Beth
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This was on ABC's news site......
Heat Exhaustion and Heat Stroke
Heat exhaustion develops when the body encounters excessively high temperatures that it is not used to managing. It occurs at body temperatures that are very high, but usually less than 40 degrees Celsius, or 104 degrees Fahrenheit. The symptoms of heat exhaustion are not very specific, but ultimately relate to a state of dehydration, which is the condition's primary characteristic. Symptoms may include weakness, headache, and nausea.
Heat stroke is severe injury from high body temperatures that causes damage to many organs, particularly the central nervous system, which include the brain and spinal cord. In contrast to heat exhaustion, patients suffering from heat stroke will have temperatures that are usually greater 104 degrees. Heat stroke may be divided into two categories-exertional and classic.
Exertional heat stroke
Exertional heat stroke patients are usually people who are exercising in excessively warm conditions. Their bodies cannot manage the stress of the physical activity and the hot environment together.
Classic heat stroke
Classic heat stroke patients are often elderly or debilitated people who are in warm environments for too long. The elderly are especially vulnerable to the heat, as the body is less and less able to handle heat as it ages. Elderly people may also have pre-existing illnesses that make them more susceptible to heat stroke, or they make take medications that affect the body's ability to manage hot temperatures. Elderly people, who, for economic reasons, are not able to get out of the heat, are at great risk for heat stroke.
Heat Transfer
In order to understand heat-related illnesses you need to know something about the way the body normally gets rid of heat. There are four ways the body transfers heat: radiation, evaporation, conduction, and convection.
Radiation
Radiation occurs when the body turns heat into electromagnetic waves. In other words, waves of heat can escape from the body directly into the surrounding air. This is the primary way that human beings are able to lose heat from their bodies in very hot environments.
Evaporation
Evaporation is the transfer of heat that occurs during the transformation of liquid to gas. Evaporation of sweat (even of sweat you cannot feel, called insensiblelosses) is another significant method that the body uses to cool down.
Convection and conduction
Convection and conduction are secondary ways for the body to lose heat after radiation and evaporation. Convection is the passage of heat into the air and into the vapor that surrounds the body. It is different from evaporation in that the heat does not transform to the gas phase, as it does in evaporation. Conduction is the transfer of heat through physical contact.
What Happens When it Gets Too Hot
In hot environments, the body initiates several processes to lose heat. First, the anterior hypothalamus, the body's thermostat in the brain, signals the body to open up blood vessels near the skin's surface so that heat can be transferred outside by the methods listed above. This vessel dilation is possible because blood is shunted away from the body's core. The hypothalamus also mediates sweating and tells the body to respond to the heat by taking off clothes and seeking a cooler environment.
When it becomes too hot, however, the body's ability to cool down becomes overwhelmed. Symptoms like fatigue, headache, muscle aches, confusion, and even coma can occur, depending on the severity of the condition.
This overwhelming of the body's means of handling heat can be caused by a very warm environment or excessive exercising in the heat, as discussed before. Also, though, patients may get overheated because of certain illnesses like hyperthyroidism (high thyroid hormone level) or infections causing fever. Additionally, some medications can cause high body temperatures. A class of drugs called anticholinergics can decrease the body's ability to sweat and, therefore, to lose heat. Other drugs called sympathomimetics can decrease skin vessel dilation. There are other classes of drugs that may also interfere with body temperature regulation through various, sometimes complicated, mechanisms.
Symptoms and Signs
There are a variety of symptoms associated with heat-related illnesses. Heat exhaustion patients may have vague complaints of symptoms that come on slowly. These can include:
Headache
Weakness
Lightheadedness
Muscle aches
Muscle cramps
Agitation
Heat stroke patients can have the same complaints as heat exhaustion patients, but they also suffer central nervous system problems, which can include:
Confusion hallucinations
Bizarre behavior
Seizure
Coma
It was once thought that heat stroke patients did not sweat, but this inability to sweat is variable, and often strikes the patient at the latest stages of the condition.
Heat stroke patients, because of the resulting multi-organ damage, may also complain of blood in the urine or stool, decline in the amount of urine produced and shortness of breath, among other problems.
Other symptoms
There are secondary categories of heat-related illnesses to watch out for:
Heat syncope occurs when a person overheats and then faints.
Heat cramps are muscle contractions associated with electrolyte or mineral abnormalities caused by the heat.
Heat edema is characterized by swelling in the arms and legs because of the heat.
Prickly heat is a heat rash that is red and very itchy.
