Zero to GP - GP Revision Podcast

Infectious Mononucleosis (Glandular Fever) - Essential GP Revision

• Thomas Watchman • Season 1 • Episode 16

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0:00 | 13:20
SPEAKER_00

Hi, this is Tom from Zero2GP. In this episode, I'm going to be going through infectious mononucleosis. And as always, the format is I'll ask questions. You take some time to think of your answer. Ideally write it down, and then I'll go through the explanation. If you're preparing for your AKT exam, I highly recommend checking out the AKT Revision Book at Zero2finalsShop.com, the zero to gp.com website, which is a full question bank and everything you need for the uh AKT exam. And I've got an upcoming AKT revision course in London on the 13th of September 2026, which is a full day long teaching session with me, and we cover everything you need for the AKT exam. But for now, let's get straight into this episode. So our case is an 18-year-old man who presents to his GP practice, and he's got a five-day history of a sore throat and a low grade fever. So he comes in, oh got a really sore throat. You have a feel of his neck and his glands are all swollen. He's got bilateral and posterior lymph adenopathy. And then you have a look in his throat, or you don't, someone else does, and they see this. So this shows what we call a whitewash exudate across quite swollen tonsils. And what happens? He's prescribed amoxicillin. Why they didn't go for the typical choice of phenoxymethyl penicillin or pen V, we're not sure, but he's been prescribed amoxicillin. So the first question I have for you, because you know the answer, you know this is suspected mononucleosis. My question for you is what happens when he goes away and takes this amoxicillin? So the answer is he develops an intensely itchy maculopapular rash. And this is a typical thing that you see all the time in exams. Uh, I've seen it in clinical practice, but um it's very common in exams, so they develop a rash. So here we have this the a picture of what this rat this rash that appears on this 18-year-old man who's uh presenting with these symptoms. So let's just summarize. We've got this 18-year-old man, and then he represents, and now he's seeing you, and he's got this itchy macular papula rash. He's still symptomatic, so he's still got some sore throat, some low grade fever, uh, some lymph adenopathy. Now he's on day nine of the illness, and you're suspecting infectious mononucleosis because you read the title of the video. So the next question is what's the first line test in the nice clinical knowledge summaries for infectious mononucleosis or tests? So in the NICE clinical knowledge summaries, they say the first line test is you should do a full blood count with a differential white cell count, so blood film, and heterophile antibody test or a monospot test. And this is uh you you can only really do this in the second week of illness and onwards, because if you do it too early, um, there won't be enough time for the antibodies to develop so that you get a positive reaction on the test. So let's take a moment just to talk about the heterophile antibody or monospot test. How does this test work? Well, we give the lab a sample of the patient's blood and they mix that blood with animal red blood cells. And the antibodies in the patient's blood, which are created in response to the Epstein Barr virus or the infectious mononucleosis, those antibodies react with the animal red blood cells. They're heterophile antibodies, so they they kind of cross-react not only with the virus, but also with animal red blood cells. So you get a reaction when you mix the two. The monospot test uses horse red blood cells, and the pull bunnel test uses sheep red blood cells. In the first week of illness, there won't be enough antibodies developed, there won't be enough heterophile antibodies in response to the virus, so the test can be negative in the first week of illness. So usually you do the test from the second week onwards. If the test is negative, the advice is to repeat the test in five to seven days if you're still still suspecting infectious mononucleosis. So my next question to you is what would be the finding on the white cell count? So you do this differential white cell count. What finding do you expect in infectious mononucleosis? The answer is raised lymphocytes specifically, and those lymphocytes are atypical or reactive when they're looked at under the microscope. And this is typical for Epstein-bar virus infection. The next question I have is what's the alternative test? Let's say for some reason you can't do the monospot test or the heterophile antibody test, or that test is negative. What's the alternative test for infectious mononucleosis? The answer is to test directly for Epstein-bar virus antibodies. And in some areas, I know for me, um, the lab that that uh where I work doesn't really do the heterophile antibody test. They just tell you to get the Epstein-bar virus antibody test. So you might find in clinical practice, although the the nice clinical knowledge summaries say do the heterophile antibody test, you might find in reality they the lab just tells you do Epstein bar virus antibodies instead. So this is actually the first line test, DBV antibodies, is the first line test if they're aged under four or if they're immunocompromised. The other time you might use it is if the monospot test is negative and you still need a diagnosis, particularly if you need a more urgent diagnosis. For example, there's somebody who does contact sports and they need to know whether it's safe for them to go back to playing rugby or some other contact sport. So the next question I have what is the interpretation of the results of the eps uh of the EBV antibody test? So when you do the EBV antibody test, you're gonna get back two results. The first is IgM, EBV antibodies, and IgM, the IgM version, rises early, and this suggests acute infection. So if the IgM is positive, it's probably an acute infection with EBV. I remember M from miserable because they're symptomatic and they've got the infection. IgG, but the IgG version of EBV antibodies persists after an infection and it shows immunity. So you can remember G for gone or G for got it already. And this this, if you get positive IgG and negative IgM, they probably had EBV infection or they they probably had infectious mononucleosis at some point in the past, but they're no longer, it's not an acute infection, it suggests immunity. So if someone's symptomatic and they've got IgG positive, IgM negative, it's probably not the infection, there's it's not an infection causing the symptoms. Okay, so we've got this 18-year-old man, he's got a sore throat and low grade fever, and he's got a positive monospot test. So we can say, yes, you've got glandular fever, that's probably why you're feeling unwell. So the next question is you do some other blood tests, what other abnormal blood results might you find in infectious mononucleosis? Infection can cause slight hepatitis, so you might get raised liver enzymes like raised ALT or raised AST. You can also get a rise in bilirubin from some inflammation in the liver, but also from hemolytic anemia, which we'll talk about. On the full blood count, you might see a mild thrombocytopenia, so a slightly low platelet count. And in some patients, it can cause hemolytic anemia, although this is a bit more rare. So you might find some anemia because the red blood cells are being destroyed. Next, what would you check on examination in this patient? What's a key thing to check when you're examining the patient? A key important finding is splenomegaly, so an enlarged spleen. And this is really important because if the spleen is enlarged, there's a risk of splenic rupture, so the spleen actually rupturing. So feel whether there's a large spleen. My next question is this patient's confirmed with the diagnosis. What how are you going to manage them? What's the treatment for this?

