Heat illness in children

Massive heatwave in many areas around the world this week. In our area, we are sitting with heat index in the 90s.

Unfortunately, it is VERY easy to unknowingly become over-heated, especially when on vacation & not in your regular space or routine. Knowing the signs of heat illness & when to be concerned is important, especially because children and the elderly are especially vulnerable to heat injury.

What is heat illness?

When our bodies make too much heat, or are exposed to too much heat, they cannot adequately cool themselves down. This is what leads to over-heating. Humidity is also a problem — the mechanisms that our bodies rely on for cooling (such as evaporation) become less efficient. This is especially true when the temperature is >90-95 F (32-35 C) and the humidity is >75%.

Due to their anatomy and physiology, kids are at higher risk for overheating than adults. They absorb heat more in hot environments (due to the higher body surface area), they don’t sweat as efficiently, and they have a higher basal metabolic rate than adults - which means they need to be monitored especially closely in the heat.

The bottom line:

Heat illness is a spectrum - from minor reactions (such as heat rash, see separate post) all the way to heat stroke, which is very serious. Especially when heat index is >90F (>32C) be thoughtful about time outdoors. Kids are at high risk for overheating.

Prevention

There are a few important things you can to do prevent heat injury.

• Minimize time spent in temps >90F (eg outdoors/limit sporting activities in this weather, or in a hot car)

• Avoid sunlight during the hottest part of the day (10am - 3pm)

• Wear appropriate clothing (single layer of absorbed, loose fitting clothing in light colors, UPF 30-50). Layer methods of sun protection (sunscreen, hat, time in the shade, etc). Click here for product recommendations. Remember: sun protection is not the same as heat protection!

• Hydrate, hydrate, hydrate. Click here for dehydration information to watch for.

• Layer methods of sun protection (sunscreen, hat, time in the shade, etc)

Is heat injury serious?

Because heat injury lies on a spectrum, it can range from mild to very serious or even fatal. I like to think about it in four separate categories, as below.

Over-heating

Over-heating is the first stage of heat illness, and it is usually fairly mild. Especially in younger children, who may not be aware of the need to communicate if they’re feeling over-heated (or may be too young to do so), it is important to watch for non-verbal signs that they’re too hot. These can include:

• Flushing

• Sweating excessively

• Thirst

• Heat rash (see here for pictures and tips)

• Decreased urine output or other signs of dehydration

• Dizziness

• Core body temperature may or may not be elevated

What to do:

• Get out of the heat: go into natural shade, or an air conditioned room/car

• Rest and minimize further physical activity which will in turn minimize further heat production and stress on the body

• Consider touching base with your pediatrician if you're concerned, esp for younger infants

• Push electrolyte-containing fluids (see here for which are best and how much you need to give)

The Pediatrician Mom Tip: We do not recommend fever-reducing medications. the body is not over-heating because of a change in the “set-point” of the body temperature, which is what happens with you have a fever. So the fever-reducer will not decrease the body temperature. Additionally, because heat injury is associated with dehydration, the stress on the kidneys and liver when trying to metabolize medications like Acetaminophen or Ibuprofen may be increased.

Heat Cramps

Heat cramps are a result of dehydration and sweating that has led to electrolyte abnormalities. These changes will lead to the muscles seizing or cramping up. Some people don’t think of heat cramps as a different category, but I think it is a useful way to think about it as a red flag that things are moving past just being over-heated.

Many of the symptoms are similar to above, but in addition you may see muscles cramping up (especially large muscles such as the abdomen, arms or legs) or a sudden increase in fussiness from a young child.

What to do:

• In addition to the same interventions as above (under heat exhaustion), you can consider:

• Gentle massage of affected muscles

• Sometimes IV fluids are needed

Heat Exhaustion

Heat exhaustion is the next stage. At this point, the body has over-heated sufficiently that it can no longer cool itself down so many of the symptoms are going to be more serious.

Symptoms may include some of:

• The body temperature may be elevated, but likely is still going to be below 104F ( 40C)

• Rapid shallow breathing

• Rapid heart beat, sometimes the pulse can feel weak

• Muscle cramps

• Nausea or vomiting

• Heavy sweat

• Thirst

• More signs of dehydration including excess thirst and severe sweating. The skin many be hot or cold and clammy.

• Dizziness, headache, a sensation of light-headedness when standing

• Still relatively normal cognition, sometimes mild confusion but returns to normal quickly with cooling

What to do:

Seek medical care ASAP. In the meantime:

• Get out of the heat: go into natural shade, or an air conditioned room/car

• Rest/minimize further physical activity to minimize heat production

• Remove excess clothing

• Cool down quickly: cool bath/shower, spray, fan, cool packs to neck, groin, armpits

• Push cool electrolyte-containing fluids

• May need IV fluids, bloodwork, imaging, etc

The Pediatrician Mom Tip: Do NOT give fever-reducing medications.

Heat Stroke

This is the most extreme form of heat injury and is a result of the body no longer being able to control internal temperature. Normal measures to control temperature (such as sweating) no longer function, and the body temperature rises rapidly. This is very serious and potentially fatal, so these patients need emergent treatment.

Symptoms may include some or all of:

• Core body temperature is elevated, often above 104F (40C)

• Altered mental status (confusion, hallucinations, delirium, sometimes fainting/loss of consciousness)

• Rapid shallow breathing

• Rapid heart rate, weak pulse

• Nausea and vomiting

• Skin may be flushed or may be pale, cool and clammy

• Seizures

What to do:

Seek medical care ASAP. In the meantime:

• Follow the same measures as above under heat exhaustion.

• Do not give fever-reducing medication.

• These patients often need to be admitted to the ICU.

Heat injury is serious, but it is also preventable.

Make sure you keep an eye not just on your children, but also any elderly in your family or neighborhood, and pets.