Heat Stroke (Heat Stroke)

What is Heat Stroke (Heat Stroke)?

Heat-related illnesses range from mild conditions like heat exhaustion to serious ones like heat stroke, which can be life-threatening. Heat stroke happens when the body’s temperature rises severely, typically above 40°C, but not always. It’s also characterized by signs of central nervous system problems such as unsteady walking, confusion, or seizures, usually following exposure to hot weather or intense physical activity. Factors that increase the risk of heat-related illnesses include environmental conditions, certain medications, drug use, and other existing health issues.

What Causes Heat Stroke (Heat Stroke)?

It’s crucial to determine where a patient falls on the spectrum of heat illness. Early signs of heat exhaustion can resemble other conditions, and may include symptoms like muscle cramps, tiredness, lightheadedness, nausea, vomiting, and headaches. However, if the condition worsens to the point of damaging internal organs, it evolves into heat injury. The presence of changes in mental status or behavior signifies the most severe form of heat illness known as heat stroke.

There are two types of heat stroke: classic and exertional. Classic heat stroke mostly impacts older people with existing health problems. On the other hand, exertional heat stroke tends to affect healthy individuals who participate in intense physical activities in hot or humid conditions.

Risk Factors and Frequency for Heat Stroke (Heat Stroke)

Understanding the public health effects of extreme heat can be challenging because doctors and other health care providers are not mandated to report heat-related illnesses. In the U.S., between 2006 and 2010, a minimum of 3,332 deaths were associated with heat stroke. It is, however, believed that the real numbers are likely much higher, as such cases are often under-reported. The risk of death due to heatstroke is connected to how much the body temperature has increased, how soon cooling measures are started, and the number of vital body systems that are disrupted.

Signs and Symptoms of Heat Stroke (Heat Stroke)

Heat stroke is a serious condition with a range of symptoms. Patients often have abnormal vital signs such as a high body temperature, rapid heart rate, fast breathing, widened pulse pressure, and low blood pressure—which is usually found in one-fourth of patients. Regular symptoms can also include weakness, tiredness, nausea, vomiting, dizziness, skin flushing or redness, crackling sounds in the lungs, reduced urination, excessive bleeding, and signs of issues with the nervous system.

There are two types of heat stroke: classic and exertional. In classic heat stroke, patients usually have hot and dry skin due to a lack of normal sweating, known as anhidrosis. On the other hand, in exertional heat stroke, which happens due to long periods of physical activity, lack of sweating is rare. Instead, these patients often experience prolonged sweating even after stopping the exercise.

High body temperature
Rapid heart rate
Fast breathing
Widened pulse pressure
Low blood pressure in some cases
Weakness
Tiredness
Nausea
Vomiting
Dizziness
Skin flushing or redness
Crackling sounds in the lungs
Reduced urination
Excessive bleeding
Signs of nervous system issues

Specific to heat stroke types:

Classic heat stroke: Hot and dry skin due to a lack of normal sweating
Exertional heat stroke: Prolonged sweating even after stopping the exercise

Testing for Heat Stroke (Heat Stroke)

If you think you may have heat stroke, doctors will check your vital signs often, measure your rectal temperature, and carry out various lab tests. These tests can include complete blood count (CBC), comprehensive metabolic panel (CMP), prothrombin time and partial thromboplastin time (PT/PTT), blood gases, and checks for creatine phosphokinase (CPK) in your blood and myoglobin in your urine. Depending on your symptoms, you might also need tests for drugs or other toxins, a chest X-ray, and an electrocardiogram (EKG).

An EKG may show changes in heart rhythms and signs of damage to the heart muscle. All patients with heat stroke will breathe quickly and have a fast heart rate. Levels of carbon dioxide (CO2) in the arteries often can drop below 20 mmHg, and about a quarter of patients can have low blood pressure. It’s also important for doctors to know all the medications a patient might be taking, especially water pills, beta-blockers, and anticholinergic medications.

In cases of classic heat stroke, patients may have respiratory alkalosis, a condition where there’s too little carbon dioxide in the blood. People with exertional heat stroke could also have lactic acidosis, where there’s too much lactic acid in the blood. The levels of electrolytes, which are minerals in your body that have an electric charge, can vary depending on whether someone has classic or exertional heat stroke.

