Q: Is bringing your temperature down important when you have a fever?
A: Probably not. Treating a fever seems to hinder recovery from infections.
Our expert: Dr Paul Young (31/07/2012)
What do you do when you have a fever? Conditions of UseYou're achy and lethargic. Your muscles shake. You get chills one minute and are on fire the next.
Having a fever feels horrible and chances are you will try to bring your temperature down – either with medicine, like paracetamol, or other measures, such as tepid baths, stripping off clothing and blankets, lying under a fan and so on. But do you actually need to treat a fever? Probably not in most cases, says Dr Paul Young, an intensive care specialist at Wellington Hospital in New Zealand and fever researcher. In fact, it might be important to leave a fever alone.While quality research has been lacking, there's some evidence that shows reducing a fever actually hinders recovery from infections, the cause of most fevers in the community, Young says. But whether slowing down your recovery is an issue might depend on how sick you are. For mild illnesses like colds, "if it takes you one day longer to get better but you felt better throughout the illness then it might be worth it," Young says. Also, if you take paracetamol to lower a fever, it may make you feel better because it also acts as a painkiller. (Whether lowering a fever in itself makes you feel better isn't clear.) But when you're critically ill, some evidence suggests treating a fever might make it less likely you'll survive."At the moment, we use paracetamol all the time. It's given to more than half of patients in intensive care units on any given day and yet, we don't know if the fact it reduces temperature is a bad thing."We don't know where the balance of risks and benefit lies at the moment."
Fabulous fever?
The frightening idea that treating a fever might sometimes kill people stems from a study in which Young was involved, published in the journal Intensive Care Medicine earlier this year.It looked at over 600,000 intensive care patients and showed that in those with infections, the higher the fever in the first 24 hours after admission, the lower the death rate."There's a cost that comes with having a fever," says Young. "You tend to have a higher heart rate, you tend to breathe faster and the metabolic demands on your body are generally increased. In the absence of infection this might be a bad thing. But if you have an infection, the fever seems to help kill the bugs."Whether leaving a fever alone could make the difference between life and death is being tested in a follow-up study. The results should be available in 2015.
Body of evidence
The idea fever is helpful in fighting infections isn't new, however. Before antibiotics were invented in the late 19the century, therapies based on fever were widely used.Demonstration of the fact that fever from malaria could cure paralysis caused by the sexually transmitted infection, syphilis, was the basis of a Nobel Prize in 1927."We've come full circle," Young says. He is not sure why it is now more routine to treat fevers, but says it doesn't seem to be based on evidence and may relate to the development and marketing of drugs.More recently, it's been shown treating fever: increases death rates from infections in animalsworsens nasal symptoms in children with coldsprolongs blisters in children with chickenpoxblunts the immune response triggered in children in response to vaccinations."Basically everything that's more evolved than a cartilaginous fish gets a fever when they get an infection. For it to have evolved and been preserved across all of biology without having a [useful] purpose would be very unusual."
Fever fits
One reason we try to bring a fever down is fear the temperature will keep rising and cause damage to the brain and other organs.It's true that temperatures over 41 degrees Celsius can be harmful but such high fevers usually occur only with events like heat stroke, where our ability to regulate temperature is disrupted.In contrast, fevers from infections happen because they trigger a resetting of the "thermostat" in our brains. In general, this probably causes our bodies to "mount a response aimed at raising our temperature only to a level that's needed to kill the bugs," Young says."After that, the fever will go away. I think there's very little evidence [infections from fevers] will keep getting higher and higher or that the fever in and of itself will be harmful."However, high fevers from infections can cause fits or seizures (also known as febrile convulsions) in about 5 per cent of children. (Check out our Fact File: Fever for more.) But Young says there isn't evidence that treating fevers reduces the risk of febrile convulsions. Attempting to bring a fever down rapidly, say in a cold both, can actually trigger a seizure, says Clinical Professor Dominic Fitzgerald, a paediatric respiratory specialist at The Children's Hospital, Westmead in Sydney, Australia.Says Young: "if you've got an infection, my gut feeling is that it's not important to treat the temperature but I don't think we have proof of that yet. What I can say is that using paracetamol and other drugs to treat temperature in the way they're used commonly is not based on anything other than experience."There's no reason to suspect leaving the temperature to go up would be bad in terms of your ability to fight infection and there's a lot of data to suggest it's probably often a good idea."For tips on making someone with a fever more comfortable, or when a fever warrants calling a doctor, see our Fever Fact File.The Australian organisation that aims to promote quality use of medicines, NPS, also acknowledges fever helps fight infection. It says medicine to lower a fever can be given to children with a temperature higher than 38.5 degrees Celsius if they are "uncomfortable or miserable" but adds "the aim is not to bring their temperature back to normal".The Royal Children's Hospital in Melbourne also has a useful factsheet on fever in children.
Notes: Dr Paul Young is a fever researcher and intensive care specialist at Wellington Hospital in New Zealand. He spoke to Cathy Johnson.
(source: website)
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