Treatment
There is a lot that you can do for a person suffering from a heat-related illness. If you see someone who appears to be suffering from a heat-related illness, you should call for help immediately. In the most rare, severe cases, you should start cardiopulmonary resuscitation (CPR), if necessary. If the person is not a trauma patient (has not been in an accident, fight, or fall), you should move the individual from the hot environment to a cooler location. Next you can sprinkle lukewarm water on the skin and fan the patient; this will encourage evaporation. You can also apply ice packs to the neck, underarms, and groin.
In the emergency room
Once a patient has been taken to the emergency room, the cooling process will be continued. The doctor may use a cooling blanket and some other more aggressive methods, but in general, treatment is similar to the methods that should be initiated immediately, including fanning and ice packs.
The doctor may order tests to assess organ damage. These tests can include electrolytes or minerals, blood-clotting tests, a urine analysis, creatine phosphokinase (a muscle enzyme quantification), and a head computed tomography (CT or cat) scan. Heat stroke patients are admitted to the intensive care unit. Heat exhaustion patients are admitted to a regular floor bed in the hospital. When patients are released from the hospital, they should have a place to go to avoid the heat, and they must be able to rehydrate themselves.
If caretakers are aggressive with these cooling techniques before delivering the patient to the hospital, and the emergency department is able to treat any related organ damage, then there is a good possibility that the prognosis will be excellent.
Prevention
Heat-related illnesses are often preventable. When hot weather is expected, the elderly and debilitated must be ensured access to cool, air-conditioned shelter. People should be encouraged to wear light-colored, loose clothing and bathe in tepid water. Also, hydration is critical, and people in hot weather should increase their fluid intake substantially.
To avoid exertional heat stroke, athletes should not exercise in extreme heat, and coaches should be aware of the symptoms of heat-related illnesses. Athletes also must stay well-hydrated.
Summary
Heat-related illnesses are a continuum of conditions but have traditionally been divided into heat exhaustion-characterized by dehydration-and heat stroke, in which organs, particularly the central nervous system, are damaged. Heat exhaustion patients may have vague complaints like weakness, nausea and headache, whereas heat stroke patients often have these symptoms plus confusion or hallucinations. Heat-related illnesses present a potentially severe-even fatal-set of conditions that can often be prevented if treated early and aggressively. Learning about the symptoms and preventive care can help you help someone else.
Heat Exhaustion and Heat Stroke
Heat exhaustion develops when the body encounters excessively high temperatures that it is not used to managing. It occurs at body temperatures that are very high, but usually less than 40 degrees Celsius, or 104 degrees Fahrenheit. The symptoms of heat exhaustion are not very specific, but ultimately relate to a state of dehydration, which is the condition's primary characteristic. Symptoms may include weakness, headache, and nausea.
Heat stroke is severe injury from high body temperatures that causes damage to many organs, particularly the central nervous system, which include the brain and spinal cord. In contrast to heat exhaustion, patients suffering from heat stroke will have temperatures that are usually greater 104 degrees. Heat stroke may be divided into two categories-exertional and classic.
Exertional heat stroke
Exertional heat stroke patients are usually people who are exercising in excessively warm conditions. Their bodies cannot manage the stress of the physical activity and the hot environment together.
Classic heat stroke
Classic heat stroke patients are often elderly or debilitated people who are in warm environments for too long. The elderly are especially vulnerable to the heat, as the body is less and less able to handle heat as it ages. Elderly people may also have pre-existing illnesses that make them more susceptible to heat stroke, or they make take medications that affect the body's ability to manage hot temperatures. Elderly people, who, for economic reasons, are not able to get out of the heat, are at great risk for heat stroke.
Heat Transfer
In order to understand heat-related illnesses you need to know something about the way the body normally gets rid of heat. There are four ways the body transfers heat: radiation, evaporation, conduction, and convection.
Radiation
Radiation occurs when the body turns heat into electromagnetic waves. In other words, waves of heat can escape from the body directly into the surrounding air. This is the primary way that human beings are able to lose heat from their bodies in very hot environments.
Evaporation
Evaporation is the transfer of heat that occurs during the transformation of liquid to gas. Evaporation of sweat (even of sweat you cannot feel, called insensiblelosses) is another significant method that the body uses to cool down.
Convection and conduction
Convection and conduction are secondary ways for the body to lose heat after radiation and evaporation. Convection is the passage of heat into the air and into the vapor that surrounds the body. It is different from evaporation in that the heat does not transform to the gas phase, as it does in evaporation. Conduction is the transfer of heat through physical contact.
