Therapeutic Guidelines Sore Throat

Investigations are somewhat limited by the turnaround time of these tests, as well as whether the result is going to have a meaningful impact on your management of the patient. Just because you detect Strep pyogenes doesn't necessarily mean it's a causative pathogen.

[Music] Welcome to the Australian Prescriber podcast. Australian Prescriber, independent, peer-reviewed and free.

Hi, and welcome to this Australian Prescriber podcast. I'm Dr Justin Coleman, a GP in Brisbane who also works in the Northern Territory. And we're here today to talk about sore throats. One of the most common presenting issues in general practice throughout Australia and no doubt throughout the world. With me, I have Dr Emily Tucker. Welcome Emily.

Hi, thanks for having me.

And Emily, you're an infectious diseases physician at Flinders Medical Centre in Adelaide and you did the literature review and then were on the expert panel for the sore throat section of the TG Antibiotic guidelines, which has just been updated. And I gather the sections now sometimes get updated one at a time, is that right?

They do. If there's been key publications in the intervening period between the major updates, then we do targeted updates. And so subsequent to the last Therapeutic Guidelines, the 2020 Australian Guidelines for Prevention and Management of Acute Rheumatic Fever and Rheumatic Heart Disease were published. And so, this triggered this update.

Wonderful. I actually love talking about things that are common and subtle, and I think sore throats do fall into that category. I was pleased to see a nice algorithm for assessing and managing an acute sore throat at the start of the chapter, which gives you a simple yes or no answer when you flow through that diagram. And I guess near the top of the algorithm is the assessment as to whether the person needs hospitalisation. What sort of things would make us want to send someone to a hospital?

You need to look for some of their key clinical features that are suggestive of a potential complex issue that’s sort of outside the scope of primary care, like airway obstruction or a deep neck space infection. There's a table which highlights some of the key clinical features that could be suggestive of this, which would alert a clinician to refer somebody to hospital, like a presence of drooling, neck swelling, severe neck pain etc. And then it goes on to give you some conditions which can cause more significant issues that require hospital management. But I agree there's a lot of complexity to what we consider to be a little bit more simple, which is the management of a sore throat in the primary care setting.

Take us now through the causes of sore throat and perhaps it's a bit like location, location, location for real estate. It really is virus, virus, virus, before you get to anything much else for the average winter sore throat.

The most common cause of sore throat is viral pharyngitis [or] tonsillitis. It's an infectious cause. And obviously most of these patients do not have bacterial infection that present with sore throat and do not require antibiotic therapy. So, it's really key to recognise that.

And then when you do get onto the bacteria, so the good old Strep pyogenes which has been around for tens of thousands of years in human beings, still remains the major culprit.

Exactly. Yeah. So, group A strep or Strep pyogenes is the most frequently implicated bacterial pathogen as a cause for sore throat. But in most people still, this is a self-limiting condition that does not require antibiotic therapy, but selected patients do require antibiotics for treatment of group A strep sore throat.

Just thinking of other causes, GPs are always thinking of something like Epstein-Barr virus, which of course can be confused because of the pus on the tonsils. And then you've got the things which, once you've seen them a few times, they're probably a bit easier to recognise and diagnose. So hand, foot and mouth, and herpes dermatitis. And then I guess there's a handful of rarer causes like gonococcal. Anything else we should be thinking of there?

It’s probably useful to emphasise that there is quite a nice table of differential diagnoses for sore throat in the Therapeutic Guidelines in this edition that's had a few updates. And when you're considering differentials, like for example herpetic lesions, if you are looking to test, you need to request different tests and occasionally a patient can present and this can be missed. So it's important to think about other aetiology, particularly if the patient has particularly suspicious lesions etc. And in sexually active patients to think about sexually transmitted infections as well. But then as you go down, you're getting to some much rarer causes. It's also important to consider non-infective aetiology.

What sort of things are we thinking of there?

Reflux disease in the correct patient population, postnasal drip in patients with allergic rhinitis, dust mite allergy, cigarette smoke, malignancy, some medications, trauma etc. will be some of the non-infective causes to think about.

And of course, we've covered this under viral, but never let a podcast in 2022 go by without mentioning coronavirus. COVID-19 of course can cause a sore throat.

Yes, exactly. And when you're starting to think about diagnostic testing, obviously the guidelines continue to change for the management of COVID and how we should test what, so you need to refer to your local public health guidelines for testing.

One thing I've always been interested in since I first started medicine is trying to distinguish between viral and streptococcal pharyngitis. And I remember a wise old GP telling me once that the more the runny nose is, the less likely it is to be bacterial, although frequently patients have the exact opposite impressions. So they'll come in and say their snotty nose has gone green and also to be fair, some doctors and in the past pharmaceutical companies, I think also had messages that if anything goes green, it's time for your antibiotics. So, I guess a laryngitis where you lose your voice and lots of rhinorrhoea are hallmarks of things being likely to be viral rather than bacterial. What else is there?

