Name:
ABSITE Review: Hepatobiliary Part 1
Description:
ABSITE Review: Hepatobiliary Part 1
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/06c20ad4-f370-4e66-bb48-dc96af6907e9/thumbnails/06c20ad4-f370-4e66-bb48-dc96af6907e9.jpg?sv=2019-02-02&sr=c&sig=YsfnaSonKJV5B9bMaTnPXzXtExua35FuvzHfoxW8UNU%3D&st=2024-05-03T10%3A56%3A17Z&se=2024-05-03T15%3A01%3A17Z&sp=r
Duration:
T00H33M33S
Embed URL:
https://stream.cadmore.media/player/06c20ad4-f370-4e66-bb48-dc96af6907e9
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/06c20ad4-f370-4e66-bb48-dc96af6907e9/Behind20The20Knife-20ABSITE20Review-20Hepatobiliary20Part201.mp3?sv=2019-02-02&sr=c&sig=QbkRR3WgeJ2x%2BmpIKyTmTH%2Fjk3q%2FIBjPjLdfv%2Fgw4%2FA%3D&st=2024-05-03T10%3A56%3A17Z&se=2024-05-03T13%3A01%3A17Z&sp=r
Upload Date:
2022-02-28T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[Dr. Kashyap] Welcome back to Behind the Knife's ABSITE review. This is Meghana here, we really appreciate your support over the years, we're coming up on 6 million downloads from over 80 different countries. Thank you for supporting the podcast and taking it to the next level. Continue to follow us on Facebook, find us on Twitter, subscribe to the podcast, leave reviews, and also go to our YouTube channel and subscribe to that.
As it is ABSITE season, we're pleased to offer you this content and don't forget to follow along with the companion book that we're providing this year. It's available on Amazon, search for 'Behind the Knife'. It's a Kindle ebook that you can download immediately, and it's $10 with all proceeds going towards improving our educational content. For the high-yield review sheets and stat sheet, it's available on our Facebook page, so follow us there.
Dominate the ABSITE this year and let's get into it.
DR. BINGHAM: Okay, let's get started. I hope everybody's ABSITE studying is going well so far. So Hepatobiliary Part 1. Hepatobiliary is a big subject, so we broke it up in two segments. Let's jump right into it with some high-yield anatomy. So Woo, what makes up the portal triad?
DR. DO: So the portal triad contains the common bile duct, the proper hepatic artery, and the portal vein. This runs in the hepatoduodenal ligament.
DR. BINGHAM: Yep, and so the proper hepatic artery, not the common. CBD, proper hepatic artery, portal vein, hepatoduodenal ligament. Kevin, what separates the left and the right lobe of the liver?
DR. KNIERY: The right and the left lobe of liver is separated by Cantlie's line, it's the line between-- if you drew a line between the gallbladder fossa and the inferior vena cava.
DR. BINGHAM: And not the falciform. They'll try and trick you, it's not the falciform. It's Cantlie's line, separates right and left lobes of the liver.
DR. KNIERY: One thing I just wanted to point out on the portal triad, is there is anatomy questions that ask their relationship to each other. And so it's important to remember that the artery is medial to the bile duct and the portal vein is posterior to both of those.
DR. BINGHAM: Perfect, yep, they do like to ask that, and it's important to know clinically as well. So it's going to be a little bit difficult over an audio format but Woo, can you walk us through a visual tour of the liver, with all these segments that often come up, that you have to kind of know where they're positioned. What's a good way of thinking about that?
DR. DO: Yeah, so again, it's easiest to look at an illustration as you look through this, but think of the caudate lobe, it's that separate segment, it's segment 1, and then break apart the left side and the right side. So on the left side, there's 2 and 3, and those are the left lateral segments. And there's 4, there's a 4a and 4b, and those are the left inferior anteromedial segments. Then on your right side, you have 5, 6, 7, 8.
DR. DO: And so the 5 is the right inferior anteromedial, the 6 and 7 are the right posterolateral segments, and the 8 is the right superior anteromedial.
DR. KNIERY: One thing I think we'll go over later is they'll ask you a right hepatectomy, what segments are removed in that versus a left or an extended right. And so those are how those become clinically relevant on the ABSITE.