SPEAKER_01

The treatment is really supportive.

SPEAKER_00

There's no specific uh drug that you can give that will treat the condition, you just wait for the infection to clear itself. And so they need rest, fluids, and analgesia like paracetamol or ibuprofen, just to help with symptoms and they will recover from it on their own. Although they can have lasting fatigue after the illness. The next question is: how is Epstein Barr virus that causes infectious mononucleosis, how is it transmitted?

SPEAKER_01

It's transmitted through saliva.

SPEAKER_00

So obviously, you don't want them going spreading the condition. Um, so you would give them some advice about uh avoiding transmitting it to other people. So avoiding things like kissing. It's known as kissing disease because it's spread through saliva when you're kissing somebody. Um avoid sharing you tensels, toothbrushes, things like that that might spread the saliva. Although they don't need to, uh and then obviously hand hygiene and things like that. Although they don't need any time off work or school if they're um you know they're not too symptomatic and they feel well well enough to go in. And finally, what activities would you advise this patient to avoid um given that he's got infectious mononucleosis? The two key things to avoid the first is excessive alcohol consumption as it can affect the function of the liver, and uh uh the alcohol plus the hepatitis from the uh infection is going to irritate the liver more. The other thing is to avoid heavy lifting and things like contact sports, because this can cause uh a ri uh the this increases the risk of splenic rupture. If they've got an enlarged spleen from the condition, you don't want to have somebody get tackled on a rugby pitch and that's spleen to rupture. Generally, if it's been more than three weeks since the onset of the illness and they're feeling completely back to normal and well again, then they can return to normal activities. So I hope that episode was helpful. Um, and I'll see you in the next episode.