It’s not always very easy to discern between viral and bacterial aetiology for sore throat. And I think a lot of people have had a go at different scoring algorithms and different ways of trying to work it out clinically and to date, none of them have been particularly successful, but if the patient does have classic features of a viral infection and you've listed some of them, but nasal congestion, a clear viral exanthem, conjunctivitis, diarrhoea, those sorts of things, then obviously it's going to push you much more likely down the pathway of a viral aetiology. Some of the suggestions that this could be a bacterial infection is potentially an abrupt-onset high-grade fever, cervical lymphadenopathy, presence of an exudate, but as you pointed out previously, that's not always that helpful. And then the absence of these viral-type symptoms.

And I should briefly touch on scarlet fever, which seems to hail straight from a Charles Dickens novel. And we see it less often these days, but it still is around. And I take it's more important to treat the strep that causes scarlet fever, is that right?

As with anything in this area, I think we’re always lacking a perfect evidence base to tell us exactly what to do. And there are some differences in guidelines around the treatment of scarlet fever. The recommendations around treating scarlet fever, and it is recommended to be treated with antibiotics in the Therapeutic Guidelines, are really twofold. One, because of the severity of the infection and the other is really to prevent onward transmission of this more severe toxin-producing strep.

Now, given we're often not entirely sure whether it's viral or bacterial and I think on first principles, we should assume more of it is viral than bacterial, is there a role for investigations to try to sort out the two?

In primary care, the investigations are somewhat limited by the turnaround time of these tests, as well as whether the result is going to have a meaningful impact on your management of the patient. Just because you detect Strep pyogenes doesn't mean you necessarily have to treat it. And a certain proportion of the population, maybe 10% or so of children, will be colonised with group A strep in their throat. So just detecting it doesn't necessarily mean it's a causative pathogen either.

It's not recommended outside of a few indications to actually take a swab for culture. For the patients at the highest risk of developing acute rheumatic fever, it's recommended. But particularly in those settings where you may not have ready access to a microbiology lab, it's pretty hard for that test to give much impact on your clinical decision making.

Yeah, I certainly read some American-based articles where people are adamant that everyone should get this rapid antigen testing or-

Yeah.

... similar on-the-spot testing. Although I do also read some very sensible public health people in America saying that really they're not convinced it's particularly useful and it costs a lot of money and gives it false confidence in many cases.

Yeah, you're right. And I think this is where it gets confusing for anyone that wants to look up guidelines. A lot of people rely on tools like UpToDate, which obviously’s got an American slant to it. And the Americans really do focus their guidelines on treatment – so treatment based on the detection of group A strep. And they rely quite heavily on rapid antigen testing for group A strep. There are also potentially some rapid PCR tests that may become available in the future, but these tests aren't readily available in Australia. If you could have that result in front of you with a patient, it potentially would be helpful, but how that actually impacts on antibiotic prescribing and potentially antibiotic over-prescribing and the issues with the sensitivity of the test means that it's not something that we're incorporating in our decision-making algorithm at the moment.

Yeah. I think that's a very sensible approach from TG really erring on the side of ‘wait until someone produces positive evidence.’ And the evidence can't just be that, ‘Oh, this test detects something quite well.’ The evidence has to be, if the population is using this test in a widespread manner, are they better off than if they're not? And I think that hasn't been shown to be the case.

Yeah. And interesting, if you look at other evidence-based guidelines from the UK and other sites say they recommend against testing at all, you are seeing some quite disparate guidance in this area, but yeah, certainly the American approach is based around rapid antigen testing, which now in the Australian context, we're getting a bit more experience in the utility in the context of COVID.

Just before we move on to treatment, I did want to touch on something that certainly I've seen a lot of. I live in Brisbane now, but I have spent my previous three years on the Tiwi Islands in a remote Aboriginal population and acute rheumatic fever, of course, looms large there. In these there’s a distinct difference in whereabouts in the algorithm acute rheumatic fever comes. What's changed?

This was one of the key updates in this guideline and what triggered the initial review. The treatment is stratified based on the patient's risk of acute rheumatic fever in the first instance. So that patients at a high risk of acute rheumatic fever, it's recommended that they're treated with empiric antibiotic therapy, regardless of whether or not the clinical features are suggestive of a viral infection.

And obviously that does always need to be balanced against antimicrobial stewardship principles. However, it felt that the risk of not treating and missing group A strep in this context was more significant than the risk of over antibiotic prescribing. And it's probably important to emphasise that this is only a very select group of patients.

