What is a critical sign of heat stroke?

Altered mental status is a critical sign of heat stroke, indicating a severe level of hyperthermia and the potential for central nervous system dysfunction. As the body temperature rises above normal, typically exceeding 40 degrees Celsius (104 degrees Fahrenheit), the brain can begin to be affected, leading to confusion, agitation, delirium, or even loss of consciousness. This alteration in mental status signifies that the individual is not merely experiencing heat exhaustion but has progressed to a potentially life-threatening condition requiring immediate medical intervention.

In heat stroke, other signs such as excessive sweating may be present in earlier stages like heat exhaustion, but as the condition progresses and the body’s thermoregulatory processes fail, sweating may diminish. A core body temperature below 40 degrees Celsius does not align with the diagnostic criteria for heat stroke as it indicates that the individual has not yet reached the critical level associated with the condition. Similarly, dizziness and headaches can occur in both heat exhaustion and heat stroke but do not represent the severe systemic changes that altered mental status does. Therefore, recognizing altered mental status is essential for promptly identifying and treating a heat stroke situation.