Resource Highlights: Fever

[music, with snippets]

Alasdair: Fever is a normal physiological response to an infection, and then if you're able to explain that to parents, you will change their whole perception.

Emma: Fever makes parents scared, they fear fever.

Alasdair: Make hand washing great again, that's my new motto!
[music ends]

Emma: Hello, and welcome to The Paeds Round. This is a regular podcast and the Royal College of Paediatrics and Child. Health, and focuses in on key issues impacting child health. I'm Emma Lim, a consultant paediatrician and as ever, I'm here with my colleague Christo Tsilifis, and we're coming to you from the Great North Children's Hospital in Newcastle upon Tyne, and every month we invite experts to bring you important educational learning points. So, let's get into today's Paeds Round!
I'm very excited today to have a guest from down south, Alasdair Munro! So hello Alasdair.

Alasdair: Hello, thank you so much for having me on, what a pleasure it is.

Emma: I've always been a big fan of yours for two reasons. Number one, we have a rule in our house that you can argue any point you like, as long as you have the evidence to back it up. So that's one of my big fan points. And number two, I always think if people have good ideas, but they don't tell anybody about them, there is no point having that idea. And I think it's so underrated the way we use social media and the way we put out important messages. And I think as paediatricians, we're really bad at this.

Alasdair: Well, thank you so much, that's a very kind thing to say. And I agree, I think the problem is that paediatricians often very humble and feel that they couldn't possibly have anything useful to add. If I know this, surely everyone knows this. But, as it turns out, there's lots of good stuff to learn, it's great to share it. As soon as you start sharing it, you realise that lots of people want to hear a lot of it and it's not all quite as obvious as sometimes we tell ourselves. So yeah, good to get the knowledge out there, I guess.

Emma: We did miss a really important point, because you didn't actually tell us what you do and where you come from.

Alasdair: Oh yes, let me tell you. I'm a paediatric registrar down in the South of England. I'm currently out of programme, working as a senior clinical research fellow in paediatric infectious diseases. I'm working in the NIHR (National Institute for Health and Care Research) clinical research facility in Southampton, and I've been doing my PhD. It was a very interesting time to be doing a PhD, because I wasn't very far in when COVID derailed the whole thing, but it's been it's been somewhat to my advantage as well. I've had some wonderful opportunities, working in vaccine science in the pandemic has been quite something else. My interest is obviously infections in children, and I do my clinical shifts in the emergency department, so most of my clinical work is primary care. So I’m seeing a lot of the bread and butter paediatric stuff, and I have a real passion for making sure that we can get that stuff as good as we can do.

Emma: And as always, I have Christo with me.

Christo: Yes, thank you very much Emma. I am Christo, I'm a clinical research fellow in Newcastle, in the final year of my PhD. I work closely with Emma in general paediatrics and infectious diseases, so it's really great to be able to have Alasdair with us. And I think you mentioned before that there are various ways in which you've tried to communicate various gems about general paediatrics infection. Where are some of the places that we can read more about some of the articles you've put out?

Alasdair: Oh thanks for asking Christo, allow me a minute to plug my material, thanks! So I use Twitter, the social media platform quite a lot, and you can find me through the tag @apsmunro and I tweet and share a lot of my stuff on there. I also have a newsletter on Substack. I can't remember the URL for that, but if you go to my Twitter the link is in the bio. And some of my old stuff is also on Don't Forget the Bubbles, which I'm sure most paediatricians will be aware of. But if you're otherwise involved in child health, and you're not aware, just Google ‘don't forget the bubbles’. It's an absolute treasure trove of clinical paediatric resources. And yes, some of my earlier blogs on there are still online. So that's where you can, go check it out. Some of them might be good!

Emma: Honestly, I think he must have paid you earlier!

Christo: We’ll have links to all of this in the show notes.

Emma: So let's get down to business. This is a really interesting topic because we all think we know quite a lot about fever, but we often don't answer the questions that parents really want to know. So I'm going to start at the beginning and this is a question that Christo put to me. What is fever? What is the definition of fever and what is normal?

