Heat Illness

By: Dr. John Roberts

Since our temperatures are heading into the mid-80s this week, it’s time to start thinking about the dog days of summer. We will soon start to see patients suffering from heat illness coming in to urgent care and emergency departments.

Heat illness accounts for tens of thousands of visits to medical providers each year. Deaths from heat-related illness in America range from 300 to several thousand each year. Climate change appears to be a factor in the increasing number of severe heat waves in the U.S. and around the globe.

Risk factors predisposing a person to heat-related illness include being elderly, very young, or obese. Certain prescription and non-prescription drugs including antihistamines, beta blockers, diuretics, ADD/ADHD some psychiatric medications, and alcohol all increase the risk. Workers like firefighters who must wear heavy clothing are at very high risk.

Absorbing too much heat from the environment or producing too much heat internally leads to heat illness. Heat exhaustion and heat stroke are the two main types of heat illness.

Heat exhaustion is caused by excessive loss of body water and electrolytes. Heat exhaustion usually comes on slowly and is characterized by fatigue, weakness, nausea, vomiting, headache, muscle aches, cramping, dizziness, and irritability. Victims are usually pale, sweating profusely, have clammy skin and a weak, rapid pulse. Low blood volume from dehydration results in circulatory shock, reducing blood flow to critical organs.

The first thing to do for someone with heat exhaustion is to remove them from the hot environment. Standard treatment for shock should then be administered. Elevating the legs above the level of the chest helps get blood to the vital organs and brain. Sports drinks such as Gatorade® or PowerAde® are an excellent way to replace water and lost electrolytes.

If a victim shows signs of confusion or lethargy, or is not responding to treatment, rescuers should contact 911 or immediately take the victim to an emergency department. The prognosis for heat exhaustion is usually very good.

Heat Stroke is a different story. It is caused by malfunctioning temperature regulating mechanisms, resulting in an inability to transfer internal body heat to the environment. This can cause dangerously high internal body temperatures, sometimes as high as 105-106 ºF.

Symptoms of heat stroke usually come on rapidly and include headache, dizziness, fatigue, and weakness. Physical findings can include confusion, hot and dry skin, decreased sweating, rapid pulse, vomiting, loss of consciousness and occasionally seizures.

Heat stroke is a medical emergency requiring immediate medical care by calling 911. While waiting for EMS to arrive, remove the person from the hot environment and place the person in a bathtub or other tub filled with very cold water, preferably with some ice. Emergency services will usually observe the patient on-site until his or her core temperature has dropped below 102-103 ºF. If a tub is not available, place ice packs over the armpits, groin, neck and abdomen to help cool the patient down. Running a fan on the patient and spraying them with cool water can also be very effective in lowering their temperature.

As with most potential serious medical problems, prevention goes a long way. When you’re in the sun or a hot environment for an extended period, be sure to maintain your hydration. Water will do just fine unless you’re involved in intense physical activity for more than an hour. If that’s the case, consider adding in sports drinks. Salt tablets are not recommended.

You should drink roughly 16 ounces of fluid about two hours before outdoor activity if possible. Drink 4 to 8 ounces every 20 minutes during activity. A crude measure of adequate hydration is the color of your urine – clear or pale yellow is what you’re looking for.

Make sure young children and elderly family or friends stay out of the heat. Also make sure the elderly have a functioning cooling system in their home or apartment and that they have access to fluids.

If you take prescription medication, be sure to heed the warnings on the label or from your pharmacist to determine if it might affect your sensitivity to heat. Tell someone if you develop any of the symptoms outlined above and get to a cool environment immediately.

– Dr. John Roberts is a retired member of the Franciscan Physician Network specializing in Family Medicine