Heatstroke

What is heatstroke?

Heatstroke, also known as sunstroke, is the most serious of heat-related problems. Heatstroke often results from heavy physical activity in hot conditions, along with poor fluid intake. Normally, the body has a cooling system that is controlled by the brain to make the organs work properly. The cooling system adjusts and lowers body temperature by producing sweat. With heatstroke, the body's cooling system stops working and causes an increased body temperature. Normal body temperature for an adult is generally 37 degrees Celsius, or 98.6 degrees Fahrenheit. With heatstroke, the body temperature may reach more than 40 degrees Celsius, or 104 degrees Fahrenheit. As body temperature increases, it may start to damage the brain and other body organs. Heatstroke then leads to dehydration (loss of water and electrolytes) and life-threatening conditions, such as organ failure. Organ failure means your heart, brain, liver, or kidneys cannot work properly due to lack of oxygen.

What are the causes of heatstroke?

The following are possible causes and conditions which may increase your chance of having a heatstroke:

• Classic heatstroke: This occurs during exposure to a hot environment for a long period of time, without doing hard physical activity. Classic heatstroke may also happen in conditions that impair the body's cooling system. Any of the following may cause classic heatstroke:
  
  
  • High temperature conditions, such as heat waves during spring or early summer. Being closed in a hot environment, such as in deserts, cabins, or enclosed attics. Working in machinery or power plants, such as boiler rooms. Having no air conditioning system during high temperatures may further increase the chance of heatstroke.
    
    
  • Medical conditions, such as malnutrition (poor nutrition), diabetes (high blood sugar), kidney disease, heart failure or liver problems.
    
    
  • Medicines, such as those used in treating pain, depression, heart problems, or tumors. Use of illegal (street) drugs, such as cocaine, heroin, or amphetamines, may also impair your cooling system.
    
    
  • Older adults and very young children who depend on others for their food and liquid intake. Older adults and young children are unable to adjust quickly to high temperatures and weather changes.
    
    
  • Weighing more than what your caregiver suggests.
  
  
• Exertional heatstroke: Sweating a lot can make your body lose too much salt and water. This may cause your temperature to go up and cause exertional heatstroke. Exertional heatstroke may happen during any season, including winter. The following conditions may cause exertional heatstroke:
  
  
  • Heavy manual labor, such as working in constructions and mines.
    
    
  • Hard exercise over a long period of time.
    
    
  • Sporting events, such as marathons, triathlons, and bicycling.
    
    
  • Work demanding much physical effort, such as work in the military, fire department, and police force.

What are the signs and symptoms of heatstroke?

The signs and symptoms usually appear when dehydration starts. Muscle cramps caused by loss of salt from heavy sweating may happen first, and this may lead to heat exhaustion. Heat exhaustion occurs when water and minerals in your blood drop too low or too fast. Without treatment, heatstroke may follow and happen very rapidly. In severe cases, a sudden collapse during physical activity may result. You may also have one or more of the following:

• Body temperature reaching more than 40 degrees Celsius or 104 degrees Fahrenheit.
  
  
• Flushed (red) and very dry skin, or sweaty and cold, clammy skin.
  
  
• Headache, loss of consciousness (passing out), confusion, or trouble staying awake.
  
  
• Irregular or fast breathing, fast or pounding heartbeat, and low blood pressure.
  
  
• Muscle weakness and twitching, or a feeling of pins and needles on the skin.
  
  
• Nausea (upset stomach), vomiting, or abdominal (stomach) cramps.
  
  
• Seizures (convulsions) or coma.

How is heatstroke diagnosed?

Your caregiver will need to take your body temperature through your mouth, armpit, or anus (rear end). You may also need any of the following tests:

• Heart monitor: This test is also called an EKG or ECG. Sticky pads are placed on your skin to record your heart's electrical activity. An EKG gives information about how your heart is working. Lie as still as possible during the test.
  
  
• Blood and urine tests: Samples of your blood and urine are collected. These are sent to a lab for tests to check the levels of your salts and minerals.
  