Alasdair: Glad we can start with a very uncontroversial topic. Well, thanks for easing us in there!
What is a fever? Well, it's completely arbitrary in some senses, I guess we use it to indicate a raised body temperature outside of the normal limit, usually in response to an infection, but not always. And when does raise temperature become a fever? Now in the UK, I guess we would say usually above 38 degrees centigrade, some people would go even higher and say 38.5, the really hardcore people would cut it off there. But it's because we don't really know precisely what the normal range of temperature is and it's all based on sort of historical data that’s not quite as certain as it should be. In fact, it's amazing how many normal ranges if you go back far enough looking for the beginning end up this way! But we would normally say a normal temperature is somewhere between 36.5 degrees and
37.5 degrees. And then there's this beautiful grey area where everyone disagrees on what the temperature between the 37.5 and 37.9 means. And then I think most people would agree that from 38 onwards, that is a fever or a raised temperature.

Emma: One of the things that interests me, and I think people don't think about this enough, is that you can be really sick with a bad infection and no fever. And you can also have a very high fever and not really be that unwell.

Alasdair: Yeah, I think there's a lot of stuff about fevers that intuitively we feel should be true. And then when you look at the data, actually, it's not true. So, things like if the fever is really high, as you said, this must be a sign that the child is more ill. And actually, the predictive value of the higher the temperature is so poor as to be almost useless.

Emma: So Alasdair, that's such an important point. We always get parents coming in saying, ‘my child had a fever, they must be really ill.’ And you're telling me there is no good evidence linking high temperatures to an increased risk of a serious bacterial infection or any other serious infection?

Alasdair: That's right. We talk about these things having a predictive value, so how likely is a really high temperature to predict a serious infection, and outside of children who are really high risk of having a serious illness like those with immunodeficiency, in otherwise healthy children the higher the temperature is basically of no value. So once they've crossed the threshold for a fever, it's a fever, how high it was is not really that important. As much as it feels like it should be to parents and often to doctors as well.

Christo: So knowing that the height or the grade of a fever doesn't necessarily predict the likelihood of serious illness. Are there any physiological changes that go along with this that we might see in clinical practice?

Alasdair: Yes, there are. So, we know that the height of a temperature is correlated to the change in heart rate, in particular. We always used to think it was respiratory rate too, some degree that's probably true, but actually the most up to date evidence would suggest respiratory rate is much less affected by the height of the fever, but heart rate certainly. Now of course, this is the cause of a huge amount of anxiety and time spent, particularly in the emergency department. Because one of the things we always say we like to see is that temperature when it does normalise or comes down, that the heart rate starts following it down too. So of course we're all on the lookout for abnormal heart rates and things because they're all over our sepsis tools, as another trigger warning tool. But because we know it can be normal, it makes it really difficult in clinical practice for paediatricians to try and make sure people feel reassured and the documentation obviously looks complete and that you've done all the right things to check it all out.

Christo: I think this is a really interesting paradox that we know that fever changes your physiological observations. We are happy with the idea that response to fever to antipyretic doesn't necessarily predict how serious the illnesses is. Yet, we do feel uncomfortable seeing a child with a heart rate of 160, who is febrile who otherwise looks well, and discharging them from the emergency department without a longer period of observation or seeing those observation normalise. I think it's one of those kinds of big problems, and Emma has previously talked about trying to identify sepsis being like looking for needles in a haystack. And I think this kind of epitomises that.

Alasdair: Yeah, it does. And I guess the problem is, is that a lot of it does come back to where there's been bad outcomes for children, very often there'll be this retrospective look back and it's combing through all the details to see anything that could have picked up that the child was ill. And because the abnormal heart rate is so common, it very commonly gets picked up in these retrospective reviews and then gets implemented as a learning point. And people really feel like they can’t discharge children with abnormal heart rate, in case this is the one in a million children who does end up coming back very seriously unwell, which could not be detected at that first point. But this is one of the concerns that weighs very heavily on health care providers, particularly in paediatrics.

Emma: I am burning, burning issues with all these normal values. I'm getting I'm going to get it all out now!
First of all, one of my issues is that a lot of paediatric normal values were based on very small populations, so the original data. And we have a lot of new data with electronic observations, but it hasn't yet been incorporated into practice. So that's number one.
Number two, I think you're completely right about people looking at all the children who got very sick and then looking back and saying that's the problem. Actually, we should be looking at all the children who well, So there was a really good study by Winter, who looked at 33,000 children that were discharged with abnormal and normal paediatric early warning scores. Very few, it was like less than 1%, had any abnormal outcomes. So, the majority of children are safe to send home. That is the message that people need to know. If you have a fever, you get checked over and the parents are happy and reassured, you're more or less safe to send them home.

Alasdair: I agree, and I think it's one of the things that we struggle with isn't it. We all know that that's true, and in practice, it's so frustrating feeling like you can't do that, because were someone to look back they won't see all the other children who went home. They don't see how the heart rate is in normal in every child you see and the difficulty is that that makes sense to manage a busy department.