Commonly in exertional heat stroke, there can be low calcium levels, increased phosphorus levels, and high potassium levels, which reflect muscle breakdown. Muscle breakdown or rhabdomyolysis is more common in exertional than classic heat stroke, and there tends to be a higher amount of CPK, a marker of muscle injury. In classic heat stroke, one can commonly see increases in AST and ALT, which are enzymes that indicate liver damage. Damage to the kidneys, liver or other organs can also occur in both forms of heat stroke.

Treatment Options for Heat Stroke (Heat Stroke)

Heat stroke treatment involves making sure the patient can breathe properly and has a good blood flow. The priority is to cool the patient down quickly while also treating any other damage to the body’s organs. Sometimes a patient might need to be put on a breathing machine if they’re very unconscious, but usually, they will start to wake up once their body temperature drops.

It’s really important to keep the patient hydrated but not to interfere too much if their sodium levels are off. Constantly checking the core body temperature with a rectal or throat probe is necessary. Once it drops to between 38 and 39 degrees Celsius, the cooling measures should stop. There’s no single best method for cooling a person down. Putting them in an ice bath can be the fastest way, but it might not be suitable for older people as it could over stimulate their hearts and cause agitation.

Cooling can also be done by applying ice packs to the armpits or groin or using a fan along with cool saline on the patient’s skin.

Medication can also be used to help with heat stroke. Dantrolene, a muscle relaxant, can help reduce heat for conditions like malignant hyperthermia, but it doesn’t improve the outcome for heat stroke patients. High-dose benzodiazepine might help to reduce shivering and decrease oxygen use, which could theoretically benefit patients, but heat stroke patients often can’t shiver. For this reason, it’s not typically recommended to use benzodiazepines for everyone, but it might be helpful for patients who are agitated or shivering. Antipyretics, commonly used to reduce fever, have no place in heat stroke treatment and can actually harm the liver.

When doctors are figuring out what might be causing symptoms like high fever, they might check for things like too many medications, poisoning, meningitis (brain inflammation usually caused by an infection), systemic infection (sepsis), certain serious medication reactions (neuroleptic malignant syndrome and serotonin syndrome), or even tropical diseases like malaria. To decide whether some of these possibilities are likely, doctors would review all the medications a person is taking to see if they could be causing problems.

However, some key indicators, like severe muscle stiffness or repeated muscle spasms, are typically not signs of heat stroke but they could point to serious medication reactions. Also, the doctor might ask about a person’s recent travels – especially if they have been to areas with high risk for malaria – and consider the specific types of malaria present in those regions.

Still, most people with high fever due to diseases like malaria, sepsis, or meningitis wouldn’t have the same high internal body temperature typically seen in heat stroke patients.

What to expect with Heat Stroke (Heat Stroke)

Heat stroke is a serious condition that can be fatal, but its mortality rate differs based on the cause. For instance, the mortality rate for heat stroke resulting from physical exertion is lower, ranging from 3% to 5%. However, ‘classic’ heat stroke, which does not result from physical exertion, has a significantly higher mortality rate ranging from 10% to 65%. This disparity is probably because classic heat stroke tends to affect older people with more health complications.

Importantly, if heat stroke victims are cooled down rapidly and effectively, survival rates can be significantly improved. In fact, there have been no reported fatalities amongst young patients with exertional heat stroke who were cooled down promptly.

Possible Complications When Diagnosed with Heat Stroke (Heat Stroke)

The effects of heat stroke can last beyond the initial disruption to the central nervous system (CNS). Damage can also occur to the gut, kidney, skeleton and other organs. Several complications can occur due to heat stroke such as:

Acute respiratory distress syndrome (severe difficulty breathing)
Disseminated intravascular coagulation (a condition that causes blood clots and bleeding)
Acute kidney injury
Liver injury
Low blood sugar (hypoglycemia)
Rhabdomyolysis (breakdown of muscle tissues)
Seizures

Even with successful cooling and body temperature reduction, many patients still show ongoing disruptions in body temperature and multiple organ dysfunction. Studies show that even reversible complications from heat stroke can take more than 7 weeks to get better completely.

Preventing Heat Stroke (Heat Stroke)

Preventing heat stroke is the most effective treatment. It’s crucial to regularly check in on older people, particularly those who don’t have air conditioning. Dressing in suitable clothes, not leaving kids alone in cars, and postponing intense activities in hot, humid weather can also help avoid heat stroke. If you start to notice signs of heat stroke, it’s a good idea to find a cool, shaded area. Medical professionals will typically start to cool down a patient diagnosed with heat stroke as quickly as possible while closely monitoring them. People who have had heat stroke because of physical exertion should avoid exercising for at least a week afterwards. Follow-up checks should be performed a week later to look for any damage to the body’s internal organs.

