Wee Need to Talk About UTIs

The For Kidneys Sake podcast series is brought to you by Imperial College Healthcare NHS Trust and North West London Integrated Care Board (NWL NHS)

How confident are you that the patient in front of you really has a urinary tract infection?

In this episode of For Kidneys Sake, consultant nephrologists Jeremy Levy and Andrew Frankel tackle one of the most common yet surprisingly complex conditions seen in primary care: urinary tract infections (UTIs). They explore why diagnosing a UTI is often less straightforward than it appears, emphasising the importance of symptoms over urine dipsticks and cultures alone. The discussion highlights the risks of overdiagnosis, particularly in older adults and those with asymptomatic bacteriuria, and explains when urine cultures can add value to clinical decision-making. 

The conversation also focuses on practical treatment strategies, especially for patients with chronic kidney disease. Jeremy and Andrew discuss antibiotic selection, the limitations of commonly used treatments such as nitrofurantoin and trimethoprim in CKD, and how to approach recurrent or complicated infections. They share evidence-based prevention strategies, review red-flag symptoms that require urgent assessment, and look ahead to emerging options such as vaccines for recurrent UTIs. 

5 Key Takeaways

• Diagnose UTIs primarily through symptoms, using urine tests to support rather than drive decision-making. 
• Avoid treating asymptomatic bacteriuria except in specific circumstances such as pregnancy. 
• Consider kidney function when selecting antibiotics, as some commonly used agents may be ineffective or harmful in CKD. 
• Recurrent UTIs warrant further investigation, including imaging and preventive strategies. 
• Fever, systemic illness, or severe flank pain should raise concern for more serious infection and prompt urgent assessment. 

The purpose of this podcast is to inform and educate health care professionals working in the primary care and community setting. The content is evidence based and consistent with NICE guidelines and North West Guidelines available at the time of publication.

The content of this podcast does not constitute medical advice and it is not intended to function as a substitute for a healthcare practitioner’s judgement.

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Transcript

Joana Teles 

For Kidney's Sake makes kidney disease management easy. For Kidneys Sake is for primary care clinicians. For Kidney's Sake is nice, consistent, short and sweet. Welcome to For Kidneys Sake brought to you by Northwest London NHS Kidney Care Team.

Jeremy 

Hi, I'm Jeremy Levy, Consultant Nephrologist at Imperial NHS Trust.

Andrew

And hello, I'm Andrew Frankel, a colleague of Jeremy's, also a consultant nephrologist at Imperial College Healthcare NHS Trust. And this is another podcast in the series of For Kidneys' Sake. Today, we're gonna talk about something that clinicians in primary care see very frequently, urinary tract infections. And you, our audience, are all probably much more expert than Jeremy and I but we thought we would add some comments about UTI particularly in association with CKD and other kidney issues but also some more general comments about UTI. And by UTI, urinary tract infections, I mean infections of the lower urinary tract and essentially I'm referring to bladder infections and not more complicated infections such as pyelonephritis or in men prostatitis. And despite how common your urinary tract infections are, there is still quite a great deal of variation in how they are diagnosed and managed.

Jeremy 

Yeah, not quite a lot of variation, a huge amount of variation, Andrew. And I want to reinforce what you said earlier. I think our audience will probably know more about this than we do, but we think it's really helpful to make some comments, especially in context of chronic kidney disease. And as you say, it sort of appears straightforward, but when you start to look at the details, there's just huge amounts of uncertainty around this whole area. So the biggest challenge.

First off really is that first question, is this actually in the person in front of you a urinary tract infection? And actually in reality, we all know that a true urinary infection is often a clinical diagnosis without needing any sort of laboratory support. And that's based on a patient's symptoms. They've got new onset dysuria, burning when they pass urine, urinary frequency, some urgency with or without pain. And in those sorts of cases, a patient presenting like that, they may not need any lab testing of any sort to diagnose a urinary infection. And in some of those patients, actually, if you end up with a sort of dipstick that doesn't quite fit your clinical picture, actually, you might actually not make the right diagnosis. And the other way around, often patients have got asymptomatic bacteriuria and they don't have an infection and we might be doing more harm by treating. So this is quite tricky, isn't it? Separation of symptoms from urinary testing, which we both talked about before.

Yes, so I agree it's a difficult situation but I think I'm to take away a key message here that you've given which is the importance of symptoms and yet the importance of also being cautious about over treating or treating asymptomatic bacteriuria. Although my understanding, although I'm not an expert, is that in pregnant women you do treat asymptomatic bacteriuria with antibiotics but not in the general population. Isn't there a flip side, Jeremy, in that patients with non-specific symptoms, particularly older adults, we can easily overdiagnose UTIs. So the second key question is when should people be sending urine for culture?