DR. BINGHAM: And they also like to ask, I'd like to throw in there, they'll give you a patient who has a metastatic tumor and they'll tell you what segments, so you have to know if that's a left lateral segment or that's one of the deeper segments, and that helps guide your therapy as to how you're going to approach treating that or performing a metastasectomy. So it's definitely a favorite, you really need to know it.
DR. BINGHAM: Like Woo said, the best way to do it is open up an anatomy textbook and just have that image in your head and know where the segments of the liver are. So how about the hepatic veins, Kevin? Tell me about those, where do they drain, how many are there?
DR. KNIERY: Right, so you have three hepatic veins. They drain directly from the liver into the inferior vena cava. So you generally have the right, which drains directly into the inferior vena cava itself. And then the left and medial hepatic vein join together and form a confluence, and then plug into the inferior vena cava.
DR. BINGHAM: Okay, great. There's a lot of aberrant vascular anatomy that's important to know. There's your replaced right hepatic, and there's your replaced left hepatic. So Woo, where do those originate and where do they run?
DR. DO: Yeah, so the replaced right hepatic most commonly comes off the SMA, it travels behind the pancreas and the common bile duct. This is in contrast to the replaced left hepatic, which comes off the left gastric artery, travels in the gastrohepatic ligament.
DR. BINGHAM: That's a favorite one to ask, they'll either straight up tell you that a patient has a replaced right or left hepatic and they'll ask you what the origin is. So the replaced right off the SMA, and the replaced left off the left gastric. That is especially important when you're doing foregut surgery and you're opening up the gastrohepatic ligament, that you don't ligate that or you don't run into that. Okay, moving on to some clinically relevant stuff, let's start off with some basics.
DR. BINGHAM: This is probably something most people out there are pretty familiar with, which is benign biliary disease. That being said, we're not going to go over the basics of clinical presentation of gallstone disease, as, like I said, by this point, it should be pretty much second nature to most people, but we'll move through this real quick. So Woo, how do you want to handle somebody who presents with asymptomatic cholelithiasis?
DR. DO: So these patients, you just start with observation.
DR. BINGHAM: Okay, how about somebody who has uncomplicated symptomatic cholelithiasis?
DR. DO: Elective cholecystectomy.
DR. BINGHAM: Somebody gets a little bit trickier is what if your patient's pregnant? So how do you want to manage symptomatic cholelithiasis in a pregnant patient?
DR. DO: So here, you have to bear in mind that there are higher rates of spontaneous abortion with non-operative management. So ideally, these patients should undergo laparoscopic cholecystectomy, generally in the second trimester. You would place supports via an open Hasson technique, and keep the pneumoperitoneum as low as possible. Also, try to place a bump under the right side to offload the vena cava.
DR. BINGHAM: Yeah, I think they used to try and push patients and get them through their pregnancy before taking their gallbladder out, but the most recent stages of guidance is to go ahead and perform your elective cholecystectomy even if the patient is pregnant, with those precautions, as you stated. Okay, Kevin, how about acute cholecystitis? When do you want to time that operation?
DR. KNIERY: So for acute cholecystitis, there's no benefit to cooling off the patient. So generally they should be in an urgent setting, taken to the operating room for surgery. So if they come in the middle of the night, the next morning, they should go to the operating room.
DR. BINGHAM: Yep, so early cholecystectomy is the way to go with acute cholecystitis in a surgically fit patient. Now, what if they give you a patient that's just a disaster, that's just a completely surgically unfit patient. What's the answer then?
DR. KNIERY: Right, if it truly is that bad, and they would not tolerate a laparoscopic cholecystectomy, you can consider a cholecystostomy tube.
DR. BINGHAM: Okay, and how about once that patient recovers, then what do you do?
DR. KNIERY: Then they should be playing for an elective cholesystectomy.
DR. BINGHAM: Right, a cholecystostomy is not definitive treatment, but it is a temporizing measure. Okay, so that's cholecystitis, that's cholelithiasis. How about choledocholithiasis? This can be a little bit more difficult, a little bit more tricky. So, Woo, what's your approach to the management of a patient with suspected choledocholithiasis?
