What is the hallmark symptom of heat stroke?

The hallmark symptom of heat stroke is neurologic dysfunction. This condition is characterized by an elevated body temperature, but the presence of neurologic symptoms such as confusion, altered mental status, seizures, or coma is what distinctly defines heat stroke. Neurologic dysfunction arises due to the severe hyperthermia and the resultant effects on the central nervous system.

While severe dehydration, high fever, and gastrointestinal symptoms may accompany heat stroke, they are not specific enough to diagnose the condition. Severe dehydration can occur in many heat-related illnesses, high fever can be indicative of various infections or other conditions, and gastrointestinal symptoms such as nausea or vomiting are common in many medical emergencies. The combination of hyperthermia and distinct neurologic impairment is critical in identifying heat stroke, distinguishing it from other heat-related conditions like heat exhaustion.