Christo: Yes, so I think you mentioned earlier that there are some special patient groups outside of the general paediatric population, where actually the presence of fever or even the grade of fever, might put you in different risk categories. Would you like to talk us through some of those?

Alasdair: I think that it's really important because I think actually, when you're managing a children's assessment unit or an emergency department, we spend a whole lot of time looking at different physiological parameters to try and risk assess children. But actually, we know that there are risk categories, the risk associated with them absolutely obliviates any of these other factors, by orders of magnitude, you should be more concerned about children who fall into these categories than any of the children with abnormal heart rates or respiratory rates, because they are at so much more increased risk. So it all essentially comes down to some issue with immunity, either an immature immune system, or a breach in the normal immune system, or actual innate or acquired immune deficiencies. So things like neonates, we know they have very immature immune systems. They are the most dangerous time of your whole life through an invasive infections, within the first few days or weeks. And so we all know you never trust a neonate, that's probably one of the most important groups.
Then there's children who may have breaches to normal immune system, so a central line in situ, for whatever reason, is a breach of the normal protection to your bloodstream from bacteria because there's now a line in from the outside world and so we always have to be cautious with them. And then there are children who have their immune system, their immune cells are not functioning as they should be, either because they were born with a problem with their immune system or they've acquired a disease that suppresses their immune system, particularly some of the oncology patients, or they're on treatments which suppress their immune system. So, the children who have inflammatory diseases, where there are medicines that suppress that it also suppresses the normal function of your immune system. Children who are a long time on long term steroids, these kinds of things. And these are the children that even if they have normal physiological parameters, we should be thinking much, much more carefully.

Emma: Thank you, Alastair, I think it's really important. That brings me down to one of my favourite things to say, it's all in the history. Most of what you'll find is in the history, and your examination is actually only going to back up that history. A good history is what you need. So are you in a high risk population? Are you immune suppressed? Do you have a line? Are you on medication that suppresses you? Have you've got chemotherapy? Have you got an autoimmune problem? Are you a rheumatology patient? I think we so often think about steroids, we often miss children like those with inflammatory bowel disease and don't recognise them as functionally immunosuppressed.

Christo: And I think this brings up another challenge assessing children with autoimmune or inflammatory disease who present with fever, and that's determining what is due to infection because of their impaired immunity, versus what is due to their underlying disease. And whether this is a breakthrough of their arthritis, or if they're about to have a flare of their colitis, for example, I think that's really challenging.

Emma: Which is a really important point because I think we get really focused on infection, but there are multiple causes of fever. What are the other common causes of fever that get overlooked?

Alasdair: What I would say is I don't think there are any other common causes of fever. There are there are other causes of fever there, but they're all relatively uncommon and obviously because they're not related to infection they are less interesting, sorry, to all of the non-infection specialists out there, but that is the truth! They are most commonly probably inflammatory conditions, so auto inflammatory conditions. And I guess the one that paediatricians think most about would be Kawasaki disease, that we are hopefully thinking about in any child who have a fever or five days or more duration. But then there are other kind of rheumatological diseases that can present with fevers, and obviously one of the other ones with a persistent fever not to miss is malignancy. And this can very often be one of the presenting features of that. So I think those are the big three to think of. So, it’s infection, infection, infection, infection, and then also autoinflammatory and haematological malignancies. Those are the big three.

Emma: While we're talking about the causes of fever, the other thing that I think people get really hung up on is how long the fever lasts. So apart from coming in and saying my child was better 40, lots of people come into me and say the fever still there after five days.

Alasdair: I think there's probably two reasons for that. So one is the all of the bottles of paracetamol and ibuprofen liquid say on them don't give for more than three days. And so after three days of giving their children paracetamol and ibuprofen, parents think that they need to see a doctor no matter how well their child is, which is obviously not true.
And then the other thing is, this magic five day cut off that paediatricians try and drill home. And that's purely because that's the point at which we want to make sure that the child has an infection and doesn't have something like Kawasaki disease, and we want to roll that out. And that's because we know that early treatment really improves the prognosis of that condition, so we want to catch it early.

