This StAR episode features the CID State-of-the-Art Review on evaluation and management of diabetes-related foot infections.

Our guest stars this episode are:

Dr. Meghan Brennan (ID physician at University of Wisconsin)

Dr. Marcos Schechter (ID physician at Emory University)

Dr. Tze-Woei Tan (Vascular surgeon at University of Southern California)

Dr. David Armstrong (Podiatric surgeon at University of Southern California)

Journal article link: Nicolas W Cortes-Penfield, David G Armstrong, Meghan B Brennan, Maya Fayfman, Jonathan H Ryder, Tze-Woei Tan, Marcos C Schechter, Evaluation and Management of Diabetes-related Foot Infections, Clinical Infectious Diseases, Volume 77, Issue 3, 1 August 2023, Pages e1–e13, https://doi.org/10.1093/cid/ciad255

Journal companion article - Executive summary link: https://academic.oup.com/cid/article/77/3/335/7242512

From Clinical Infectious Diseases

Episodes | Consult Notes | Subscribe | Twitter | Merch | febrilepodcast@gmail.com

Febrile is produced with support from the Infectious Diseases Society of America (IDSA)

Hi, everyone.

Welcome to Febrile, a cultured podcast about all things infectious disease.

We use consult questions to dive into ID clinical reasoning, diagnostics, and antimicrobial management.

I'm Sara Dong, your host and a MedPeds ID doc.

Welcome to the very first Febrile StAR episode.

These will feature topics and authors from the CID, so Clinical Infectious Diseases Journal State of the Art Reviews.

You can listen to our last episode, number 97, to hear from the editors of these reviews, and we'll be bringing you four straight weeks of star episodes to kick this off.

I'll introduce our guest stars today.

Dr.

Meghan Brennan is an infectious diseases physician and health services researcher at the University of Wisconsin with a joint appointment at the VA hospital.

Hi, my name is Meghan Brennan.

Nice to be here.

Dr.

Marcos Schechter is an infectious diseases physician and assistant professor at Emory University School of Medicine.

Hi, my name is Marcos Schechter.

I'm an infectious disease at Emory, practice at Grady in downtown Atlanta and good to be here with the crew.

Dr.

Tze-Woei Tan is an Associate Professor of Clinical Surgery and Director of the Limb Salvage Research Program at Keck Medicine of the University of Southern California, USC.

He is double board certified in vascular surgery and general surgery.

Tze-Woei Tan: Hi, my name is Tze-Woei.

I am a vascular surgeon at USC.

Happy to be here.

Dr.

David Armstrong is professor of surgery with tenure also at Keck Medicine at the University of Southern California, and he is an internationally recognized leader in the field of podiatry, diabetic foot, limb preservation, tissue repair, and wound healing.

I'm David Armstrong, I am a professor of surgery, a toe doctor at the Keck School of Medicine of University of Southern California in beautiful, sunny Southern California where even when it's not sunny, oh it's sunny, it's sunny.

Uh, well, thank you guys all for joining.

Before we talk about medical things, though, uh, Febrile is everyone's favorite cultured podcast.

So we always ask our guests to share a little piece of culture that brings you happiness, basically just something, uh, non medical.

So I'd love to hear it.

What, what kind of interest do you guys have?

It's spring here in Wisconsin, so I was thrilled to see my first robin last week.

Very nice.

Um, it's funny, in the era of podcasts, I stopped listening to music for a while, but I've rediscovered music recently, and I've been listening a lot to an album called 1988 by a pianist called Michel Camillo, who is a jazz guy, and I used to listen to that album from my dad's records.

Just listening to that guy has been really good and getting myself back into music's been nice.

Well, I've loved podcasts since they were actually on Short Wave, and actually one of my favorite podcasts is still one of the oldest and it's with a guy named Melvyn Bragg, uh, and I would tell everyone to go out and grab this.

It's called "In Our Time" and it's on BBC.

It used to be on the BBC home service, Radio 4, and I used to listen to it way back in the day in the 90s and 2000s, um, and, uh, they've had over 1, 000 podcasts now.

And the last one just yesterday, every Thursday at 9 a.

m.

Greenwich Mean Time, they broadcast them.

It could be anything from, uh, particle physics to yesterday was Alice's Adventures in Wonderland, talking about Charles Dodgson.

Uh, also known as Lewis Carroll, uh, and he has one of my favorite quotes, which is, uh, don't just do something, stand there.

And I think when we stand there and we regard what we do, a lot of what we do is pretty good, but some of the things we do, we could probably improve on.

That's why it is the practice of medicine and surgery and nursing.

And that's why, Sara, you put all these really smart and some of us less smart characters to try to mix it up in the Petri dish, uh, or at least the sonic Petri dish.

So here's to that.

Excellent references.

And closing us out, Tze-Woei.

Tze-Woei Tan: I enjoy traveling.

Uh, I enjoy experience different cultures.

And I actually also, uh, enjoy listening to Dr.

Armstrong talking so that all of us don't have to talk too much.

Tze-Woei, why say it in two words?

Dr.

Tan, when you can say it in 200, that's what I say.

Oh, well, thank you.

We got some good recommendations.

So you all are on the show.

I want to thank you for creating this article, so State of the Art Review: evaluation and management of diabetes related foot infections, which I know brings together ID, endocrinology, podiatry and vascular surgery.

And I have sort of a representative case, but I wanted to just start by having you share a little introduction or some perspective of the, I'm going to say DFI throughout the podcast.

So everyone knows and the goals that you had when you were writing this review.

Well, I think a big selling point for me was to try to write a review that was more all encompassing and taking a step back from any one specific facet, because it really is like a puzzle piece and infectious disease and antibiotics is just one small part, uh, you can't treat the whole thing just from one discipline.

I was just excited to spend December at my mom's house.

I was in Brazil sitting, you know, eating food over Christmas and I would log in and Nico, Jonathan, Megan, everybody would be there just typing and I would see their little thing that they were typing there.

It's beautiful.

Oh man, you're making me wax nostalgic about churrascarias.

