How should heat illness be differentiated in the field?

• A. Heat stroke presents with altered mental status and very high core temperature; heat exhaustion has fatigue, dizziness, sweating but normal mental status
• B. Heat exhaustion presents with altered mental status and very high core temperature
• C. They are the same
• D. Heat exhaustion has altered mental status

Answer: (D)

Differentiating heat illness in the field relies on how the person’s brain is functioning and how hot they are. Heat stroke shows up with altered mental status—confusion, agitation, or even unconsciousness—and a very high core temperature. Heat exhaustion, on the other hand, causes symptoms like fatigue, dizziness, sweating, nausea, and generally preserves normal mental status without serious CNS changes. Because altered mental status signals brain involvement, it points to heat stroke rather than heat exhaustion. If you can measure temperature, a very high reading supports heat stroke, while a lower or normal reading fits heat exhaustion. In practice, treat heat stroke as an urgent cooling and medical emergency, aiming to bring core temperature down rapidly, while heat exhaustion requires cooling and fluids but is not as CNS-threatening. This framework helps you distinguish between the two quickly and act appropriately in the field.