I think what's really worth bearing in mind however, is that there's not really a well characterised normal duration of fever for sort of benign childhood viral infections. You know, a lot of them will resolve in two to three days, but we see plenty of normal coughs and colds where the fever will go on for five, seven days, sometimes even longer. And we do end up investigating these children once it's gone on for quite a prolonged period of time, but often for children with a very clear source, who are well as long, as you're providing good safety netting advice, even a fever of a duration of five to seven days doesn't necessarily need anything special being done. Because we know that this is just normal or, you know, a non-insignificant portion of children with these illnesses.

Emma: I couldn't agree more. I think things like RSV (respiratory syncytial virus) and influenza, they really drag on and people forget, and they think why this like a normal cold is so they tend to worry. The only time that I really worry is when a child's got better and then worse again, so the classic time is catching chickenpox, having a bit of a fever, fever goes away, child gets better, child then develops a second fever and I do worry about those secondary bacterial infections after a serious viral infection. So classically, chickenpox, occasionally flu, and we've seen it with COVID.

Alasdair: Yeah, that's a really good point, and it's one of the things I've started saying more often, in the past few months, actually, to parents as part of my safety netting advice because we do see quite a lot of these reattendances when the clinical picture hasn't changed. And so what I'm trying to reassure parents more these days is, within a period of a few days, if child hasn't improved much, that's not necessarily a concern. We know that it does take a while for kids to get better from these, so staying the same is not so bad. Deterioration is when we become concerned, so if they're getting worse, that's a much better sign that you should be bringing your child back to be reviewed again. But staying the same for a while can be just normal.

Emma: It’s the one question I always ask parents, I often ask parents, what is it about this illness that is different to previous illnesses that made you come? Or in what way has your child changed or differed?

Christo: At this point is probably worth highlighting, and I think it's something that we could all do with communicating to parents and families that we see presenting with a child with a viral illness, that there is a normal number of viral illnesses that your average child under five might have in a year.
And this might vary, but the number of normal episodes can be quite high. And I think there's often a mismatch between what we see as a normal number of illnesses in a given winter or in a given year, and what parents feel should be normal.

Emma: I always tell parents that you can have 10 to 12 viral illnesses a year. Now say, you don't get one or two in the summer, that's absolutely one a month or more, so you'll be ill for two weeks, well for a week and then you're on to your second one. In real terms, if you've ever had a child that's snotty the whole entire winter with intermittent fevers, and that's normal and that's important. And that's part of maturing your immune system. So it's a good thing, not a bad thing.

Alasdair: Yeah, and I guess that's one of the things that we often see these children who get brought in and they don't look very unwell and the parents will say, you know, he’s not that sick, but he's been ill so many times there's got to be something else ging on, this is like the fourth cough. And then this is the conversation that sometimes take a little bit longer, to just try and break down the fact that, particularly really young preschool aged children, this is unfortunately par for the course, particularly if they're in nursery or preschool, or they've got an older sibling in nursery or preschool or, in the early years of school. This is where all of these bugs come home and where they get encountered for the first time. And so your body is just learning how to recognise them and respond to them, and unfortunately, that means feeling a bit poorly, for pretty much a whole winter for a while.

Emma: But actually there's a positive side to that, because if you meet these viral infections when you're young, so take the example of EBV Epstein-Barr virus, it will be a minor viral illness you’ll never notice. If you live in a nice, middle class, very clean house, don't socialise with other children and you only meet EBV you're a teenager you're in for a much more serious, prolonged illness. So I do say to parents, although they're ill, actually this is what you want. This is part of building up your immunity and meeting viral illnesses at a young age is important, and it's positive.

Alasdair: I guess the sad truth of life is that there's a very large number of viruses for which infection is ubiquitous, there's no avoiding it. Almost everyone is going to encounter it, at some point. And for a lot of those, your body is really designed to encounter them for the first time in those early years.
That's what we're adapted to, because that is the normal experience, that is when you're normally coming to terms with them for the first time so your immune system is geared up for that. And that does mean that a lot of them, you will experience a much more minor course in that very early period of life rather than later on. The really classic example is chicken pox that we all know, get it when you're really young, generally pretty mild and as a you know, a teenager or adult it's pretty, pretty horrendous. It's just the way we've adapted to be sadly!

Emma: Well controversially, we could be like America and Australia and vaccinate for chickenpox, but I don't want to stir up more controversy in this podcast.

Alasdair: We should definitely vaccinate for chickenpox, I'll just put it out there. We should just get on and do it.

Emma: So, we've talked about what fever it is. We've talked about what's normal. We've talked about high fevers not being a problem. We've talked about the length of fevers and having lots of infections over a winter as also being normal. But what about pyrexia of unknown origin (PUO)? At what point can they call something a PUO?