DR. DO: Yeah, so there are several accepted approaches and there's a lot of variability between institutions, but in general, if you have a really strong suspicion, so say, the common bile duct stone is seen on imaging, or there is clinical evidence of cholangitis, or bilirubin of greater than three, or a dilated CBD of greater than six millimeters, you should consider pre-operative ERCP for clearance of the duct. You could also do IOC intraoperatively, and also consider a common bile duct exploration if ERCP is not available.
DR. BINGHAM: Okay, so that's your patient who comes in, and you, based on their imaging, based on their labs, you're like, "This patient has a stone in their duct." What about those ones where maybe they have a few abnormal liver tests, they have a mild elevation of the bilirubin or gallstone pancreatitis. What do you want to do with that patient?
DR. DO: So here both MRCP and just a laparoscopic cholecystectomy with intraoperative cholangiogram would be acceptable answers.
DR. BINGHAM: Yeah, I think the key there is you have a moderate suspicion for a stone in the duct, so you need to do something to image that whether that's a pre-operative MRCP or that's an intraoperative, an IOC. Maybe you don't have enough suspicion to go ahead with the pre-operative ERCP, but you definitely want to image the duct. Okay, what about an easy one, the low suspicion. Their labs are normal and they have nothing on imaging to suggest a common bile duct stone.
DR. DO: Here you really don't need any further investigation prior to the cholecystectomy.
DR. BINGHAM: Right, and some people will do routine IOCs in everybody, and that's fine but that's certainly not required and you don't feel obligated to do that in a Board scenario either. Okay, so let's say you had a patient who had a moderate suspicion, you take them to the OR, you do your lap chole, you do an IOC and you identify a common bile duct stone during your cholangiogram. What are your next steps?
DR. DO: So first, during the intraoperative cholangiogram, once the stone is identified, you should try to flush the stone through, and using glucagon if the stone has difficulty flushing alone could be very helpful.
DR. BINGHAM: Okay, those are your first steps, those are going to be your answers for the first steps is glucagon, you can give that up to twice, and you flush with normal saline. But let's say that doesn't work, and let's say you'll have a small stone and you have a pretty sizeable cystic duct. What's your approach then?
DR. DO: Yeah, so here the key is that the stone is small and the cystic duct appears large. So if that were the case, you should try a transcystic common bile duct exploration using fluoroscopic guidance or you could use a choledochoscope.
DR. BINGHAM: Okay, and how about if you have a tiny little cystic duct and you have a large stone, and you just don't think you're going to be able to get there with a transcystic approach?
DR. DO: Here the preferred approach is either a laparoscopic common bile duct exploration, or if you don't feel confident in that, then you could do a post-operative ERCP, and all this depends on the resources available to you and the surgeon experience.
DR. BINGHAM: Yeah, I think you'll see, managing these patients, there's a lot of variability in practice and there's a lot of acceptable approaches. So you just kind of have to know the options available. You have to know that if you have ERCP available, that's okay, if you don't and you have surgeon experience, you can do either a laparoscopic or open common bile duct exploration. So the key there is just knowing all the available options and know that there's a lot of acceptable ways of going about that.
DR. BINGHAM: Okay, Woo, let's say you're doing your cholangiogram and you don't get any filling proximally of your hepatic ducts, you don't visualize your hepatic ducts. What are your next steps?
DR. DO: You could try to pull the catheter back a little bit prior to flushing again and re-shooting the cholangiogram. And you can also try to place a patient in Trendelenburg to see if there's any change in the imaging.
DR. BINGHAM: Okay, what if you do that- I agree, you try those simple things first, you re-position your catheter, maybe you put it in too far. You use gravity to your advantage so you put the head down, see if you can get some backfilling into those hepatic ducts but what if you do that and still you see a cutoff, where you don't visualize one of your hepatic ducts, what are you really worried about, what do you got to do then?
DR. DO: At that point, you would have to convert to an open procedure and investigate and see if there is an injury to the hepatic duct.
DR. BINGHAM: Right and that's going to be the answer. You have a high suspicion that you've ligated or you've injured a hepatic duct, so you have to open to divine your anatomy. Okay, moving on, Kevin. Gallstone pancreatitis, what's your approach?
DR. KNIERY: So for gallstone pancreatitis, they will, at some point in the near future, need a cholecystectomy, but you generally do not do it at their initial presentation.