I think that this problem is often a lemon on everyone's 10 most important things, you know.

We have this problem that's often covered by a shoe at the end of the body, you know, the end of the anatomic peninsula, and folks often just ignore it until it's too often, too difficult to ignore.

Coming together like this in an interdisciplinary way, I think, is really life affirming.

Tze-Woei Tan: All of the people in this podcast talk about how much they hate amputation.

I think I'm the only one that get to do the amputation, so I think, uh, if I don't have to do another amputation in my career, they'll be great.

Love it.

So, I put together a sort of made up case, but just something to give us a chance to talk about a lot of the concepts that you covered in the review.

So, we'll meet our patient.

He's a 50 year old male.

Has a long standing history of insulin dependent diabetes, hypertension, coronary artery disease, and CKD.

He presents with about one week of left foot swelling and discoloration.

You know, he says, I might've stubbed my toe in the past.

I'm not really sure.

His physical exam today shows cellulitis in his left foot extending to about the ankle, as well as an ulcer on the plantar surface of the fifth toe around the metatarsal head.

And there is a small amount of purulent discharge.

His vitals are stable.

He is afebrile with a temp of 37.

8 Celsius.

The initial x ray is unrevealing.

The initial peripheral pulses were not appreciated due to foot swelling, but a Doppler did show signal in the dorsalis pedis and posterior tibial arteries.

On his labs, we have a leukocytosis with a white count of 17, 000, a sedimentation rate of 92, that's the millimeters per hour, CRP 200 milligrams per liter.

His blood glucose is 200 and his A1c is 12.5%.

And then I mentioned that he had CKD, his creatinine is 1.

6.

Uh, so I'm going to pause here first because you provide information in the article about how diabetic foot ulcers are classified and specifically the Society for Vascular Surgery's Wound Ischemia Foot Infection Classification System and really sort of framing it,

particularly for, I think, us in ID.

And so most of the Febrile audience is probably ID trainees and docs.

And I would love sort of an introduction or perspective on using that classification system and any other thoughts you might have.

Well, since I'm farthest away from the center of the body, I'll get started.

In the toes.

So the reason that we use something like wound ischemia and foot infection or WIfI.

People thought when we came up with that, uh, acronym that it was me that actually came up with the acronym, right?

It wasn't.

It was my flo-migo prime, Joe Mills, uh, who's now the President of the Society for Vascular Surgery.

It was a real stroke of brilliance, but we often will compare this problem unfavorably, unfortunately, to cancer.

Morbidity and mortality is similar to cancer.

Cost, believe it or not, is more expensive than the five most expensive cancers in the United States.

But we don't really talk about this problem, which can be profoundly life shortening like cancer.

And so to do that, we wanted to try to create a common language, common language of risk.

So with cancer, you know, you have tumor, node, metastasis, TNM.

And you grade those, you know, a mild, moderate, severe for tumor node metastasis, and then you come up with your stage, um, and you can have some modicum of predictability.

Same thing with WIfI.

It's just wound, that's tissue loss, ischemia, and then foot infection.

And so for the foot infection portion of it, this is the IDSA's classification that has been around now for a long time.

Um, my friend Larry Lavery and I, we, we worked on about 20 years ago, validating that, um, after it was first described by Ben, my old long time buddy, Ben Lipsky et al, uh, a few years earlier.

So that classification's in there, none, mild, moderate, severe.

For the wound, it's just none, mild, moderate, severe.

And for ischemia, it's none, mild, moderate, and severe, based on Uh, hemodynamics or tissue perfusion, take your pick, and each of those individually is predictive, but when you combine all of them, it's super predictive.

And the other cool thing about it is that it helps us say, okay, what is dominant?

Is this just a tissue loss dominant, just a wound dominant condition?

If that's the case, great.

Just take care of the wound.

Patient doesn't need to be in hospital.

We can protect the wound.

We can offload it.

We can debride it.

We can skin graft it as we need to.

If it is an ischemia dominant condition, well, that is the purview of Professor Tan.

Uh, one improves the flow.

Um, and then of course the patient can be discharged.

Or if it's a foot infection, an infection dominant condition, then that needs to be taken care of.

Typically, the infection, you'll be happy to know all of you in ID, culturally, it typically supersedes all of the other problems like tissue loss and ischemia, generally speaking.

But the complicating part of this is that they're all together, like a big Venn diagram of bad.

And it's always changing.

And the key is to be able to communicate this to your flo-migos, and your toe-migos, uh, as, uh, as infectious disease doctors, uh, with your entire team and the family.

Um, and that's kind of the big enchilada.

Tze-Woei Tan: I think there's a lot of adoption from vascular and podiatry for the WIfI classification.

Since this is a podcast for the ID doctor, and I want to ask, you know, whether the system is used widely in the ID world and what are the, some of the barrier of using it?

So, I used to use Wagner and I did morph over to WIfI.

I think Wagner was pretty easy from an infectious disease standpoint because it was so infectious centric.

I like WIfI a lot because it helps me in particular pay attention to the ischemic portion that was definitely missing in Wagner.

You know, they had a little bit of wound, but definitely wasn't taking into as much account for ischemia.

And the way I kind of overcame it is I kind of looked a little geeky for a while, but I put that, you could almost cut out these tables and just post it above your, your computer screen or bring it up on a screen and figure out an image really quickly to reference and then just run through it and it's pretty, it's pretty self explanatory and pretty quick.

And then it really does help create that, you know, as Dr.

Armstrong would say, lingua franca between all the services so that everybody's on the same page much more quickly.

I, I would take even of a more proximal step about what Tze-Woei is asking.

I think a lot of us don't even use the IDSA infection classification system.

Let's just start from there.

People look at an ulcer and they're like, bad, good, medium, right?

And they say vanc[omycin] and zosyn (piperacillin-tazobactam) vs.

IV versus oral, like, as if that meant anything.

So I would say, even as a step back, if we just use the IDSA system to decide if something is infected or not, that would be so wonderful.

And I actually have just a plugin for the Society of Vascular Surgery app.

I have it on my phone.

