How long does a high fever of 40°C pose a risk?
Disease description:
These two days while visiting my hometown, my wife somehow caught a cold and developed a fever. We only have some basic cold medicine, but it doesn't seem very effective. Her temperature feels extremely high, probably around 40°C. I'm wondering how long this fever can last before it becomes dangerous.
Doctor's answer (1)
Dr. Li Jingli
When a high fever reaches 40 degrees Celsius, the human body experiences an extremely uncomfortable state, with possible symptoms including weakness, headache, and dizziness. If the high fever persists for more than two hours, it may cause serious harm to the body.
Generally speaking, short-term high fever (e.g., within 24-48 hours), although uncomfortable, usually does not cause permanent organ damage. However, if the fever persists for more than three days or is accompanied by other severe symptoms (such as severe headache, confusion, or convulsions), it may damage the brain, heart, and other vital organs. Children and elderly individuals, as well as people with chronic diseases, have lower tolerance to high fever and are more prone to complications. A persistent high fever can significantly accelerate the basal metabolic rate, potentially causing symptoms such as rapid heartbeat, fast breathing, and generalized muscle pain. If fluids are not replenished promptly, patients may become dehydrated, which can lead to shock in severe cases.
Once a fever of 40 degrees Celsius occurs, immediate cooling measures must be taken and medical attention should be sought promptly to avoid irreversible damage to health.