Jeremy

I think that's exactly right, Andrew. And then, course, poor GPs and primary care get hit by the fact that the new confusion might be driven by possibly a urinary tract infection, even if there was no other symptoms. So that issue, when to send urine culture so you don't overdiagnose urinary tractions and when to interpret the results. And your previous point was absolutely right, that issue about asymptomatic bacteriuria. So when to send urine for culture. So I think that particularly in elderly and post menopausal women where we really want to make sure people really have got a true urinary infection. That's where problems really arise. So in younger women with symptoms it's a bit easier and you won't need to send urine cultures at all but it's much more important I think in often in older people in people with recurrent symptoms or even labeled as having recurrent urinary infections.

Certainly in pregnancy for the reasons you mentioned about asymptomatic bacterial urea or whether there's diagnostic uncertainty. But of course sending a urine culture you don't get the results straight away. It might take two, three days. So that's why back to that first point the importance of how the patient presents and the symptoms. So yes send urine cultures I think in older women who've got symptoms in those with recurrent symptoms or recurrent infections where you think treatment might have failed and certainly in pregnancy.

Andrew  

So Jeremy, what about something which is a foundation of investigation and clinical assessment in primary care for these symptoms which is dipstick of the urine? Where does that fit in?

Jeremy 

So exactly, they're easy to do and you get an answer straight away. And of course, the multi sticks have got those multiple colored bars and they include leukocytes and nitrites as well as, of course, blood and protein. And of course, they can be helpful. But again, I think it is in the context of the patient in front of you and their symptoms. And they're not definitive and they're much less reliable in old adults. And of course, anybody who's got a catheter, whether it's a permanent catheter or they're intermittent catheterisation, Actually bits of blood, bits of protein would be expected and are not helpful but if a dipstick's got a positive leukocyte and nitrite and a little bit of protein that can be really helpful but people can have infections with essentially relatively clear urine dipsticks and vice versa

Andrew 

So I'm not sure that we've necessarily helped primary care there other than highlighting some of real difficulties in diagnosis. But let's just say we have confirmed that this is a urinary tract infection. next key question for me is who actually needs antibiotics and which ones to use? Presumably patients with clear urinary symptoms will usually benefit from antibiotics. But in milder cases or where there is uncertainty, a delay in prescribing while culture results are attained, I suppose, would be useful. What I think is crucial is recognising when not to treat, particularly as you have suggested in asymptomatic bacteriuria hence again reinforcing the need to match symptoms with, when it's appropriate, the appropriate diagnostic tests. And in many people with minor symptoms, they can be given antibiotics, but they can be asked to defer starting them if symptoms improve over two to three days without the antibiotics. So let's now think about which antibiotics for how long.

Jeremy 

Yeah, but I'll reinforce that last point you made, Andrew. And I think that's more and more being done, particularly patients with relatively minor symptoms, but they sound like a urinary infection. Actually, it can be so pragmatic and easy to give somebody a course of antibiotics, but say, well, wait two or three days, because if everything resolves on its own, you won't need them. And that avoids overprescribing, but also saves the patient having to come back a second time to primary care and then get another prescription. So that can be a really pragmatic and useful way forward.

So which antibiotics? Well, actually, at least this is one area where I think we now have really some very good evidence. Doesn't mean that everybody follows it, but there is good evidence. And again, for uncomplicated, simple urinary infections, which as you implied earlier, this is essentially infection in the bladder, not pyelonephritis, not patients with structurally abnormal kidneys, but simple urinary infections, uncomplicated. And this is not in pregnant women.

A short course of three days is usually sufficient and you don't need longer courses of antibiotics. But then we have this issue of patients with chronic kidney disease. And this then becomes really important because the first line antibiotics and this varies around the world and in different areas, but often is either nitrofuranotone or trimethoprim, both of which are very good antibiotics in most areas for simple

Andrew 

A short course of three days is usually sufficient and you don't need longer to get the contact.

Jeremy 

urinary infections. But in CKD, chronic kidney disease, we have a problem. Nitrofuranthione is much less effective as the GFR declines and probably has no benefit in terms of getting into the urine and clearing infections once the GFR is less than 30 and has an increased risk of neuropathy. So nitrofuranthione really shouldn't be used if the GFR is less than about 45. So that's one antibiotic in CKD we're really not recommending anybody uses.