Has a WIfI calculator.

I use it all the time.

And here at Grady, we built it into Epic, too, so people can use it.

Not that they do, but it's there.

Well, yeah, but you can also use a dot phrase.

I can't believe I'm getting dot phrases into a podcast now.

It's almost like, that must be a sign of the apocalypse.

Or toe-pocalypse.

Okay, but the point is the, uh, yeah, we just have a quick dot, dot wifi and it, uh, it puts it all out there.

And then what we do is super easy.

We just bold none, mild, moderate, severe for wound ischemia and foot infection.

And by the way, you know, Marcos, if you're saying none, you were saying bad, medium, good, uh, well you have three quarters of the IDSA system there, it's none, mild, moderate, severe.

So, just like, just like the ischemia and the foot infection, it's just 0,1,2,3 for all these.

It actually is really simple and elegant.

When you start using this kind of thing, you just want to ask, like, what's dominant?

Like, what's the dominant problem?

And so that's the way that our trainees communicate.

They say, this is an ischemia dominant condition.

This is an infection dominant condition.

Oh, this is just tissue loss.

Great, we can discharge the patient, but that's the kind of conversations that we see happening between ID, between vascular, between podiatry.

To your point, I think what I see the most in the hospital is ischemia and wound dominant conditions all become bad, and bad means vanc[omycin] and zosyn (piperacillin-tazobactam) right?

Which in a patient with CKD is creating problems.

We just finished grand rounds that Tze-Woei just gave, and we had M& M before that, and in M& M, Uh, there were, there were several, I mean, obviously with vascular, there can be some real flow-tastrophes, as we say, and, uh, and one of the big ones that we were looking at was, uh, patients that ultimately had C.

diff that was completely avoidable, right?

If, uh, if there was a consistent interdisciplinary approach to looking after this patient's antimicrobial regime or no antimicrobial regime.

And I think what a lot of people, especially non ID doctors, don't appreciate is that you can really hurt people with antibiotics and having respect for these things and don't just prescribe them to treat yourself, treat your patient, I think is the order of the day and, this is the way forward.

Can I ask a quick question to you guys on the ID side?

You know, why are we still using vanc?

It's great, man.

It takes an hour and a half to infuse.

Gotta check levels, causes AKI, and it, it's worse than any other antibiotic for bone and joint infections, how could I not use it?

Well, you guys are making the transitions very easy because I actually was going to throw it to our ID group.

Obviously, we're going to talk about the different components of care here.

So antibiotics, when indicated, surgery, other aspects of care.

Meghan and Marcos, can you talk a little bit about, you know, we get the call on the ID side.

Maybe you hear this patient scenario.

What are you thinking about for infection?

What should we reach for in, in empiric therapy?

And kind of, I guess I should say your, your framework as the ID person and maybe ways that we could improve upon that,

well, the first thing I was gonna ask is whether or not this wound probed to bone, because I think a good, solid, physical exam is underappreciated, and especially in so many of these patients who are insensate, you know, you don't have to really pussyfoot around.

You can go for it, um, and get in there with some sort of a probe and tell me, hey, does it hit bone or not?

And right then we'll have a really good idea of whether this is osteomyelitis.

Yeah, I think this is a pretty interesting prompt because, you know, there's flirtations here that this patient has a significant cellulitis, which generally means we want to start antibiotics sooner than later.

But there's also a hint that they may have osteo[myelitis] based on this ESR of 92, which also means that maybe we don't want to muddle the diagnostics if we ever want to get a bone biopsy.

So I'm with Meghan.

I think this is a case of, you know, let's, let's get a little more, the probe to bone is pretty important in this case.

And as far as antibiotics, these are the ones that I find hard curbsiding.

I don't curbside skin and soft tissue infection consults.

I go and see them.

I can curbside pneumonia all day.

Uh, cellulitis, I need to go see this patient.

And if they look okay, you know, I might want to do a probe to bone and hear a little bit more.

If they don't look okay, I would start antibiotics right away.

And then you need to know if your area where MRSA worries you or not as a first step.

I agree.

I'm just kind of fangirling for infectious disease because, you know, and again, not to blow sunshine here on an ID centric kind of podcast, but there are very few specialties that I see externally that, that doctor that really looked after their patients, uh, you know, from stem to stern like ID do.

I know Marcos was complaining to the opposite, uh, but, uh, in my experience over a long time at a lot of different hospitals, ID has been, you know, just uniformly the doctor's doctor.

So there's that.

So you start from there, but just to kind of bring it out there to talk about osteomyelitis, you know, I think in the foot, people tend to make a big deal about osteomyelitis.

But, you know, I would ask everyone here, is it really a big deal?

I mean, it doesn't wake us up at night.

It's not like some urgent surgical imperative.

And generally speaking, in the foot, most of the time, uh, osteomyelitis.

is, is actually there because of, because of a wound.

So you have a continuous source, contiguous source, uh, and that wound is there, not because of an infection, that wound is there because of, generally speaking, repetitive stress and a deformity.

So I would argue, usually, uh, osteomyelitis is really a mechanical problem in the foot.

In other places it's obviously different, especially, and also in kids, but in the foot it's generally a mechanical problem.

So very often this can be treated, especially if it's fulminant, uh, surgically, and one could get back to a clean margin, just like one would do in cancer, um, one can rapidly de escalate from all of this poly antimicrobial to just oral, if someone has a functioning gut, and then stop antibiotics.

Since it is Febrile, I'm going to ask, uh, Megan and Marcus, just to, for especially earlier learners, thinking about microbiology, not necessarily this patient, but microbiology of diabetic foot infections.

I think over 80 percent of them are polymicrobial.

So, you are kind of trying to potentially cover a zoo.

I think the things that come up are, do you need MRSA coverage and do you need pseudomonal coverage?

And in cases where the patient is not septic, uh, I would argue that I think depending on where you are in the region, about 10 percent of them have Pseudomonas.

I'm not sure you need the pseudomonal coverage, um, right off the bat for somebody that's hemodynamically stable, and maybe I'll leave MRSA to Marcos.