Alasdair: It's two weeks Emma, as I'm sure we all know, it’s two weeks obviously.
What I guess important is to remember, I'm not very pedantic about a lot of things but PUO is one of the things I am a little bit pedantic about, because when we see children who have been febrile for a few days, who present and there's no clear source of the fever, they will often be labelled as a PUO. But it's not a PUO, that has quite a specific meaning in medical terminology, and it refers to a prolonged fever, longer than two weeks of duration that has no clear source. And it's important, because for normal children coming into primary care with a brief history of fever, with no clear source, it will almost always be infectious in origin, over 99% the time. For a PUO, and that prolonged duration of fever with no clear source, actually infection is still on the list, but you need to really be thinking about other conditions because it's very unusual for an infectious fever to last that long. And so that's when it does prompt, much more detailed investigation, and you really need to be confident of the source of that fever before you can move on and do anything else.

Christo: And it's probably worth highlighting that true PUO Isn't that common. Certainly, in comparison to the number of children, like you described, that have a fever without an obvious source for three or four days. These aren't patients that you should be seeing every day, or even necessarily every week, depending on how big your catchment areas.

Emma: I'm just saying that PUO is a child with a fever and no upper respiratory tract symptoms, o not a cough and a fever, not a snotty nose and a fever. It's just that the fever.
I think this brings us along to a really interesting question because you said to us, if you have a prolonged fever you need some investigation. Now I read that is if you have a normal fever, you do not need much investigation. What do you have to say about that?

Alasdair: I'd say I'd largely agree with that. I have my own sort of internal framework for managing fever, because it's by far and away the most common thing we see in paediatric acute paediatrics. It's really useful to have that kind of framework so you can very quickly move through your assessments and do it in a consistent way.
So, obviously, the first question with any child with a fever is do they need resuscitation? Most of the time? It's no. So that's an easy point to move past. And then the next question is, is there a clear source? If there's a clear source then you very rarely need any investigation because you just manage the source as it needs managing and most of the time, that is no treatment. Then for a small proportion of the time that will may be bacterial infection like pneumonia or a urinary tract infection, and the overwhelming majority of those can be managed with oral antibiotics. And sometimes you may want to use IV antibiotics for children who are very severely ill.
And then if there's no source, the next question is, are there any red flags? So, we will see actually quite a lot of children who have a brief history of fever with no clear source, and then you're going to be looking for things in the history or on your examination that are signals that this is more than a benign childhood viral infection. So that's things like the child appearing more unwell than they should, not responding, being lethargic or floppy, very poor urine output or fluid intake and these kinds of things. And if there's red flags, that's the time at which you need to do investigation, because now you're wondering, is there something more than a normal, benign childhood virus here that would need a treatment? And the question that's really on our mind is, could this be an invasive infection like a bacteraemia? That's the question you really want to answer with your investigations.

Emma: The problem about the red flags is we know that if you look at the nice red flags, I think they did a nice study in Liverpool and they showed when they looked at 20 and 30,000 children that half have red flags, straight off. You're in a really difficult position because half that’s fine, you can send them home, you've still got half children with a fever, but we know that about 10% of the children are likely to have serious bacterial infections when they present to the emergency department and the red flags have only chopped that in half. Now we don’t want to investigate too many and I think the bit that everybody struggles in is who gets blood test, and which blood tests do you do on these children who probably have viral infections.

Alasdair: Everyone does struggle with that, you're right. What I would say is that there's a difficult trade off here between expediency and invasiveness of your management, I think. So one of the famous paediatric sayings is ‘the observation is the best investigation’. And quite often these red flags, like abnormal physiological parameters or the child behaving unusually, it can just be due to having a fever at the time. And once you've given them a little while to have an antipyretic and to drink an hour or two later, they'll look completely different. And anyone who's worked in acute paediatrics will know, you can go from having a child who you're wondering if you should move them round to Resus, to jumping on the bed eating, a packet of crisps and singing, within the space of like an hour or two, just because the fever resolves. So I always think if you're not sure, if the child is stable, it is fine to just wait a little while because if you do blood tests and you weren't sure if you should do blood tests, you will quite often end up being unhappy that you did a blood test. Because your inflammatory
markers may well be in a zone where they don't rule anything out and they don't make anything likely enough to really make you feel compelled to act. And that is a really difficult position, I'm sure we've all been in more than once.