DR. BINGHAM: Let's start with-- they present with gallstone pancreatitis. Do those patients need an ERCP to clear the duct?
DR. KNIERY: If there is evidence of choledocholithiasis or active cholangitis, then yes, they would need an ERCP, but if there's just pancreatitis, there's no role for ERCP.
DR. BINGHAM: Yeah, so just your run of the mill patient who presents with pancreatitis and you suspect has gallstone pancreatitis, unless they have one of those other indications that you strongly suspect that there's a big stone lodged in the duct or they have evidence of cholangitis, most of those stones will pass, and they don't necessarily need an ERCP. So you initially manage them medically to cool off their pancreatitis, but how do you want to time their cholecystectomy?
DR. KNIERY: It's generally recommended, and I think the ABSITE answer will be during that same hospitalization.
DR. BINGHAM: Exactly, so there's a very high recurrence rate and they can have serious sequela. I think it's upwards of 40% at 30 days, somebody might have to double-check me, but I think that's the number. So the recommendation is cholecystectomy during that hospitalization, so before that patient goes home. So that's going to be the answer on the ABSITE. How about, you have severe pancreatitis, and on your imaging you see a large peripancreatic fluid collection?
DR. BINGHAM: What about the timing of cholecystectomy in those patients?
DR. KNIERY: So in these patients, they're generally very ill and their abdomen is not suitable for surgery due to the intense inflammatory reaction. So in these patients, this is the one case that doing an interval cholecystectomy at six to eight weeks is probably preferred. And they recommend doing an ERCP or sphincterotomy to reduce the risk of complications during this waiting period.
DR. BINGHAM: Yeah, that's the caveat there. With those patients, they need to cool off a little bit, but you have to do something to reduce that risk of early recurrence, so they need an ERCP with a sphincterotomy. Okay, Woo, another favorite that's highly testable, rarely seen, is gallstone ileus. What do I mean when I say gallstone ileus?
DR. DO: So this is actually not a true ileus, but rather a small bowel obstruction, and the obstruction is caused by a gallstone that is typically lodged at the IC valve. This generally results from a cholecystoenteric fistula, and it's usually a fistula to the duodenum.
DR. BINGHAM: There's a triad, I think, that's associated with it, a triad of symptoms, what is that?
DR. DO: Yeah, that's called the Rigler's triad, R-I-G-L-E-R, and that consists of a bowel obstruction, a gallstone seen in the intestine on plain film imaging, and pneumobilia as well on imaging.
DR. BINGHAM: And this is going to be another one where they're going to show you an X-ray. They're going to show you an X-ray with a bowel obstruction, you got to look down to the right lower quadrant, they'll give you a visible gallstone on the X-ray, and they'll give you air in the biliary tree, and they'll ask you what to do. So if you get that question, you get that picture, Woo, what are you going to do?
DR. DO: So the primary goal is to relieve the obstruction. And so you're going to perform an enterotomy proximal to the obstruction and milk the stone back, and remove it through that enterotomy.
DR. BINGHAM: Okay, and then what would you do with the gallbladder?
DR. DO: So this is a little bit controversial regarding the cholecystectomy and takedown of the fistula at the time of the enterolithotomy. In general, I would not do this. The combined procedure has a higher morbidity, and recurrence rates are low in general. You can consider doing this in select circumstances, such as with a very stable patient or in a patient with gangrenous cholecystitis. So in other words, they really need to be stable or really, really need their gallbladder out.
DR. DO: Otherwise, I would just focus on relieving the obstruction and getting out.
DR. BINGHAM: Yeah, and that's the way they're going to do it, they're going to give you that image, and they're going to give you options. They're going to say, perform a lysis of adhesions, they're going to say, perform a bowel resection, they're going to say, make an enterotomy, milk the stone back, and close your enterotomy. They're going to say, do that, and then perform the cholecystectomy. The answer is going to be make your enterotomy and get the stone out, relieve the obstruction and get out.
DR. BINGHAM: Unless it's some other extenuating circumstances, but 99% that's going to be the question that you're going to get. Okay, Kevin, let's move on to gallbladder polyps. They're pretty common, they're a lot of times incidentally seen during cholecystectomy, lots of times incidentally found on imaging. What are gallbladder polyps and how do you manage them?