Yeah, just to, also in the microbiology, I think one of the things where the, um, infection classification helps is it also has a correlation with microbiology, or mild infections are generally only gram positives.

And then as you go to moderate, severe, start adding gram negatives to the mix and anaerobes once you become severe.

At Grady, we have lots of community acquired MRSAs, so it's something we worry about.

I should mention there is a big, I think, VA study out there where they did nasal swabs for MRSA and checking the wounds.

If you read the abstract, it'll say there are, great negative predictive value, positive predictive value, but you need to get it to fine print.

Because predictive values, of course, depend on your local prevalence, right?

So the sensitivity and specificity was not that great depending on where you are and how cautious you want to be about it.

And the whole issue of Pseudomonas, I think, depends a lot where you are in the world.

Uh, in case there are international people here, there's, you know, in Turkey and other warmer places, found a lot of Pseudomonas in feet.

Uh, and also prior antibiotic exposure is something that I think about a lot.

Is this somebody who received IV antibiotics in the last 30 to 90 days?

And also trying to think of this more broadly, we are really lucky to have our surgical friends on this call.

Thank you guys for joining.

And I'm wondering if if you could talk a little bit about, what are the surgical options for treatment for diabetic foot infection, what does that spectrum look like?

What important pieces of information play into your decision making for how to manage these patients?

Well, maybe I could touch on the infection portion, maybe the incision and debridement, and then Tze-Woei could pop in and talk about the latest and greatest data for endo(vascular) and open options for improving folks runoff on the anatomic peninsula for their blood flow.

So for the I&D (incision and debridement), I, I think I'm preaching to the converted when I say that, uh, time, um, is tissue here.

This is one of the few places I think in medicine and surgery, where the most conservative approach actually is a surgical one.

I think it depends on the patient obviously.

There are some patients where it pays to be very, very cautious, but if you're really wondering about is there an abscess there or am I missing it, I think not doing something can be just as problematic as doing something.

So if you have a question about whether that thing probes the bone or not or whether that streaking up the leg, um, is, uh, concerning.

I would take that person to the operating room and open it up.

Now, there are set approaches to opening up the diabetic foot and doing a good quality consistent incision and debridement.

It's almost like approaching a compartment syndrome where you would, uh, where you would release, uh, different compartments of the leg.

Same thing in the foot.

And the foot is, a small, discreet area with a lot of complex bones and joints, like 20 percent of the whole body down there.

So, there's a lot of little nooks and crannies and knowing that and understanding that implicitly is important for the she or he that's going to be going in there and doing the I&D.

But doing that sooner rather than later, I think, is important.

Once one has done a good quality incision and debridement, you've taken good quality cultures, one has altered their course of antimicrobials based on those cultures, then that this problem kind of moves away from being an infection dominant condition and moves toward being, uh, an ischemia dominant condition.

Tze-Woei Tan: Thank you for the setup.

I think before moving into the blood flow, there are some patients with extensive infection, especially if the infection extends above the ankle.

I think those patients would benefit from urgent or emergent open amputation, where we do a guillotine and cut just above the ankle to get rid of the infection and then leave the wound open and come back to revise to a higher below knee amputation once all the infection is resolved.

Going into the blood flow issue after the infection has been addressed, I think the main thing to know is inpatient PAD and we think that they need blood flow for healing, those patients will benefit from some type of procedure to improve the blood flow.

And nowadays we do open or endovascular.

Where open is we use um, bypass using a vein or prosthetic for a bypass versus an endovascular where we use stent or balloon or arterectomy and different techniques to resolve the issue.

I think a recent randomized trial, which is the best endovascular versus open revascularization trial for people with critical limb ischemia, which is PAD with a wound loss or tissue loss and open procedure in a good surgical candidate.

Especially those with a good vein for bypass is better than endovascular.

Uh, for those who is not a surgical candidate or they don't have good vein, that endovascular is acceptable procedure to improve the blood flow.

Just take a step back if you, if you guys, cause I know we're talking about a hypothetical patient and it's hard to visualize, but I just think like in somebody that I'm hearing has, yes, has an extensive cellulitis yes, has leukocytosis.

But otherwise seems stable, you know, I don't know that I would be in a hurry to chop a whole lot off, I think I want to clean things up, I just want to make sure that's absolutely clear to, to everybody listening, and I think cooling them off with antibiotics, and if you can clean things up surgically, great, right?

Uh, and I'm here looking at David and Tze-Woei, see if they disagree, because minor amputations, it's, it's just a terrible name.

Like, there's nothing minor about, you know, losing a toe or whatever, and I think a lot of times I see a lot of hurry.

When the patient, they're there, they're not septic, you know, they're gonna, they're gonna survive, just slow down, so I just, I don't know, this sounds like a slow down type case based on the, as I heard the case that Sara described.

So can I say something though?

Cause he, cause Tze-Woei did say something really cool and I was like, oh, I should mention this part.

And that was about amputating and then coming back for a revision.

Because one thing I think for our ID colleagues don't consider enough is the fact that you guys surgically need good tissue to flap.

And so if we can generate good, healthy tissue, get rid of infection there so that you guys can flap and have a more distal amputation.

That is a very legitimate use of antibiotics to get you guys the tissue that you need.

And also it speaks to this idea that Marcos had of slowing down, right?

If you needed to amputate higher and immediately close, um, that's different, right, than taking a measured approach where you might do a couple different stages with everyone on board together.

I, I'm, I'm with you.

I think the order of the day here is moderation, but I don't know if I would call it slowing down.

I would say be aggressively, surgically conservative in that.

You are, uh, marrying your antimicrobial therapy with rapid, aggressively tissue conservative debridement of the foot.

This is why, when we look at success or failure kind of over a large scale, we look at limb sparing procedures, like partial foot amputations or just incisions and drainage procedures of the foot over high level amputations like below knee and above knee amputations.

And so we actually use what we call a high to low amputation ratio just to get a little idea about the level of acuity of management of diabetic foot complications in a region or in a hospital.