Emma: I couldn't agree more. And I think you need to remember the new sepsis international consensus guidelines say that you only need to do investigations and treat within an hour if you're shocked, and very few children we see are shocked, most of them are febrile. And in those febrile children you've got three hours, so that is long enough to give them paracetamol, ibuprofen, and a drink, and wait because watchful waiting, as my grandmother and you say, is the most invaluable thing, or masterly inactivity.

Christo: I think you've mentioned there Alasdair about the amazing recovery some children can make with just some antipyretics. Are there any downsides to treating fever in an otherwise relatively well child has no risk factors and most probably has a viral upper respiratory tract infection?

Emma: Okay, so Alasdair I'm a bit hardline about this, because I think that having a fever is a good thing. I mean, it's the body's way of trying to get rid of viruses. So, I tell parents they should only give their children paracetamol and ibuprofen if they look miserable, or they're clearly in pain. They do not need to keep giving paracetamol and ibuprofen just because they have a temperature, if they're running around and looking fine. What's your view on this?

Alasdair: I'm sure it will come as no surprise to you Emma that I completely agree. I think you're completely right. And I guess the reason is to understand what why are we treating fevers? The reason is not because the fever is a danger to the child, so having a high temperature poses no risk for the childhood at all. It's a function of your body trying to help you clear the infection. So why do we treat it? Well, we treat it because actually, as one of the side effects of a fever, you feel dreadful, quite often you feel terrible. And actually, this is another adaptive mechanism of fevers, you're supposed to feel terrible so you go and lie down and you don't go and infect your tribe members or your members of your household or whatever. So it's supposed to make you antisocial. But we don't we don't like children feeling awful, and so we know that there's something quite effective we can do to try and help them feel better, so we can give them medicines like paracetamol, ibuprofen, which are quite effective at switching off that internal mechanism driving the high temperature and can make you feel more comfortable.

Emma: Now, interestingly, we use paracetamol and ibuprofen a lot in this country. But my German friends think we're absolutely crazy because they never use ibuprofen in Germany and they think it's a very, very dangerous drug.
So are there contraindications for using ibuprofen?

Alasdair: If you have certain platelet problems or clotting abnormalities, you might be told to avoid ibuprofen or similarly, children who have a history of gastric ulceration or very severe gastroesophageal reflux disease might I'd avoid it.
But the one that gets talked about probably the most is chickenpox as a reason to avoid ibuprofen, this is somewhat controversial I must say. The recommendation is based on some quite old observational evidence that found children with chickenpox who went on to develop necrotizing fasciitis, a flesh-eating bacterial disease, as an adverse effect of the chicken pox, they were more likely to have been given ibuprofen earlier in their illness than children with chickenpox who didn't get necrotizing fasciitis. Now, what’s not clear is whether children who got necrotizing fasciitis looked more sick, and so were more likely to have been given ibuprofen rather than being given ibuprofen made them more likely to get necrotizing fasciitis. So, it's what is the cause and effect of that association? It isn't clear. And so because there is an alternative to ibuprofen that isn't associated with this risk, the advice has just been to avoid ibuprofen because there's a safe alternative, so why do you need it?
In practice, we, as healthcare providers will sometimes see children who have chickenpox whose symptoms are not well controlled with paracetamol. And I think it's perfectly acceptable to give children ibuprofen in that setting to try and relieve their symptoms because if there is an increased risk, the absolute risk is really, really small. Very, very, very, very small. And I think most people would agree, it’s easily outweighed by the symptomatic benefit of giving a briefing to children whose symptoms wouldn't otherwise be well controlled.

Emma: Great, so paracetamol is absolutely everybody. Ibuprofen cautiously in anybody with clotting disorders, gastric problems, asthma occasionally, chicken box give it with caution.

Christo: What causes fever in a physiological sense?