DR. KNIERY: So the majority of them are benign hyperplastic polyps and if they are symptomatic, that would be an indication for a cholecystectomy, but if they're asymptomatic like the majority of them will be, it'll just be found on routine imaging, you don't need to do anything about them, unless they get bigger than 10 millimeters in size and that's when we get worried about adenoma to carcinoma kind of sequence. So if they're greater than 10 millimeters in size, they should also have a cholecystectomy.
DR. BINGHAM: Yep, so that's a good cutoff, 10 millimeters in size is considered an increased risk of it being an incidental cancer, so still very low, but still, the risk is there, so they recommend cholecystectomy. Very, very large ones, so larger than, the number is 18 millimeters, if they're larger than 18 millimeters, you treat it as gallbladder cancer until proven otherwise. And then polyps over six millimeters will need some form of serial imaging, so serial ultrasounds.
DR. BINGHAM: If the patient simply doesn't want to do that, it's okay to go ahead and do a cholecystectomy for those smaller polyps, just to avoid the need for surveillance. But again, symptomatic, cholecystectomy. Asymptomatic and small, leave alone. Asymptomatic over six millimeters, either serial image or do a cholecystectomy. Asymptomatic, over a centimeter or 10 millimeters, cholecystectomy.
DR. BINGHAM: And over 18 millimeters, treat it like it's cancer. Okay, moving on. Let's talk a little bit about portal hypertension. This is difficult to often conceptualize, but they like asking questions about these things on the Board. So Woo, what actually defines portal hypertension?
DR. DO: So this is actually defined as a hepatic vein pressure gradient, HVPG, greater than 6 mmHg.
DR. BINGHAM: Okay, back up, hepatic vein pressure gradient. What is that, what do you mean by that?
DR. DO: Yeah, so this is the gradient between the wedged hepatic vein pressure and the free hepatic vein pressure. So to measure it, you actually require the passage of a balloon catheter into the hepatic vein under fluoroscopy.
DR. BINGHAM: Right, so if you have increased portal hypertension this will result in portosystemic venous collaterals, ascites, hepatic encephalopathy, splenomegaly, all those kinds of sequela. We know it's associated with cirrhosis and portal hypertension. So there's a lot of different causes, and the actual site of the increased portal resistance depends on the etiology of the portal hypertension. So a lot of times you'll see pre-sinusoidal, sinusoidal, post-sinusoidal, Woo, break that down for us.
DR. BINGHAM: How does that translate?
DR. DO: Yeah, so the easiest way to break down portal hypertension, as Jason mentioned, is into these three categories. Is it before the sinusoids, at the sinusoids, or after the sinusoids? So a pre-sinusoidal etiology would be something like schistosomiasis, something at the sinusoids would be alcoholic cirrhosis or viral hepatitis, and beyond the sinusoids, you could have Budd-Chiari syndrome.
DR. BINGHAM: Yep, that's a good way of breaking it up. It is somewhat of an over-simplification, as a lot of disorders will cause increased pressure at several different locations, like primary biliary cirrhosis is a good example, it has both pre-sinusoidal and sinusoidal elements. But yeah, that's a good way of thinking about it. And sometimes you will be asked where's the site, what kind of portal hypertension is this? So Kevin, how about some of those- some of that collateral circulation we were talking about?
DR. BINGHAM: Where do people form collaterals if they have portal hypertension?
DR. KNIERY: Right, so this is where the splanchnic venous system meets with the systemic drainage. And when you have portal hypertension your splanchnic system is overwhelmed and high-pressure, so it's going to preferentially drain into some of the systemic drainage sites that have lower pressure. So one of the more common ones we think of is the distal esophagus, as you get esophageal varices, and that's what this is. And then you also see those in the proximal stomach.
DR. KNIERY: You can also see this in the rectum. This is from the inferior mesenteric vein, which is your splanchnic draining into the systemic, which is the pudendal vein, so you'll get rectal varices there. And then you'll also see classically in the textbooks, you'll see the umbilicus. And this is from your umbilical vein, your vestigial umbilical vein recanalizes to the left portal vein, and so your umbilicus will have varices around that.