And different hospitals can be very, very different, but that also shows you if you're talking about what Marcos was just talking about, which is that different clinicians can have dramatic impacts here where there might be a woman or a man that just says, you know what, Ms.

Garcia, she just has that problem.

She's going to get another one.

Let's just cut off her foot and be done with it.

And you know, for some patients, that's probably the best therapy, but I think most of us agree that the data are very strong, suggesting that's an extremely small number of patients.

And the great news is, nowadays, thanks to all you characters, we can reduce dramatically the rate of high level amputations to only a small fraction of all the ones that are done collectively in a unit.

Because usually, those things are not emergency procedures, they're almost semi elective in some cases.

Right?

I mean, not the one that Tze-Woei mentioned.

That's source control for someone that is where there is the life over limb issue, but for a lot of the other issues, when you just have the tissue loss now, and maybe some result in the infection, that is almost semi elective to where a person, she or he can make that decision with her or his clinicians and team around them and family.

Tze-Woei Tan: Yeah, I think I agree with Dr.

Armstrong.

I think team is the great approach or the right approach, right?

I think, uh, we don't take everyone with a severe infection to the OR.

In general, we talk to the podiatry or toe colleague to see whether there's any option for limb salvage and especially to drain the infection.

And we will try our best not to go for major amputation if possible.

Yeah.

So I tried to intentionally make this case a little bit challenging and sort of in the gray area.

So let's just say for this patient, they ended up being started on the classic vanc piptazo combo, you know, they rolled in through the ED, and so this patient does go for debridement of this ulcer and has some pretty significant necrosis and actually an abscess cavity that tracks to the head of that fifth metatarsal and through to the midfoot.

So he ultimately does require an amputation of his third, fourth, and fifth toe and needed a couple subsequent debridements to gain control of his infection.

From a vascular standpoint, he has an assessment completed after the infection is more under control and ultimately undergoes endovascular intervention for revascularization.

Um, so it has some balloon angioplasties of a couple stenoses.

His labs are improving from a white blood cell count standpoint.

His inflammatory markers are dropping and we have some bone cultures that are growing E.

coli.

I am going to open it back up to talk a little bit about clinical response in these patients.

What should we do with their antimicrobials now and any other thoughts that you may have on my, uh, made up case.

Well, I would made up ask you where, where were the cultures taken from, because I would just give a call out to Dr.

Armstrong and be like, Hey, is that the stuff that was going in the trash or was that a clean margin?

So let's say we don't know, or, or maybe I'll just throw it back and say, what if we talk through the what if of either scenario of if you had gotten information that it is from proximal or sort of, as you said, the stuff that goes in the trash.

So just one parenthesis there about inflammatory markers in particular.

I don't know about you guys, but I don't trend those at all.

For esr ESR, CRPs diabetic foot infections.

Like, I, I don't, I don't trend that.

I don't know if anybody does.

It's something that people get hung up a lot on, uh, just putting that out there.

Do you follow them, Megan, David, Tze-Woei?

I'm trying not to.

It's a hard habit to break.

I will say sometimes I think there's utility.

If we are in a scenario where we're using a PICC line, especially, not so much to worry about the infection down in the foot, but to catch.

like a line related complication.

So it's a different purpose.

I have found it's, it's, I know I should stop and it's so darn hard to, you know.

Yet another reason, um, Meghan, to pull that PICC line out.

That is amazing.

The only patient I have ever seen an ESR bump high, this is years ago when we were doing PICC lines all the time.

It's like, what the hell is this about?

Took the PICC line out, two days she came back with a line infection.

I'm like, ah, that was that ESR.

So glad I had it.

We make a lot of jokes in our unit.

We always say, we have a bone to PICC with you.

Uh, yeah, I think sometimes the first thing that someone wants to do is to throw a PICC in an arm and send someone out for six to eight weeks of, of antimicrobials.

And if they're a little sophisticated, maybe they're culture directed antimicrobials, but, but, we see this frequently.

We've been trying for a really long time to adhere to work that's done by, you know, many different clinicians, but one of my good friends here, about 500 yards in this direction from me is, uh, Brad Spellberg, uh, who will preach the mantra that, you know, shorter is better.

And if someone has a functioning gut, oral, um, is in many cases as good as IV and as long as you have coverage.

And I think there's times for both.

But we like to really adhere to that mantra, especially if we feel like we have a clean margin for this patient population.

I'll also say that I, I might follow a white count while someone's in hospital and we'll look if someone has a, you know, sky high SED rate or CRP, you know, so many of our patients are just pan inflammatory anyway, by the way, they're just, but, um, I won't follow the SED rate for trending, although it's kind of a nice idea,

you know, I might watch the white count drop, because even though half of our patients that we take to the operating room have a normal white count, you know, we published that back in the 90s, still, we might see a little drop in the white count, and maybe if we have an undulating white count or a persistently raising one,

maybe that means we did not get as good source control as we could, or maybe it means that there's another source, right, that we're missing collectively as a family.

Um, but, uh, so I might track that as we're thinking about, as rapidly as possible moving towards discharge.

I think you, you, you picked a really cool case, Sara, because there's all the uncertainties here, right?

So I think what you're trying to get us to talk about is, does this patient have residual cellulitis?

Does this patient have residual osteo?

Or nothing.

And this patient probably has residual cellulitis because you told us that they had cellulitis above the level of the ankle and we left their ankle there, right?

So odds are we need to treat some of that.

The issue of residual osteo is, I find one almost impossible to understand for the reasons that Meghan pointed out.

It's really hard to know what came from where.

Also, we don't really know what osteomyelitis is because the agreement between path and culture is a flip of a coin, and we don't know what it means prognostically to have residual positive margins by culture, path, or both.

We do have now that recommendation to do three weeks for residual osteomyelitis, and that is one recommendation that I really struggle with.

In part because it's based on a pilot trial of 92 patients with a non inferiority margin of 25 percent.

And I think something we don't talk a lot about is what's at risk here.

So is this somebody who is really not mobile and may have a little bit of osteo of the pinky and if that comes back I cut the pinky and we're good?