Frequently asked questions

Heat stroke is a condition where the body's temperature rises severely, typically above 40°C, and is characterized by signs of central nervous system problems such as unsteady walking, confusion, or seizures. It can be life-threatening and is usually caused by exposure to hot weather or intense physical activity.

Signs and symptoms of Heat Stroke (Heat Stroke) include: - Abnormal vital signs such as a high body temperature, rapid heart rate, fast breathing, widened pulse pressure, and low blood pressure (usually found in one-fourth of patients) - Weakness - Tiredness - Nausea - Vomiting - Dizziness - Skin flushing or redness - Crackling sounds in the lungs - Reduced urination - Excessive bleeding - Signs of issues with the nervous system Specific to the two types of heat stroke: - Classic heat stroke: Patients usually have hot and dry skin due to a lack of normal sweating, known as anhidrosis. - Exertional heat stroke: Patients often experience prolonged sweating even after stopping the exercise.

The doctor needs to rule out the following conditions when diagnosing Heat Stroke: 1. Medication reactions, including neuroleptic malignant syndrome and serotonin syndrome. 2. Poisoning. 3. Meningitis (brain inflammation usually caused by an infection). 4. Systemic infection (sepsis). 5. Tropical diseases like malaria. 6. Severe muscle stiffness or repeated muscle spasms, which could indicate serious medication reactions. 7. Other diseases like malaria, sepsis, or meningitis, which may cause high fever but typically do not have the same high internal body temperature as seen in heat stroke patients.

The types of tests that are needed for diagnosing heat stroke include: - Vital sign monitoring - Rectal temperature measurement - Complete blood count (CBC) - Comprehensive metabolic panel (CMP) - Prothrombin time and partial thromboplastin time (PT/PTT) - Blood gases - Creatine phosphokinase (CPK) level in blood - Myoglobin level in urine - Tests for drugs or other toxins - Chest X-ray - Electrocardiogram (EKG) In addition to these tests, it is important for doctors to know the medications a patient might be taking, especially water pills, beta-blockers, and anticholinergic medications. Depending on the symptoms and type of heat stroke (classic or exertional), additional tests may be needed to assess respiratory alkalosis, lactic acidosis, and levels of electrolytes such as calcium, phosphorus, and potassium. Enzymes such as AST and ALT may also be checked to assess liver damage.

Heat stroke is treated by ensuring proper breathing and blood flow, cooling the patient down quickly, and addressing any damage to the body's organs. In severe cases, a breathing machine may be necessary, but typically patients will start to wake up once their body temperature drops. Hydration is important, but caution should be taken if sodium levels are off. Monitoring core body temperature is crucial, and cooling measures should stop once it drops to between 38 and 39 degrees Celsius. Cooling can be achieved through methods such as ice baths, ice packs, or using a fan with cool saline on the skin. Medication, such as muscle relaxants or benzodiazepines, may be used in certain cases, but antipyretics should not be used as they can harm the liver.

The side effects when treating Heat Stroke can include: - Acute respiratory distress syndrome (severe difficulty breathing) - Disseminated intravascular coagulation (a condition that causes blood clots and bleeding) - Acute kidney injury - Liver injury - Low blood sugar (hypoglycemia) - Rhabdomyolysis (breakdown of muscle tissues) - Seizures These complications can occur due to the damage caused by heat stroke to various organs in the body. Even with successful cooling and body temperature reduction, patients may still experience ongoing disruptions in body temperature and multiple organ dysfunction. Reversible complications from heat stroke can take more than 7 weeks to fully recover.

The prognosis for heat stroke varies depending on the cause. Heat stroke resulting from physical exertion has a lower mortality rate, ranging from 3% to 5%. However, "classic" heat stroke, which does not result from physical exertion, has a significantly higher mortality rate ranging from 10% to 65%. Prompt and effective cooling of heat stroke victims can significantly improve survival rates, and there have been no reported fatalities among young patients with exertional heat stroke who were cooled down promptly.

You should see a medical professional, such as a doctor or healthcare provider, for heat stroke.

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