  
• Blood gases: This is also called an arterial blood gas, or ABG. Blood is taken from an artery (blood vessel) in your wrist, arm, or groin. Your blood is tested for the amount of oxygen and carbon dioxide in it. The results can tell caregivers how well your lungs are working.

How is heatstroke treated?

Heatstroke needs to be treated as soon as possible. Treatment aims to quickly cool your body and prevent further problems. You may need any of the following:

• Cooling units: Different kinds of cooling units and materials may be used to rapidly decrease your body temperature. These include tubs filled with ice water, nets from where you will be sprayed with cold water, and cold sheets.
  
  
• Intravenous fluid: These are solutions of water that contain water, mineral salts, sugars, proteins. These may be given through your vein (IV) to increase your fluid volume.
  
  
• Medicines:
  
  
  • Alkalinizing agents: This class of medicine is made up of basic solutions that decrease the amount of acid in your blood and urine. Alkalinizing agents, such as sodium bicarbonate, also prevent formation of toxins (poisons) that may cause further damage to your kidneys.
    
    
  • Anticonvulsant medicine: This medicine is given to control seizures. Take this medicine exactly as directed.
    
    
  • Diuretics: These medicines, often called water pills, help decrease swelling in your brain and provide better blood flow. Diuretics also get rid of extra fluid in your legs and ankles, lungs, and around your heart. You may urinate more often when taking diuretics.
    
    
  • Vasopressors: These medicines make the blood vessels contract and raise your blood pressure.
  
  
• Respiratory support:
  
  
  • Oxygen: You may need extra oxygen if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask your caregiver before you take off the mask or oxygen tubing.
    
    
  • Ventilator: This is a machine that gives you oxygen and breathes for you when you cannot breathe well on your own. An endotracheal (ET) tube is put into your airway through your mouth or nose. You may need a trach if an ET tube cannot be placed. A trach is an airway tube put into an incision (cut) in the front of your neck. The ET tube or trach is attached to the ventilator.

What should I do if I think someone is having heatstroke?

• Move the person with heatstroke to a cool, shaded area and turn him on his side.
  
  
• Check if the person is breathing or has a pulse. Start rescue breathing and CPR (basic life support) if needed. Have someone call 911 immediately for medical assistance.
  
  
• If the person is awake and cold water is available, drench him with the water. You may also wrap him with water-soaked sheets. This may drop his body temperature rapidly. Give him cold liquids if he is able to drink.
  
  
• Remove his clothing and start fanning or spraying lukewarm water.
  
  
• Apply ice packs on the neck, armpits, and groin (area where the trunk and legs meet).
  
  
• Do not give fever medicines, such as acetaminophen and ibuprofen, to make the body temperature lower.

How can heatstroke be prevented?

You can do any of the following when exercising, or in a place with a very high temperature:

• Drink lots of liquids, such as water, fruit juices, or energy drinks, even if you do not feel thirsty. Avoid drinks that contain alcohol such as beer, wine, liquor, (vodka and whiskey), and other adult drinks.
  
  
• Eat salty foods, such as celery, saltine crackers, or pretzels.
  
  
• Limit your activities and strenuous exercises during the hottest time of the day. The hottest time of the day is usually late morning through early afternoon. Athletes may need to arrive at an event location 3 to 4 days before the event to adjust to the heat.
  
  
• Never leave children alone inside cars, especially during hot weather.
  
  
• Use air conditioners or fans, and have enough proper ventilation. If there is no air conditioning available, keep your windows open so that air may enter the rooms.
  
  
• Wear lightweight, loose, and light-colored clothing. Protect your head and neck with a hat or umbrella when you are outdoors.
  
  
• When planning your daily activities, check out the weather forecast first, especially if you need to work outdoors.

Where can I find more information?

Having heatstroke may be hard for you and your family. Contact the following for more information:

• American Academy of Family Physicians
  11400 Tomahawk Creek Parkway
  Leawood , KS 66211-2680
  Phone: 1- 913 - 906-6000
  Phone: 1- 800 - 274-2237
  Web Address: http://www.aafp.org
  

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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