What is the hallmark sign of heat stroke?

• A. Hypotension
• B. Neurologic dysfunction with cerebral edema
• C. Rash
• D. Nausea

Answer: (B)

Heat stroke is defined by extreme hyperthermia with failure of the body's cooling mechanisms, and the hallmark sign is neurologic dysfunction caused by brain involvement. This means sudden changes in mental status—from confusion and agitation to seizures or coma—often with evidence of cerebral edema in severe cases. The central nervous system impact is the defining feature that sets heat stroke apart from milder heat illnesses.

Other symptoms like rash, nausea, or low blood pressure can occur in various illnesses or as secondary effects, but they do not pinpoint heat stroke the way altered consciousness or seizures do. Recognizing CNS signs quickly is crucial because it signals the need for rapid cooling and aggressive supportive care to prevent irreversible brain injury.