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Heatstroke, also known as sunstroke, is a life-threatening condition that occurs when the body temperature exceeds 104 degrees F (40 C). This most extreme form of hyperthermia or heat-related illness is typically due to extended exposure to high temperatures or physical activity in hot and humid environments.
Heatstroke can lead to serious consequences such as brain damage, organ failure, or fatality by causing the body to overheat. The condition may manifest with symptoms such as confusion, seizures, or loss of consciousness. It is during summertime that this condition is the most frequent.
Symptoms
Heatstroke is a critical medical condition. Its signs and symptoms may include:
- Elevated body temperature: The primary indicator of heatstroke is a core body temperature reaching 104 F (40 C) or higher, measured with a rectal thermometer. This may include hot, flushed skin or notably pale skin.
- Anhidrosis: Or absence of sweating, especially prevalent in non-exertional heatstroke.
- Unusual and persistent sweating even after discontinuing physical activity, which is more frequent in exertional heatstroke.
- Ataxia: Heatstroke can lead to difficulties with movement and coordination.
- Altered mental state or behavior: Heatstroke may lead to confusion, agitation, slurred speech, irritability, delirium, seizures, and even coma.
- Nausea and vomiting: Individuals experiencing heatstroke may exhibit vomiting or feel nauseous.
- Audible lung crackles: Such as bubbling or gurgling sounds in the lungs.
- Rapid breathing: Heatstroke can cause breathing to become quick and shallow.
- Tachycardia: Or accelerated heart rate as the heart works intensely to aid in cooling the body under heat stress.
- Headache: Heatstroke may lead to a throbbing sensation in the head.
- Oliguria, or low urine output
- Seizures
- Syncope (fainting) or loss of consciousness.
- General weakness.
If heatstroke is suspected, urgently seek medical help, and make efforts to quickly reduce the individual’s body temperature.
Immediate steps to cool the individual may include moving them into the shade or indoors, removing excess clothing, and employing various means to cool them down, such as placing them in a cool tub of water, using a cool shower, or applying ice packs or cold, wet towels to their head, neck, armpits, and groin.
Causes
Heatstroke occurs when the body’s natural cooling mechanisms fail to adequately regulate its temperature. Typically, the hypothalamus, a crucial part of the brain responsible for regulating bodily functions, maintains the core body temperature at approximately 98.6°F (37°C). However, if the body absorbs more heat than it can dissipate, the internal temperature surpasses this normal level, resulting in heatstroke.
Heatstroke can occur in two main ways:
- Hot environment exposure: This type is more common in older adults and those with chronic illnesses. In nonexertional or classic heatstroke, being in a hot environment, especially in hot and humid weather for a long time, causes a rise in body temperature.
- Strenuous activity: This type is more likely to happen to people who are not accustomed to hot weather or conditions. Exertional heatstroke results from intense physical activity in hot weather, affecting anyone exercising or working in high temperatures.
In both types of heatstroke, the condition can be triggered by factors such as wearing excessive clothing, consuming alcohol that affects the body’s temperature regulation and becoming dehydrated due to insufficient water intake.
Risk factors
Heatstroke can occur to any person at any age. However, certain factors make a person more susceptible to heatstroke, such as:
- Age: Infants and the elderly faces a higher risk due to potential difficulties in regulating body temperature. The inability of both age groups to stay hydrated typically raises risk. The central nervous system is not fully developed in babies and toddlers, and it starts to degrade in individuals over the age of 65.
- Sudden exposure to hot weather: People who experience an abrupt rise in temperature, such as a trip to a hotter region or that of an early summer heat wave, may be more vulnerable to heat-related illnesses.
- Exertion in hot environments: Individuals engaged in physically demanding activities in hot environments, like athletes, soldiers, or those with strenuous occupations, are more susceptible to heatstroke. Reduce physical activity for a few days to let the body adjust to the new conditions. However, be aware that the risk of heatstroke may remain elevated until one been exposed to higher temperatures for several weeks.
- Inadequate air conditioning: Air conditioning is the best way to cool down and reduce humidity when it is extremely hot outdoors.
- Certain drugs: Stimulants used for attention-deficit/hyperactivity disorder (ADHD) and illegal stimulants like amphetamines and cocaine can increase susceptibility to heatstroke. Generally, the use of medications like diuretics, sedatives, vasoconstrictors, tranquilizers, beta blockers, antidepressants or antipsychotics, or heart and blood pressure medications that impact temperature regulation elevates one’s risk.
- Certain diseases: Conditions that may affect sweat production include cystic fibrosis, and various medical conditions related to the heart, lungs, kidneys, liver, thyroid, or blood vessels can elevate the risk. Risk also increases among people having a high fever, obesity, or a heatstroke history.
Diagnosis
The diagnosis of heatstroke usually involves examining the symptoms, conducting a physical evaluation, and measuring body temperature.
Laboratory testing may be required to help confirm the diagnosis, rule out other possible causes of the symptoms, and evaluate organ damage. Tests that may be ordered include:
- Rectal temperature: Compared to oral or forehead thermometer, this method is more precise of taking the core temperature of the body.
- Blood tests: To determine whether the central nervous system has been affected, this test may be required. It can determine the amount of gases in the blood, as well as the sodium and potassium levels.
- Urinalysis: This can determine whether the kidney function was impacted by heatstroke. Generally, this is done to determine whether one has a heat-related illness based on the color of the urine, which is often darker.
- Electrocardiogram (EKG): This could be performed to monitor heart electrical activity.
- Tests of muscular function: Rhabdomyolysis can occur following a heatstroke. This test can look for signs of severe muscle tissue injury.
- Imaging tests: Such as X-rays, are performed to look for internal organ damage.
Treatment
Prompt medical intervention is crucial in the treatment of heatstroke. The primary focus is on rapidly cooling the body to prevent or reduce potential damage to the brain and vital organs. Healthcare professionals discontinue cooling procedures once the body temperature stabilizes at approximately 102°F (38.9°C). The length of hospital stay varies depending on the severity of the heatstroke and the condition of the organs.
Treatment options typically include:
- Immersion in cold water: There is a lower chance of fatalities and organ damage the faster a person is soaked in cold water. Research has shown that the fastest way to reduce the body’s core temperature is to take a bath in cold or ice water.
- Use of ice and cooling blankets: The body core temperature can be lowered by using special cooling blankets and applying ice packs to specific areas like the groin, neck, back, and armpits.
- Evaporation cooling techniques: The procedure involves misting cool water on the body while warm air is fanned over, promoting evaporation and skin cooling.
- Administering medications: To prevent shivering, which can increase body temperature and hinder the effectiveness of treatment, muscle relaxants such as benzodiazepines may be administered.
- Cold-water lavage. The procedure involves putting cold water into body cavities using catheters. This helps lower the overall body temperature, with catheters inserted into the rectum or down the throat.