Andrew 

Absolutely, I'm going to spoil things now by highlighting that the second most commonly used drug, trimethoprine, has its own problems, which we have discussed on a number of occasions in these podcasts. Trimethoprine also blocks the excretion of creatinine in the kidney tubule, thereby elevating the level of creatinine, even though the GFR hasn't changed. So you will note a reduction reduction in GFR which is artifactual, not real, and reversible when you stop the trimethoprine but causes confusion if the GFR has been measured. And you don't of course need to measure GFR in people who have got uncomplicated lower unit tract infections but they may be having concomitant bloods for other reasons. And this effect is much greater the lower the GFR and causes significant problems and is not an unusual or rare reason people are referred to the nephrology services. Also, however, and perhaps more importantly, trimethoprine can impair potassium excretion and patients become significantly hyperkalemic, particularly if they are starting at risk of this. Therefore, trimethoprine should probably be avoided in people with more advanced chronic kidney disease and particularly those at risk of hyperkalemia.

Jeremy 

So you're causing us problems, Andrew. We can't use trimethyprime in advanced CKD and we can't use naturopherotone even in moderate CKD. So actually, what do we do in terms of antibiotics in chronic kidney disease? Well, in the UK, certainly, and in many other places, the first choices then become one of two antibiotics. The one is pivmesicillinam and the other is Fosfomycin. And these, in general, are very effective. But again,

We should remind everybody local sensitivities of common bugs may well vary. And in most areas of the UK, Europe, parts of the world, often primary care and community services will know sensitivities of common bacteria. But first line, certainly pivmesicillinam. And that's a three day course for uncomplicated urine retracting infections. And Fosfomycin is a lot easier. It's a single dose of Fosfomycin. And that's been recommended as a very good first line treatment over older antibiotics in uncomplicated urinary tract infection. And of course, for patients, it's very easy, a single dose of an antibiotic. We've talked about women a lot. should just, of course, don't forget men can get urinary infections. The difference here is we get worried about infection within the prostate gland and whether it actually isn't simple and straightforward. And men need a one week course of antibiotics, not three days. And that's so we can get good penetration around the prostate, but very clear consideration of whether they have prostatitis and might need ultrasound or further investigations as to why they've had a urinary infection, whereas in women it's much more common, of course, for anatomical reasons.

Andrew 

We're banding around this term uncomplicated. So let me put this to you Jeremy, perhaps we should tell the audience what do we think are complicated UTIs.

Jeremy

You're right, Andrew, it's an important distinction for the reasons we've alluded to in last five minutes. So complicated doesn't mean your patient's irritating. Complicated means pregnant women. And of course, they're not complicated per se, but it affects when to think about infections, what to use. So pregnant women with a possible urine infection counts as complicated. Men with symptoms of urine infection also labeled complicated because of that issue of thinking about other issues. And anybody who's known to have structural abnormalities of their urinary tract. They may have congenitally abnormal systems, previous reflux, but something structurally wrong and or for example, stone disease and actually patients with catheters because then separating symptoms and changes on urine dipstick from true infections is not straightforward. So that group are complicated urinary infections, pregnant women, men, people with structural abnormalities and people with catheters overall.

 And those people, ⁓ doctors, clinicians, nurses need to think about a different threshold for antibiotic treatment and investigations because you may need to do more. And in some of those patients might be appropriate for referral to secondary care. And we should both say, we, Andrew? Usually this actually should be urology, not nephrology. Urologists on average are better at dealing with complicated urinary infections where there's structural abnormalities in the urinary tract than nephrologists. But...in those circumstances, pick your favourite flavour of specialist local to you.

Andrew 

Agreed completely. So the other issue that comes up a lot and does come to us as nephrologists is usually women with recurrent UTIs. These do get referred to the secretary care. Any thoughts about that issue?

Jeremy 

Yeah, and you're right, Andrew, this is actually really quite a common referral pattern and it could go either way. And of course, some areas have got gynaecologists interested in Euro gynaecology. So a range of secondary care specialists might see particularly women with recurrent and often confirmed your infections. But first step would be are these definitely urine infections actually establishing that in this context of recurrent symptoms will be very important.

And by recurrent, we usually mean two or more infections within a six month period or three urinary infections within a year. So that would count as recurrent urinary infections. And in all those patients, it is really important to get imaging of the kidneys and the bladder to see whether there is structural abnormalities, possibilities of things like congenital bladder and ureteric disease or even asymptomatic stone disease.