Alasdair: So a fever is a normal physiological reaction to an infection. So, this is something that's conserved across all sorts of animal species. So even cold-blooded animals will go and lie in the sun to make themselves hotter than they would normally be, to try and drive their body temperature up when they sense an infection. So you see this across all hosts of animals. And it's triggered by chemicals that are called pyrogens, and these can either be endogenous, the chemicals you make yourself like cytokines, and things that you would make in response to your body noticing an invader, or sometimes elements of the infection themselves can be pyrogens, things like the lipopolysaccharides membrane on the outside of Gram-negative bacteria. And when your body recognises these chemicals, your hypothalamus sets a new higher target temperature. So, the part of your brain that controls normality says right, we need normal to be higher. And so, your body then sets about doing all the normal things that would do to try and make you warmer, so it makes your hair stand on end, it sends blood away from your fingers and toes and into your core, it makes you feel cold so you go and do things to warm yourself up, by putting on a blanket and going somewhere warm. And the reason it happens is actually not that obvious. It's not very well defined, precisely the effect that fever has that's beneficial, but it appears to slow down the growth of viruses and bacteria, so it helps stop them going so quickly. And it also seems to activate different parts of your immune system to help them respond.
So, I always say to parents, fever is something your body is doing to the infection, not something an infection is doing to your body. So, it's the body's way of trying to help and the reason why that's useful to know, is it takes some of that fear away because people are often very scared that their child is going to come to harm as a result of the high temperature. And once you let people know that your body is in control, it's doing it to benefit you, it's something healthy that's happening, that can help take the edge away of some of that fear that the child is going to come to harm because their temperature is too high.

Emma: I think that is the crux of this whole podcast. That fever makes parents scared, they fear fever. Fever is part of the normal adaptive response, and we should all embrace fevers and recognise that it is normal.

Alasdair: Absolutely, sign of a well functioning immune system.

Emma: And the flip side to that is that parents need to recognise deterioration in their child and know what a sick child looks like. And that's not just a fever, that's a whole host of things.

Christo: To follow on from that, Emma. It's also worth pointing out to parents that sometimes absence of fever doesn't mean that there is no risk. So, thinking particularly about neonates and immunosuppressed patients who might be normothermic or even hypothermic in response to even significant invasive infection, or patients who are on immunosuppression, who might have the same inflammatory response. And it's sometimes easy to give the wrong message that not all fevers are bad, but absence of fever is a good thing. Whereas if your child looks unwell and you're worried and you think they're deteriorating, then not being febrile shouldn't be a reason to not seek advice.

Alasdair: One of the things that I say to parents as part of my home fever spiel is that the fever itself is not really of interest to us as doctors so that a fever is just one of the many symptoms of an infection. So, when we know that you have a fever, we just know there is likely an infection somewhere. The fever then is not that interesting. What we want to know is what is the infection and is it an infection that can be treated or that poses a serious risk to the child. But although so much attention goes on fevers, and actually the relevance of a fever is not that much once it's told you there's an infection present, it is the infection that needs the attention.
What I try to do is the best summation of you, what is normal sick, what is sick sick? I as parents try and remember the last time you had like a nasty flu like illness, and remember how you felt and how you behaved, and you just wanted to go to bed and sleep all day, you weren't interested in foods, you might drink a little bit, but if someone came to try and wake you up, it wouldn't be difficult to wake you up. And you know, you were still able to force a little bit of food and drink down if you knew you had to, and you didn't have any of difficulty breathing or those kinds of things. And that's I hope is a useful shortcut for parents to try and think well, if my child is sick, they're going to look like that, because they're sick so they'll look like sick. But what is sick enough, or you know what is out of the ordinary and needs additional medical attention? So trying to put that in a in a frame of reference from their own experiences I hope it's helpful.

Emma: I think that's what we call the Mars bar or £20 note tests. So you say, Would you like a Mars bar? Would you go and pick up a Mars bar? Would you pick up that £20 note? If you're so sick that you wouldn't go pick up the £20 note, or if the child says, ‘no, I don't even want to Mars bar’ that's when I worry.

Christo: Alasdair, do you think this frame of reference that we're talking about has changed at all over the past three years? And we ask this in January 2023, after three years almost living with COVID and it going from pandemic to endemic, and the recent fear about group A strep. Do you think our frame of reference and parents frame of reference about what normal is for infections has changed?

Alasdair: I think that's a really good question. And I think I don't really get a good sense to be honest as to how it's changed at a population level. I think it's very different for individuals. So certainly, it's been a very traumatic few years for a lot of people and I think health anxiety will be a real problem for some families, certainly. And understandably so. I think, perhaps, for want of a better word, the normalisation of COVID and the discussion around the symptoms you could have with it, people are coming to terms with the fact that it is now a normal part of life and to expect that people will catch that infection and they will have these symptoms and then they will go away and that's okay. Maybe for some people this may help normalise viral or respiratory infections as a sort of a fact of life. So I think, it could sort of go one of two ways for different people as for how that's averaged out, and how many people may have been pushed one way or the other? I'm not sure.