What Happens When it Gets Too Hot
In hot environments, the body initiates several processes to lose heat. First, the anterior hypothalamus, the body's thermostat in the brain, signals the body to open up blood vessels near the skin's surface so that heat can be transferred outside by the methods listed above. This vessel dilation is possible because blood is shunted away from the body's core. The hypothalamus also mediates sweating and tells the body to respond to the heat by taking off clothes and seeking a cooler environment.
When it becomes too hot, however, the body's ability to cool down becomes overwhelmed. Symptoms like fatigue, headache, muscle aches, confusion, and even coma can occur, depending on the severity of the condition.
This overwhelming of the body's means of handling heat can be caused by a very warm environment or excessive exercising in the heat, as discussed before. Also, though, patients may get overheated because of certain illnesses like hyperthyroidism (high thyroid hormone level) or infections causing fever. Additionally, some medications can cause high body temperatures. A class of drugs called anticholinergics can decrease the body's ability to sweat and, therefore, to lose heat. Other drugs called sympathomimetics can decrease skin vessel dilation. There are other classes of drugs that may also interfere with body temperature regulation through various, sometimes complicated, mechanisms.
Symptoms and Signs
There are a variety of symptoms associated with heat-related illnesses. Heat exhaustion patients may have vague complaints of symptoms that come on slowly. These can include:
Headache
Weakness
Lightheadedness
Muscle aches
Muscle cramps
Agitation
Heat stroke patients can have the same complaints as heat exhaustion patients, but they also suffer central nervous system problems, which can include:
Confusion hallucinations
Bizarre behavior
Seizure
Coma
It was once thought that heat stroke patients did not sweat, but this inability to sweat is variable, and often strikes the patient at the latest stages of the condition.
Heat stroke patients, because of the resulting multi-organ damage, may also complain of blood in the urine or stool, decline in the amount of urine produced and shortness of breath, among other problems.
Other symptoms
There are secondary categories of heat-related illnesses to watch out for:
Heat syncope occurs when a person overheats and then faints.
Heat cramps are muscle contractions associated with electrolyte or mineral abnormalities caused by the heat.
Heat edema is characterized by swelling in the arms and legs because of the heat.
Prickly heat is a heat rash that is red and very itchy.
Treatment
There is a lot that you can do for a person suffering from a heat-related illness. If you see someone who appears to be suffering from a heat-related illness, you should call for help immediately. In the most rare, severe cases, you should start cardiopulmonary resuscitation (CPR), if necessary. If the person is not a trauma patient (has not been in an accident, fight, or fall), you should move the individual from the hot environment to a cooler location. Next you can sprinkle lukewarm water on the skin and fan the patient; this will encourage evaporation. You can also apply ice packs to the neck, underarms, and groin.
In the emergency room
Once a patient has been taken to the emergency room, the cooling process will be continued. The doctor may use a cooling blanket and some other more aggressive methods, but in general, treatment is similar to the methods that should be initiated immediately, including fanning and ice packs.
The doctor may order tests to assess organ damage. These tests can include electrolytes or minerals, blood-clotting tests, a urine analysis, creatine phosphokinase (a muscle enzyme quantification), and a head computed tomography (CT or cat) scan. Heat stroke patients are admitted to the intensive care unit. Heat exhaustion patients are admitted to a regular floor bed in the hospital. When patients are released from the hospital, they should have a place to go to avoid the heat, and they must be able to rehydrate themselves.
If caretakers are aggressive with these cooling techniques before delivering the patient to the hospital, and the emergency department is able to treat any related organ damage, then there is a good possibility that the prognosis will be excellent.
Prevention
Heat-related illnesses are often preventable. When hot weather is expected, the elderly and debilitated must be ensured access to cool, air-conditioned shelter. People should be encouraged to wear light-colored, loose clothing and bathe in tepid water. Also, hydration is critical, and people in hot weather should increase their fluid intake substantially.
To avoid exertional heat stroke, athletes should not exercise in extreme heat, and coaches should be aware of the symptoms of heat-related illnesses. Athletes also must stay well-hydrated.
Summary
Heat-related illnesses are a continuum of conditions but have traditionally been divided into heat exhaustion-characterized by dehydration-and heat stroke, in which organs, particularly the central nervous system, are damaged. Heat exhaustion patients may have vague complaints like weakness, nausea and headache, whereas heat stroke patients often have these symptoms plus confusion or hallucinations. Heat-related illnesses present a potentially severe-even fatal-set of conditions that can often be prevented if treated early and aggressively. Learning about the symptoms and preventive care can help you help someone else.