Or is this a 50 year old person who is working providing for their family, and if this thing comes back, we're talking BKA, right?

And, and I think that's what I take into account of how aggressive I want to, how much understanding I know nothing about this problem, right?

Cause I don't know what osteo is.

I don't know what residual margins mean.

I don't know anything.

So based on all that knowledge, what I do is based on some sort of risk assessment.

Wow.

What great discussions here, man.

I mean, the other thing is about, you know, we think that our buddies, That are down there, they're always down there in the basement of the hospital.

You know, you, it's either micro, both are basement people, uh, micro or a path, right?

You know, you go down there and you see them and they're like, struggle for the light.

And, you know, you, uh, and you walk down with, sometimes you walk down with a culture or path, and then they're so happy to see you.

It's like they haven't seen someone, it's like they've been, they've been isolated for so, so long.

And you go and you see them and uh, you pay 'em a little respect and then they're your best friend forever.

But I'll tell you what, we think that that is the final word, pathology, because it is the final word.

I mean, these guys are brilliant, but yet there is so much variability in, in assessment histologically for, for many things, for cancer and for bone infection.

Just as you said, Marcos, I think there was that paper this was like a few years ago where there's like 33 percent variability depending on different clinicians, uh, at teaching hospitals.

Right?

Uh, so it's, it, it really is wild.

Wow, so I think there's an element of subjectivity for all of us.

Speaking of that, could I ask a quick question to everyone else?

How do you all feel, Meghan, Marcus, specifically, about delivering a high level of antimicrobials locally, like through maybe, um, a polymethylmethacrylate or a calcium sulfate bead media for calcium phosphate.

So something that is absorbable on the calcium sulfate, phosphate bit or the non-absorbable on the, the string of pearls, kind of cement sort of thing.

What's the feeling in the infection?

I, I kind of know what the feeling, what's, what's the feeling in your, uh, community about, uh, about this and should I keep doing this or not?

And maybe how can I figure out whether this is really helping my patients or not.

For those who can't see, Marcos just shaking his head.

Meghan, I'll let you take that one.

It's like you see the bus coming and you're like, jump in front of it.

This is not fair.

Well, I would say, quite frankly, that I think that sort of topical antimicrobial, Dr.

Armstrong, is treating yourself more than the patient.

I don't think it's going to make or break the case.

It's also not the molehill that I'm willing to die on in terms of antimicrobial stewardship.

So, but I will also caution, you know, the, the thing that I have seen a few times become a problem are sometimes those, those antimicrobial beads tend to work themselves out the suture line and then everybody gets confused as to what they might be like, is that pus?

Are those gout crystals?

And so I think that is a potential, so, keep in mind as a, as a con.

What Megan said.

Great.

No, it's really an unknown, right?

And how do you study these things?

And being in a trauma center, we see a lot of the more classical use impregnated antibiotic nails, right?

I find that so fascinating because, like, are they good in the beginning, but do they eventually themselves become anitis for infection?

What grows biofilm, what doesn't?

We don't know the first thing.

And the other, uh, controversial is maybe not the best word, but discussed point about antimicrobials is whether or not we should add rifampin.

Who would like to

take a

stab at

that?

Does the patient have tuberculosis?

For those of you that don't know, Marcos Twitter handle is Limbs and Lungs.

So this is like the perfect tuberculosis sort of thing.

Well, I'm gonna wait for VA INTREPID to come out.

I think we are within a couple years of having a very solid, well informed data with which to answer your questions.

So, uh, I am politely going to pass for the next few years until that data is available.

Yeah, and I also 100 percent with Megan there, I think for those who read that retrospective paper.

A lot of the outcome difference there is not carried by limb salvage, it's carried by survival and patients who got rifampin were younger and less medications.

Which brings me to, oh my god, how much I wish VA INTREPID was testing rifabutin instead of rifampin, right, just because of the DDIs, which are, which can be a pain in the butt to manage.

But, well, I, Tze-Woei, I'm gonna put you on the spot here though, because let's play the future game.

What's going to happen if VA VA INTREPID says, Hey, we need to use rifampin, it improves outcomes as an adjuvant.

And you've got all these patients on Xa inhibitors that interact.

Is this something where we can think about potentially pausing them for the time of rifampin or is that risk benefit?

How do you see that risk benefit?

Tze-Woei Tan: I think those are for long term patency.

I don't think, uh, You know, we can always hold antiplatelet or anti Xa unless there's a reason.

If they are going on for PAD outcome, that's long term.

So I think there's no reason not to pause it and, uh, you know, continue the antibiotics if that is what the patient need.

I think it'd be different if patient is on anticoagulation for heart valve where you can't really stop them.

As we've talked about, you know, oversimplified a little bit with the case, just to give us something to have conversation.

But we focus significantly on antibiotics and then surgical management.

And I think an important message of your review is that there are a lot of other components of multidisciplinary, not necessarily diabetic foot infection, but diabetic foot care that we should be thinking about as either obviously preventative, but after the fact, you know, after they've been in the hospital and are on their way home.

And I was wondering if you could talk about some of those other components.

Is the patient gonna go home on the same shoe that they came in?

Perfect.

. David Armstrong: That, that was beautiful.

Perfect.

That's what I was looking for.

Marcos Schechter is an honorary podiatrist.

In fact, I will call you a PPE . You are.

The podiatry physician extender right there, man.

I just have to throw that.

So listen, that is great.

It is not what we put on these wounds that that heals them once we've sorted out the flow and once we've sorted out the infection.

It is what we, as you heard, is what we take off.

If we Uh, and this is a term for, for, for ID trainees, the term is called offloading.

Uh, it's not offloading the responsibility onto the, uh, onto something, it is offloading the pressure.

So you're spreading force out over a large unit area.

And this sounds like something that is super easy.

And FYI, it is so hard.

Why?

Because our patients are, right, why our patients may look like us and they may dress like us.

They are not going to act like us because they have lost what one of my mentors, Paul Brand, used to call the gift of pain.