Kidney stones or bladder stones, which are less common in the UK, would all increase your risk of infections and bladders that are structurally abnormal and don't empty properly. So recurrent urinary infections definitely need imaging and ultrasound is easy and the first step. And if there are stones, needs urology to help resolve. And if there are structural abnormalities, might well influence the length of antibiotics needed or whether prophylactic. Antibiotics are needed So that's the first step. Imaging if there's recurrent infections. If there's no imaging abnormalities seen, then the next thing is thinking about, well, how to prevent it. And simple behavioural advice might be useful. So for women, for example, that could be emptying their bladder, going to the loo after they've had sex, and that can reduce actually infections that can be driven by sexual activity. And in older post-menopausal women,

The critical first step which can be really effective is using vaginal estrogen. So postmenopausal women, vaginal estrogen, and that can be creams or pessaries, a variety of forms, is really helpful. Really evidence-based, dramatic reduction in urine infections. That should be your first step. And then we move on to slightly more complicated things. And there's a after those two steps of either prophylactic antibiotics or this thing called Hiprex or methenamine. So, Hiprex or methenamine is not an antibiotic. It's sort of an antiseptic and it clears bacteriuria from the bladder but not as an antibiotic. So, you never get resistance. It's taken daily not to treat but to prevent infections and it is really pretty effective. So, Hiprex or methenamine can be used widely to try and prevent infections and the alternative would be prophylactic antibiotics and that can be either low dose for example trimethoprim at night often and often for three to six months taken every day and can be really quite effective and sometimes we do rotating antibiotics so one month of trimethoprim one month of amoxicillin one month of kefalexin for example each for a month and do that for six months that most people would go for a single antibiotic first if infections break through then try rotating

 That way you save Fosfomycin and pythicin for true infections, breakthrough infections, and you're saving those in reserve. So I think those are the really useful clues about recurrent. But in that context, culture culture is really important because then we know what bacteriuria we're dealing with and what the likely sensitivities are.

Andrew 

Those are the really easy ones.

That's really helpful, Jeremy, thank you very much. one of the other things that we do need to highlight, of course, is that we've been talking about lower urinary tract bladder infections. But we must bear in mind situations where these lower urinary tract infections can become more serious and key red flags would be the association with systemic illness and features that suggest that the patient has developed pyelonephritis, sepsis or obstruction because in that situation we move to a much more urgent requirement for assessment and maybe even in the emergency services. So you should always ensure that patients are given safety netting to understand what symptoms require them to seek further help and what symptoms to particularly look out for in that regard.

Jeremy 

You're absolutely right Andrew, the key symptom is high fever isn't it? mean normally lower urinary tract infections don't cause me a major febrile episode so people who are getting severe fevers, not even severe fevers but febrile episodes or they're feeling unwell, dropping their blood pressure, feeling dizzy or get severe loin pain which shouldn't occur with simple urinary infections seek medical advice might well be not a simple lower urinary tract infection and from that serious end just back to preventing

Lots of people say I'll drink cranberry juice and I'm afraid the advice is that's just rubbish. Cranberry juice that most people buy in shops is not cranberry juice. It's cranberry juice drink. It's a sugar solution with a little bit of cranberry added and all it does is make you fat and your teeth sticky and does absolutely nothing. There are some trials of using cranberries concentrated supplements ⁓ but actually none of the trials show good evidence this works.

Most people don't keep taking them and they're not very effective. So cranberry, I really wouldn't recommend and cranberry juice drink is absolutely of no benefit whatsoever. But what is getting very exciting and I'm seeing it more and more used, but not yet available in many places is vaccines. So for people with recurrent infections, there are now some very interesting and likely effective vaccines that actually prevent infections after a course. And the one that's been more widely used is called Urimune.

I don't think it's yet available in the NHS sadly, but it does actually essentially mount an immune response in your bladder against infections and can be very effective, but not widely available yet. Andrew, we've had a great conversation. You need to summarise all of that in three bullet points, don't you? 

Andrew 

Well, that is an impossible task, but I'm going to give the audience my three sort key takeaways. Diagnose UTIs clinically, not just based on urine tests. So it's clinical in conjunction with the urine tests and the patient in front of you. Don't treat asymptomatic bacteriuria other than in pregnant women and be particularly cautious about this in the older patients. Use antibiotics appropriately as we have discussed and for the right duration.

Jeremy 

Fantastic. Three very simple points even though we've been speaking for about 15 minutes. Really really helpful. I'm going to remind people about Hiprex because I think that is a useful thing to try for preventing infections as well. I think this has been a useful chat. I hope we haven't confused people more. I hope we've given people some top tips about your infections especially with chronic kidney disease.

Andrew 

Well I certainly feel I've learnt a bit from talking to you about this Jeremy as I usually do. So thank you very much and thanks to the audience and we look forward to engaging with you again on our next For Kidneys Sake podcast. Goodbye.

Jeremy

Bye.