat-related illnesses and injuries is essential to better prevent them from occurring, especially in the pediatric population. We previously discussed burns and, now, it is important to address heat stroke, heat exhaustion, and dehydration.

Heat-Related Illnesses

Heat stroke, heat exhaustion, and dehydration are a spectrum of conditions that are seen with exposure to environmental heat and inadequate fluid intake. Dehydration is a condition where one has a lower total body fluid amount than is normal and is seen with heat stroke and exhaustion. The severity of dehydration can range from no significant clinical symptoms that can be corrected by simple drinking of fluids to severe clinical symptoms, such as lower than normal blood pressure, requiring intravenous fluid infusions. The adult body composition is approximately 60% water and the infant body composition is approximately 75% water. So, hydration is a critical step to help prevent heat-related illness and dehydration with younger children and infants being most susceptible to loss of body water.

Heat exhaustion and heat stroke are characterized by a rising body temperature associated with other symptoms, in response to environmental heat exposure. Heat exhaustion is marked by a rising body temperature that does not exceed 40 degrees Celsius (104 degrees Fahrenheit) and is associated with excessive sweating with intact mental status. Heat stroke is the most severe, life-threatening form of heat-related illness and is defined by a rising body temperature of greater than 40 degrees Celsius with altered mental status and no sweating. Heat stroke occurs by exposure to severe heat with inadequate fluid intake and with or without intense activities. While body heat is normally dissipated by radiation of the body’s heat and evaporation of sweat, these protective mechanisms are nullified when the ambient temperature is greater than the body temperature and there is dehydration to prevent adequate sweating. Increased body heat, with the inability to dissipate heat, results in the inability of the body to regulate its own temperature. If this occurs, heat-related damage to the body occurs which can include brain, liver, kidney, and heart injuries, disruption of processes within the body, and even death.

Hyperpyrexia Is Not A Fever

It is important to differentiate the concept of hyperpyrexia from a fever, in the context of heat-related illnesses. Both are defined by an increase in the body’s temperature to some level above normal. However, with fever, the implication is that the temperature elevation is a physiologic response to something like an infection. So, the fever is an appropriate response to the circumstances affecting the body. Hyperpyrexia is also an increase in body temperature, but it is more extreme and it is not a physiologic response. Hyperpyrexia is the result of external forces increasing the body’s temperature to a level that is not physiologically appropriate or normal. Hyperpyrexia is the body’s loss of temperature regulation by something external, rather than a response to something internal. This difference in cause and response sets the stage for treatment protocols that include forcibly cooling the body during hyperpyrexia from environmental causes and not utilizing antipyretic medications, such as ibuprofen or acetaminophen. Antipyretic medications adjust the body’s physiologic response and lower the body temperature, but are completely ineffective and play no role in the treatment of heat-related illnesses caused by environmental heat.

Heat-Related Illness Prevention

Treatment of severe heat-related illness can be quite complicated and intensive with a focus on quickly lowering the body temperature and supporting the organs and biological processes that have been injured by the elevated body heat. So, the best treatment for heat-related illness is always prevention. Avoidance of excessive heat and providing hydration are the keys to successful prevention. In excessive heat environments, never leave young children unattended in a locked car, maintain good ventilation and use air conditioning when indoors, pre-hydrate and maintain fluid intake during exercise, and wear light-colored and loose-fitting clothes. The cornerstone of preventative treatment is preparation and anticipation of what excessive heat can inflict on the body and understanding who is most at risk. Enjoy what summer has to offer, but be aware of heat-related injuries and illnesses to prevent them from disrupting summer fun and celebrations.