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Jessica: Hi guys. And welcome back to The Absite SmackDown! Podcast. This is your host, Jessica. And with me today is Dr. David Kashmer.
Dr. Kashmer: Hey Jessica. Good morning.
Jessica: Good morning, Dr. David. So I was listening to some of our past podcasts and my favorite, the five kind of silly or useless Absite facts and we talked about something, and it stood out to me and that was the Fothergill sign. And it made me wonder because it's something that we maybe don't use as much today because of CT scans and ultrasounds and just technology. What other facts or signs do we not use as much anymore? And so I was hoping you could talk about that.
Dr. Kashmer: There are so many of them, there are so many names signs. And when you told me you wanted to do this podcast, I looked back at some of the lists I have of these named surgical signs. You can also find some on the web and I'm going to tell you, there are so many! And I'll be straight with you, there are many I had never even heard of! It's really interesting. Before we get too into it, though. I want to tell you that back when I was a medical student and resident I wondered how good these signs are. Are they so useful as tests that you don't need all the fancy imaging studies? Or is it the reason we use such fancy imaging studies because these signs aren't so good. So I got really into this whole thing.
Jessica: So how did you test these theories? How did you figure it out?
Dr. Kashmer: Well, I can't say I figured everything out, but I can say that many of the signs that we're going to talk about have been studied and a lot of people use this thing called the kappa statistic. And I know this episode isn't about statistics, but the Kappa statistic is the inter-rater reliability of a sign or test or anything--meaning how likely two people are to agree on the presence or absence of something not owing the chance alone. In other words, not getting lucky, but really there being a difference there.
Jessica: Oh ok. Can you give us a scenario on that?
Dr. Kashmer: When I talk with medical students and sometimes surgeons and surgical residents about this on rounds, I have a really simple thought experiment. And here's how it goes: imagine there's a room with a hundred people, and I'm going to tell you in this room, there are 50 people who have a certain type of heart finding called an S3.
Okay. And, what we're going to do is I'm going to give the resident a stethoscope and say, go in that room and listen to everybody and come on out and tell me how many people have this finding. So they're really good. They go in, they listen, they come out, they say, “Dave, there are 50 people in that room who have this finding.” And I say, okay, well, let me go in. I may not be as good with a stethoscope anymore. And, I go in there and I listened and I say, “Yeah, 50.”
So if you look at the face of it, Jessica, we both agree that out of this one hundred people 50 have this finding. So it looks like we completely agree on the face of it. But what the Kappa statistic does is it shows us how many of those people are the same 50 people. What's the overlap in the group that they have versus the group that I have? It turns out many of the signs we are going to talk about have a low kappa statistic—so that means they aren’t useful.
Jessica: Okay. So which signs have good ones and which ones don't?
Dr. Kashmer: Well, it turns out that many of the physical exam findings in the cardiac exam do not have a lot of utility. In other words, a lot of the things we listen for on a heart exam when we're talking to residents, those don't, or when we're teaching medical students, those do not have a lot of utility.
I used the S3 in our little example. I used that because that's actually a very good one in terms of physical signs for the kappa statistic. Presence of an S3 is associated with heart failure. So that's one...and we're pretty far away from Surgery here (!)
Jessica: Okay. So what do you feel, or from your studies, what signs did you think are the most useful?
Dr. Kashmer: Well, first let's talk about a lot of the ones we hear about. They all have a really cool historic--there's a story behind each of these signs. So for example, Chvostek sign, and Trousseau sign are two associated with hypocalcemia--low serum calcium. And the story of these as it was told to me, and you know, these stories are never, perfect. These little things we get on rounds…it’s always more complex than what we were told.
Jessica: Like a game of telephone: how it starts at one, and by the time it gets around, it's a different story.
Dr. Kashmer: It is. And I saw this particular one later on after I was told about it on rounds. I saw it in a book called A History Of Surgery, but you never know, you never know what it really was, but here's how it goes…Chvostek and Trousseau’s are associated with low serum calcium. For Chvostek’s, you tap over the nerve at the tragus and the facial muscles twitch. Trousseau’s is inflation of a blood pressure cuff on the arm. And it makes this what's called carpo-pedal spasm. These are both associated with low serum calcium--hypocalcemia. It turns out that they're also associated with a low serum magnesium, hypomagnesemia, as well which is not as commonly known, but gets tested. It's interesting. What was on my Absite for these is a Chvostek sign and Trousseau sign and somehow hypomagnesemia, and it's just not typically how we think about it, but it's because of the cotransport effect and other effects of magnesium on calcium.
And what else is kind of interesting about it is the story associated with these it goes like this: it turns out that Bilroth, a European surgeon, who's known for the Bilroth one and two procedures (which are talked about all the time as we teach surgery for ulcer disease and other things)…these are kind of foregut procedures that he came up with. Bilroth also used to take out thyroid and we all use this clamp called a Kocher clamp. Theodore Kocher was sort of an apprentice or worked with Bilroth. And Kocher this clamp that has these teeth on the end. And it's kind of a long clamp. It's like almost a straight Kelly clamp for the residents and staff listening.
And this clamp with these teeth on the end was actually used for thyroid surgery, which nowadays we really wouldn't think of it really for thyroid surgery, but that's what he used it for. And what happened was Bilroth would take out the thyroid from these patients for different reasons. And then some of them would have tetany these horrible muscle contractions, where they would just tense up. You get like this profound cramping and you can't move. And it's terrible, not many. And Theodore Kocher kind of looked at what Bilroth was doing and kind of looked at the thyroids that came out and said, what are these like yellow, these kind of yellow, fatty things. Well, it turns out those were the parathyroid that we didn't really know existed. And those secrete parathyroid hormone and Bilroth was taking him out. I mean, we didn't really know they were there.