Emma: I think your point about health anxiety is really important. I think people are worried and anxious. And I think that's on the backgrounds of during lockdown, children didn't see other children. They didn't go to school, and they didn't get any infections, so for a year they appeared well, and then of course when they finally got back to school, they got all the infections they missed, and they seem to be a bit more unwell and that was a nasty shock to everybody.
One of my take homes is that people forgot what viral infections look like. The other is, everybody washed their hands in COVID and infections went down. And I'm just saying hand washing is a very good thing, probably more important than all those antibiotics unnecessarily get!

Alasdair: Washing is very, very underrated, very underrated. We're going to make hand washing great again. Make hand washing great again! That's my new motto. You'll see it on my hats I'll be wearing in the future.

Emma: At the end, we always give everybody the chance to give us their three top tips. What are yours?

Alasdair: Number one, a fever without a source doesn't need investigation if the child is otherwise well, and there's no red flag signs.
Number two, fever is a normal physiological response to an infection. And that if you're able to explain that to parents, you will change their whole perception of febrile illnesses in their child going forwards. So, it's a really worthwhile investment on that first encounter.
And I think my third one is that observation is really a wonderful investigation for febrile children because it is normal for children to look quite dreadful whilst they're febrile. And if you're concerned, sometimes just a little bit of time, allowing that fever to come down and the child can honestly look like a completely different child and save you the hassle of the investigations and all those other things.
So, I think those are my top three.

Emma: I’m just going to take you to task with number one. So the child that looks well has a fever, do they need a urine culture? Or not?

Alasdair: Most of the time, they don't in my opinion. though, there will be some, any child under three months, I would always do it. Under six months with no clear source is probably wise. And then from that point onwards you can sort of risk stratify based on how long they've been febrile, and also if it's a boy or a girl. So, older boys sort of over the age of two with no history of urine infection, the likelihood of picking up a first UTI it gets progressively lower and lower and lower, especially without any urinary symptoms. So, think twice before, reflexively requesting that urine sample that is going to come back contaminated.

Emma: Now we're in complete agreement. And in my books, anybody who's got a runny nose does not get a urine sample because it’s the runny nose causing the fever.

Christo: There's also something about the way in which you collect your urine sample. The common approach of sticking a piece of cotton wool in a nappy to fester for four hours, and then our surprise when it grows, staph epi or some other skin commensals, that really needs to stop.

Alasdair: I think I'm going to try really hard not to go off on a rant here. But please, please don't ever put a urine bag on a child. That's all I'll say about it. And I'll just draw a line under it there. Never put a urine bag on a child. That's the end.

Emma: I wanted to say, clean catch only.

Alasdair: Or catheter in a little baby. You could do a catheter, some people would still do SPAs (suprapubic aspiration). Wild people, I'm not sure why they're still doing that.

Emma: So, SPAs, suprapubic aspirations, were a great thing when I was a junior doctor. I actually loved it because you could do your sepsis screen super quick because you do blood, Lp (lipoprotein) quickly, stab the bladder with a clean needle, an aspirate. Now obviously this was A) very invasive and B) a number of my friends got gastric contents, and you did wonder about the safety of this.
Fortunately, those days have passed, SPAs are dead to us now, unless you have ultrasound guidance and a very good reason to do it.

Christo: I think particularly in the face of things like the patented quick wee methods. I don’t know if you’re familiar with this. There was a great paper that was in archives a few years ago looking at basically if you get some cold water on some cotton wool and rub the tummy, it's likely to encourage urination in a very high proportion of infants, so great for those sceptic work ups.

Alasdair: Just speaking from my own experience, I did do it a few times and the looks the parents gave me put me off doing it again! I’ve only done a couple of quick wees as the parents stared on at me in complete disbelief. Here's the weird doctor, just got to get the wet cotton wool, stroking their child's lower abdomen with it!

Emma: I think it's been a great pleasure to talk to you Alasdair. It’s been really fun. I love your top tips. I think that you have really reassured us, and I think that listening to this, having these facts at your fingertips means that we can reassure parents that in the majority of cases fever is not something to fear.

Alasdair: Thank you so much for having me.

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This podcast is a collaboration between Medisense, medical education and the Royal College of Paediatrics and Child Health. You can find more creative learning resources on www.medisense.org.uk and of course a wealth of information on the important work of RCPCH on www.rcpch.ac.uk or #ChoosePaediatrics.

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Emma: The views, thoughts and opinions expressed in this podcast relates only to the speaker and not necessarily to their employer, organisation, the Royal College of Paediatrics and Child Health, or any other group or individual.