The use of guidelines is interesting. So, certainly 98% of people listening to this podcast, I would imagine, would be not working in remote Aboriginal communities. And so therefore it absolutely makes sense if anyone comes in from that community and has a sore throat that you follow this guideline and routinely give them, as it turns out, something like long-acting penicillin. Interestingly, if you actually immerse yourself fully in a remote area, you can't actually follow the guidelines to the letter because the guidelines technically would say that every single person you ever meet, whoever walks into your surgery, who mentions a sore throat, you would give a jab of a needle, which I think does take away a bit of the local assessment and knowledge of that person. And also it makes people stop coming into the clinic when they have a sore throat, cause they don't want a needle. As with most guidelines, you can have a general rule, which is absolutely fine. Although you have to bend it a little, if you are living in that space.

When applying these criteria, one of the key things that we do emphasise is that you also need to rely on the clinical judgement of the clinician who is reviewing the patient, who has expert knowledge, not only in that patient, but in the community and their local epidemiology. I think the other thing to emphasise as well in this particular update, which is a slight difference from the rheumatic heart disease guideline, is that we have provided an upper limit of 40 years of age when stratifying risk, which wasn't something that was in the RHD guideline.

Symptomatic therapy probably hasn't changed much. You're looking at paracetamol and NSAIDs. And if you like, some over-the-counter things to help with the throat. But I think it is worth mentioning to people because not everyone knows that there is now I think good evidence for a very short, possibly even a single dose of an oral steroid to try to reduce that severe inflammatory pain.

There was a Cochrane review that supported that. But yeah, look, to be honest, not much has really changed in this space, in this particular update.

So, we are talking there about 50 mg of prednisone in an adult or 1 mg per kilo for a child, which is a familiar dose to most GPs. Okay. So, let's get on now to management of pharyngitis and tonsillitis. And we are talking now in the person who's not in that unusual situation of being high risk for rheumatic fever, but everyone else. How do we approach that?

Really the key thing is to not prescribe antibiotics for viral pharyngitis and tonsillitis in the first instance. So, that really is those features that we talked about earlier. If you're looking at the patient, you think this is viral, then you do not prescribe antibiotics in this setting.

Antibiotic prescribing in sore throat in primary care is a huge driver for antibiotic prescription, but really there should only be a narrow group of patients that actually require antibiotics. Even those patients where you are suspicious that this could be a streptococcal infection, antibiotics only shorten the duration of symptoms by less than a day. And when you get out to day seven, then there's no difference in improvement in patients who have or haven't had antibiotics. So really you have to balance that small risk of benefit of giving antibiotic therapy in this particular patient group to the potential harms, which obviously extend from the harms of adverse events associated with antibiotics to potentially the impacts on gut microbiome and more serious consequences like antimicrobial resistance and C. diff infection etc.

So, really most patients who aren't at high risk for acute rheumatic fever don't need antibiotics. But then as a GP, you'll realise that there's a lot of steps you need to take with the patient to work out maybe this is a patient that might need antibiotics, but also how do you make that decision together so that the patient feels that their expectations have been addressed and they've been listened to.

The antibiotics themselves, I don't think have changed. So, it's basically phenoxymethylpenicillin orally is the ideal and amoxicillin as an alternative.

Yeah, so actually the amoxicillin is new in the guidelines. It's not necessarily new in all guidelines for sore throat, but they've previously been concern about the prescription of amoxicillin in sore throat, in the patients who potentially had concurrent EBV infection and the risk of rash.

But there's been more evidence published recently that this risk is pretty low and potentially may be related to older formulations of ampicillin. And it's less of an issue with amoxicillin if in that patient cohort that are at risk of EBV infection. And so we still prefer phenoxymethylpenicillin over amoxicillin because it's a narrower spectrum. Children may not tolerate the liquid formulation, because I don't think it tastes particularly good, and so that's a group of patients that you could potentially give amoxicillin to instead and avoid the broader spectrum agents, which seem to crop up quite frequently in audits of antibiotic use in this cohort like macrolides like azithromycin, roxithromycin.

Yeah. Interesting. And certainly sometimes useful. Occasionally phenoxymethylpenicillin is unavailable for a little while too, so that's-

Right. Yeah.

... that's handy. And I also note it can be given twice a day. So when I started out in medicine, I was told it always had to be four times a day, but whether anyone ever took it four times a day for longer than the first day when they were sick is another matter.

The main recommendation still is to give it for 10 days. How many people actually continue it out for 10 days once they're feeling better? But really that 10 days is for microbial clearance and for symptomatic improvement, five days is probably sufficient. And so we have included a recommendation that if you're not in that cohort of patients at high risk of acute rheumatic fever, where you're trying to get pharyngeal clearance of the bacteria, then you could potentially give a shorter duration, which I expect in reality, many patients actually take anyway.

Well, Dr Emily Tucker, it has been a pleasure talking to you and we've learned a lot about very little, I think. It’s a small topic but there’s a surprising amount to talk about and again I find it fascinating just because we do genuinely spend so much of our career dealing with it. So thank you very much for coming along and updating us with the latest TG Sore throat guidelines.

No worries. Thanks for having me.

[Music]

My guests’ views are their own and don’t represent Australian Prescriber and my views are certainly all mine.