And, sometimes they do come out when you take thyroid out, it's possible. They can be in the substance of the thyroid and all this other stuff, but you don't usually take out all four with modern technique with how we do it. It's pretty unusual. So Chvostek and Trousseau’s were the signs associated with this hypocalcemia. And the reason why is parathyroid hormone antagonizes, another hormone called calcitonin. Calcitonin moves calcium into the bones and parathyroid hormone antagonizes tha--it brings calcium out. So, the removal of the thyroid takes out parathyroid hormone. Patients could have anything from hypercalcemia transiently, (which is pretty unusual) to more typically hypocalcemia.
So all these signs are like wrapped up in these historic, you know, these famous stories and all this interesting stuff. That wasn't how those signs were discovered, but that's part of how they relate to us in Surgery. And each of these crazy signs that we're going to mention have something like that. So bottom line is many are wrapped up in this history of the appendix and the history of thyroid surgery, et cetera. But nowadays we only rarely use them in management.
Jessica: What do you think? Which sign do you think has the coolest story that goes along with that?
Dr. Kashmer: Well, I already tipped my hand with the story about Kocher. But I'll tell you, you asked me the one that sent me off: “Which ones are useful and which ones aren't?” and around the appendix, some of the ones we still teach routinely that are used routinely include McBurney's point tenderness. McBurney's point tenderness occurs in the location called McBurney's point which is found along a line drawn from the umbilicus toward the right lower quadrant and toward the anterior superior iliac spine. About two thirds of the way down there is the spot. And if you have tenderness at McBurney's point, sometime particularly worse when you let go, that is classic for appendicitis. Then there’s Rovsing’s sign. And psoas sign, with manipulating the leg. and those are ones we still routinely teach.
And many people asserted when I was training: you really don't need a CT scan to diagnose appendicitis, but even with all those great signs and a story that fits and a high what's called pretest probability of appendicitis, every once in a while, you'd find another diagnosis in there, like a Meckel's diverticulum or something else. And nowadays, and surgeons were even shaking their head at this when I was, and, and sometimes in the literature still shake their head at this. When I was a resident, many people get CT scans in the ER. As they come through, you almost can't stop it. So the classic appendicitis in the classic age group has a lot of physical exam findings that we still teach, but they don't work well for older patients with appendicitis who are functionally immunosuppressed or morbidly obese patients, which we're seeing more and more, in many age groups. So, you know, the coolest story I think is Chvostek and Trousseau’s, and ones you see used most include McBurney's point tenderness and like a Rovsing’s. But even those are not always great.
Jessica: I think it's funny. I never knew the name for that, but I remember just as a young child, if you went in for stomach pain at the, at school, the nurse would press down there and when she'd let go she would ask you “does it hurt more when I press down or let go?” And I never realized what she was doing until this moment, as you explained it. That was a sign that maybe she was looking for.
Dr. Kashmer: It turns out that even sometimes when you push in the right lower quadrant and you let go and it's worse and they have this subtle peritoneal inflammation, even then, it's not really, it's not appendicitis, but in the age group that, you know, 20 year old male or something like that, it's a lot more likely to be appendicitis than many other things. So that's kind of why these work. It’s really interesting, you know, when you're teaching first year residents and then later year residents, or the first year resident goes in and pushes on the patient's belly, the junior resident feels the patient definitely have right lower quadrant tenderness. And then they leave the room. They tell their senior resident. Senior resident comes in and pushes on and says, no, that's not right lower quadrant tenderness. You know, your nail just dug into and, or you did something else.
Every time I saw that, and you see that a bunch, that's a Kappa statistic phenomenon. Two people disagreeing on a sign being present or absent. More powerful tests are ones that make it such that you look at that and you go, “Oh, there's a clear difference.” I can see it from across the room. Do you understand what I mean by that?
Jessica: Yes. All right. Well, again, it's always a pleasure to have you in the studio. And this is a really interesting topic on, you know, different signs and backstories. And I love when we can just have those kinds of conversations and learn something new. So thanks for coming in today.
Dr. Kashmer: Thanks so much. And as we part ways, I just want to share with everybody, you know, we talked about a couple interesting signs, maybe four or five, but there are so many. Like Howship-Romberg sign for obdurator hernia. Sometimes the sign is all you have to get a clue about a difficult diagnosis. And you know, when you and I were talking about this podcast, we were deciding, do we go through each sign or how many stories do we tell or what do we do? So before everybody goes, I want to give them some of the other resources for signs.
Wikipedia actually is kind of fun and entertaining for this. Okay. but there are lots of resources online. If you do a Google search for a surgical signs, lots of stuff will come up. There's a website, medchrome.com/major/surgery/important-signs-surgery. That'll bring up a list, which is one of the best ones.
There are many prominent ones that are used clinically that we didn't talk about, like raccoon eyes and Battle’s sign. These signs you see in trauma that are actually really useful for different diagnoses, like basilar skull fracture. So don't take the message from this that all these physical signs are historic interest only, and not too useful.
Sometimes if you're in a rush, you don't have time to get the big fancy test. And to learn more about it, if you have a personal interest, a there's something called the odds ratio, which talks about the odds on someone having a disease when they have a finding with a finding versus the odds when somebody's having a disease when they don't. And there's just so much to this that I think really helps with decision making. I think this is sort of a pathway to teaching surgical residents good decision making. How powerful are these signs? Where do they fit in your decision making? And when should they change your mind for what diagnosis a patient has or how you should act? So I just wanted to close with that. I really appreciate the time today. So many cool stories around these physical signs.
Jessica: Well, like you said, you gave the links and the listeners can look more for themselves. You want more information? Maybe we’ll write a blog on it! I don't know. But again, thanks for coming in. And everybody, please remember #AbsiteSmackdown!