And so they will behave differently because that hole in their foot You're having more of a reaction viscerally to that than they are, and they, just as Marcos said, may skip out of the hospital, leap out of the chair, leap out of the room, maybe Tze-Woei did a gorgeous endoheroic limb sparing procedure and there were all these other sorts of things happening and but then they leap out

and bound out of the hospital to the bus stop or to their car in the same shoes that caused the wound in the first place so this has to be protected but people don't focus on this very well.

Fewer than 2 percent of people get kind of the gold standard offloading therapy that they're supposed to get.

It's amazingly un golden, that gold standard.

That's why now we have an NIH sponsored study, this R01 that we're running now called the Smart Boot Study, where we're randomizing people into removable and irremovable boots, but also the boots that can maybe make up for some of that lack of pain, and give people some feedback, uh, of maybe a smart watch that can say, Hey, Mr.

Jones, great job, you're wearing your boot, or Hey, Ms.

Smith, that's not so hot, that boot's sitting next to your sofa, acting like a beer cozy, not acting like a, uh, offloading device.

So this sort of thing, doing things with our patients and not to them is really important.

So that's the offloading bit, um, that I think is really critically important.

Could I ask another ID tangential question, because I tend to be on one side of this argument, but I'm kind of becoming in between this argument that my friend, longtime friend, Ben Lipsky, I hope Ben listens to this podcast.

For those of you who don't know Ben Lipsky, please just, you guys, ID folks, Google him.

He's the ID hero.

Uh, and he's one of my longest standing friends in this area.

Ben was very much against giving people with a little bit of redness or something or stalled wounds, antibiotics.

That makes sense, obviously, doesn't it?

You don't want to give someone that doesn't have an infection antibiotics.

That's the, it goes against every tenet that one might believe in their training.

Another really good friend of mine, actually, I would say equally good, is a guy named Mike Edmonds.

This is another guy for you, uh, for everyone to Google.

Mike's at King's [College Hospital NHS], strategically several thousand miles away from Ben, who is in Washington state, um, and Mike Edmonds is a diabetologist.

And Mike often said, you know, sometimes these people kind of have something that's like sort of infected, but really not infected.

I'm going to give these people a little bit of antibiotics and see if it helps their wounds heal, even though I'm doing a good job of debriding and offloading them.

And he showed some of these patients would heal a little bit better.

I always felt like this was the most dumb idea in the universe, and I still feel that way, for sure.

I do not want to give non infected wounds antibiotics.

I'm going to say this, and it sounds heretical.

Maybe they're both right.

Uh, and maybe these wounds that are not infected clinically and classically, have some colonization that's inhibitory, um, and so some, last year I think we came up with a term that we called Chronic Inhibitory Bacterial Load, or CIBL, C I B L, kind of like chronic limb threatening ischemia, or or CLTI.

That patient population we think probably needs to be addressed in some fashion.

Maybe not with antibiotics, but maybe with just a really good quality debridement and serial assessments of load there, or maybe something clever locally.

I wonder what you guys think, because I think the data are emerging that some of these bacteria can inhibit healing,

even though they're not frank infections.

Just like you can have a glandular hyperplasia before you get a low grade prostate cancer, you know?

I think what you're getting at is like the role of the microbiome within the wound bed itself.

And so, I don't think that there is enough data for me to make clinical decisions yet, but I really hope that my microbiology colleagues start exploring this and start exploring this amazing communication that can happen between bacteria, between fungi, between human hosts, all within this milieu.

I think the tools are there to make these good studies possible, but we really have to back up and wait for the science to catch up to our eagerness to apply it.

Let me tell you, we have been working with whole genome shotgun and 16S, as you know, forever.

We called it from, I'll tell you how we're dating it.

We had a paper called from Louis Pasteur to CSI.

That's how long we've been doing this.

That's when CSI is now like Louis Pasteur.

So, so yes, but usually it's a paralysis of analysis, isn't it?

I'll tell you something that's fun that we're doing now, actually, is we're using kind of image based debridement where we're using basically blacklight.

No joke, like you'd see in a club, we're doing it on like feet, and we're imaging the porphyrin in bacteria, and we are then debriding the patients in our clinic, and my friend Stephanie Wolfel, who's a physical therapist, or if you're British, a physiotherapist, for those of you listening, she's doing some of this as well.

There, there are companies that make these devices both in a phone kind of form factor and then in a, uh, actually loupes on your, uh, like L O U P E S that you can put on your glasses so that's a fun thing that's giving you semi quantitative assessments.

I love your comments here.

I think it's a really rich area for inquiry.

I'm gonna quote two great foot people.

First, Ben himself, who is like, I think, the godfather of all ID doctors interested in feet, where he says, In diabetic foot ulcers, antibiotics are to cure the infection and not to heal the wound, which I think is a great saying.

And then there's this David guy, he wrote somewhere something like, We should be more worried about what we take off from wounds than what we put on them.

And when it comes to the bacteria, I would argue that, David, removing them is probably more important than any antibiotic I can sprinkle.

I'm glad he, that guy is here to confirm or deny that he said that.

Um,

, David Armstrong: I I can both, I I can definitely confirm that I said that.

I think I said that more than 20 years ago.

I idea.

I, I, I read it.

I read it.

At that time my dad used to read it to me.

Uh, but I think at that thing is fraying at the edges, man.

That thing on some wall.

A wall or on some hard drive somewhere.

But yes, that is true.

I think though that there are probably a lot of subtleties, uh, in this area now.

I think Graham Green said, life's not black and white, it's black and gray.

And I think there's just a lot of complexities in this area.

The more of this stuff you do, the more of those black and grays you start seeing.

But you are absolutely correct.

I think we need to debride and offload well.

And then we need to have, just like Meghan said, and you said, we need to have companion diagnostics and theranostics that are going to help us say, if this, then this, and we don't quite have that as well as we could yet, but it's getting better.

It's a fun time.

Like I said, to be doing this,

Sara, can I ask a, since we're just like, I don't even know that we're doing a podcast anymore.

We're just asking each other's questions.

I actually want to, I actually want to ask a question.

It's like, I think it might be useful for what you're getting to, but I've been more and more bothered by the follow up part of the patients?

Because just like nobody can diagnose an infection based on validated systems, are they getting better or worse?

That's even worse than the weathermen.

So I'm just curious, because at here, you know, we photograph the wound, we measure it, we put it on the chart, but at your institutions, what, how are you guys tracking wounds to see if people are progressing as they should, or, you know, any MR tricks, phones, like how are you guys keeping track of

Tze-Woei Tan: I think we, we follow them clinically.

I don't think we take any, other than pictures, and we want to make sure that they come back to see the surgeon who did the surgery, for sure.

And hopefully Dr.

Armstrong is not away giving some talk somewhere, and we have to cover his clinic.

But I think we follow them quickly, and as long as they're progressing and not getting worse, I think that's all we base on.

But by size alone?

Tze-Woei Tan: Size and the wound appearance, I think you know pretty fast.

It's not a subtle thing if, for example, if the stent goes down or bypass goes down, that's a big difference.

If, uh, they are not progressing, so like in a month they still look the same, uh, then something, so obviously I'm thinking more from the vascular perspective and you guys are thinking more from ID perspective.

Yeah, let me also add to that by indicating that actually in Tze-Woeis superb grand rounds that he just gave a couple hours ago, he talked about a friend of ours, Chris Lynch, who's a physician here in L.

A.

County and L.

A.

General Hospital, and he helps to run, uh, a program called Safer at Home.

Safer at Home started during, uh, the pandemic.

So it was very ID centric kind of start.

Um, but now it has evolved to where some of the most common patients treated are not upper respiratory or cardiopulmonary kind of things.

Um, it's actually diabetic foot, far and away the most common treated patients, and those patients are now getting a phone if they don't have a phone, um, or, but they're also getting nurses to visit them at home for assessments, and they're getting, uh, photographs.

We also have a program called the foot selfie program, where we have our patients send us photos, no joke, of their feet.

Um, I, I'm, I'm not kidding, when I was on this, I literally just got one right now from Chennai in India from a patient.

Um, that had come to visit us some weeks earlier . We then put all those into one set area, and then every Monday at seven, we have what we call foot selfie rounds.

And, you know, not a week goes by where we don't catch something and stop a hospitalization.

And that's done almost entirely manually.

What this grant is trying to do is to create kind of an AI based Sherpa to help improve that throughput.

Some of this is already happening thanks to, and no kidding, NVIDIA and the Diabetic Foot Grand Challenge, uh, Johnny Hancox in NVIDIA and Moi Hoon Yap in Manchester did this Foot Grand Challenge to identify wounds autonomously in under 10 seconds using a standard cell phone picture.

That's already published, that library is already online, but now we can take these data and use them and make them better and iterate them for our own place, whether that's at Grady, whether it's in Madison, or whether it's here in LA or all around the world.

So it's an exciting time because this stuff that is outside the hospital is, as you said, is way more important than what's inside the hospital.

Our goal is to maximize the Holy Trinity.

Ulcer free days.

Hospital free days.

Activity rich days.

And maybe antibiotic free days too, if you want to add a few.

Uh, well, you guys have been very, uh, kind to be on the podcast and spend a little bit of time asking each other and answering, uh, my questions.

I will just leave it open at the last section here to see if there's any point that you want to make before we wrap up.

Or, you know, a take home summary point just as closing thoughts.

Well, in the spirit of multidisciplinary, I want to make sure that we all emphasize each other's disciplines when we're talking to the patient, because it means a whole lot when I say, stay off your foot.

The patient knows it's not just coming from, you know, the podiatrist, um, and the same thing, you know, we didn't even get to touch on glycemic control at all, but as an ID doc or a podiatrist saying, hey, you know, lower your glucose, stop smoking, is re reinforcing the same message consistently is, is very important.

I, I think for the trainees who listen to this.

This is a very important disease.

It's much more nuanced and complicated than we learned during ID fellowship and internal medicine residency.

And there's so much of it in the U.

S.

and globally.

I think it's scientifically interesting and there is a big room to make a big impact.

And we don't think about it enough as a cool thing to do an ID.

It doesn't have the glamour it should.

Tze-Woei Tan: And I think we all get along.

Surgeon, non surgeon, ID doctor.

endocrine, toe and flow, glycemic control, primary care,

and metabolic jump.

Toe, flow and the metabolic know, and the ID know, K N O W, uh, listen, my dad used to say that, I can think of two great gifts at working at the end of the body, you know, my dad was a foot doctor too, and my daughter, Uh, is now going to be a third generation.

She's a PGY 1 in Texas now, UT, uh, but she's going to be a third generation foot doc.

Back in the day, I would say I could think of two great gifts at working at the end of the body, but the most important one is when you're, uh, looking after the foot.

Immediately, um, in this era of chest thumping, uh, and testosterone, you know, fueled kind of chatter.

I can't think of anything that's more of an expression of humility than looking after someone's feet.

And this is a humble little area.

It may be humble though, and I said little, but you know what, the trouble is it's not so little anymore.

This is a big area and it's interdisciplinary and, and with a little bit of humility and perspective.

Um, I think we can make a really, really big difference by just realizing it's not one individual.

No one is unto him or herself an island here.

When you put yourself together like you have here on this podcast amongst friends, I think we can affect big change, um, and we can eliminate preventable amputations over the next generation.

So listen, thanks for doing this and here's to that.

Oh, thank you guys.

And I have to say, this may be a record for most puns.

So I'll give you an extra congratulation for that.

A huge thank you to our guest stars today.

You can find their article, Evaluation and Management of Diabetes Related Foot Infections from CID linked in the episode info and in the Consult Notes.

We'll be back next week with another StAR episode.

Don't forget to check out the website, febrilepodcast.

com, where you can find the Consult Notes, our library of ID infographics, and a link to our merch store.

Febrile is produced with support from the Infectious Diseases Society of America, IDSA.

Please reach out if you have any suggestions for future shows or want to be more involved with Febrile.

Thanks for listening.

Stay safe, and I'll see you next time.