DR. KNIERY: And then you also see them in the retroperitoneum, with the mesenteric draining into the ovarian veins.
DR. BINGHAM: Okay, so this is one of those things where medical treatment is the first line for portal hypertension. So Woo, what are some of those pharmacologic treatments that patients with portal hypertension get put on?
DR. DO: Yeah, so for medical therapy in the acute setting, you want to think about splanchnic vasoconstrictors, so vasopressin or octreotide. Additionally, non-selective beta blockers can be very helpful for prophylaxis, and these comprise nadolol or propranolol.
DR. BINGHAM: Yeah, and then you have some of the other treatments like endoscopic variceal banding for your esophageal varices. How about TIPS, Kevin? What's TIPS and when do you want to use that?
DR. KNIERY: Yes, this will definitely be a question on the ABSITE. So this is the patient that has acute or recurrent variceal bleeding, refractory ascites, Budd-Chiari syndrome, or hepatic hydrothorax. And the whole point of this is to decompress the portal system, and this is done through an endoscopic fluoroscopic method.
DR. BINGHAM: Okay, Woo, so let's move on to a patient who has esophageal varices and has an acute esophageal variceal bleed. What's your management of that patient? How are you going to approach that?
DR. DO: So for this patient, you want to start with your standard measures of resuscitation, transfuse if necessary, start broad spectrum antibiotics, intubate the patient for airway protection, start octreotide, and then you want to move quickly towards endoscopic treatment. If the patient has uncontrolled bleeding even with endoscopy, then I would move towards a TIPS.
DR. BINGHAM: If you're going to do that, though, they're bleeding, and you need to take them for TIPS. What do you have to do? What do you need to temporize them with?
DR. DO: Yeah, so the temporizing measure here would be balloon tamponade.
DR. BINGHAM: Yeah, so like your Blakemore balloon, all those things. It's a very scary situation if you ever have to do that. So let's say that you get initial endoscopic control of the bleed, you do all those things, you resuscitate, you type and cross, you transfuse, you start antibiotics, they're intubated, you start an octreotide drip, you do your endoscopy, you get a little control, and then a couple of hours later, they bleed again.
DR. BINGHAM: What do you want to do then?
DR. DO: So here the patient has had initial endoscopic control and has re-bled, then I would go for a second attempt at endoscopy.
DR. BINGHAM: Yeah. It's not that dissimilar to other upper GI bleeding, a second endoscopy would be the answer. But then, they need their TIPS. So either you get control endoscopically or you do your Blakemore balloon, but they need TIPS.
DR. KNIERY: And one quick thing on TIPS, so it is a transjugular intrahepatic portosystemic shunt. And so through the internal jugular vein, the interventional radiologists canulate the hepatic vein and basically make a stent between the hepatic vein and the portal vein, which allows the portal venous pressure, which is high, to drain into the hepatic veins, and then into the systemic circulation in the IVC, and this is how you get control and reduce the portal pressure.
DR. KNIERY: And a lot of times when patients have had these in the past and they come in with recurrent bleeding six months later, you want to start with an ultrasound of the TIPS to make sure that the stent still has flow through it and is draining from the portal system into the systemic venous system.
DR. BINGHAM: Yeah, it's one of those things that it just blows my mind that it works, and somebody had a lot of guts to try that for the first time, I think. I don't know who figured that out. So we see a lot less surgery for portal hypertension since the advent of TIPS, but let's briefly go through some of those surgeries. So Woo, what are some of your different surgical options for portal hypertension?
DR. DO: Yeah, and again, as Jason was saying, these are generally reserved for a very select set of patients. So in patients with extensive portal venous thrombosis and no portosystemic shunt options, you might consider gastroesophageal devascularization.
DR. BINGHAM: Okay, and what's another one?
DR. DO: So in another setting, you might consider esophageal transection with division and anastomosis. But again, this is rarely used ever since TIPS has come into play.
DR. BINGHAM: Now, you mentioned devascularization. So what is meant by these devascularization procedures?
DR. DO: So this is essentially a total devascularization of the greater curvature and the upper two-thirds of the lesser curvature, as well as a circumferential devascularization of the lower 7.5 centimeters of the esophagus.
DR. BINGHAM: Okay, you also mentioned something about portosystemic shunts. Now, I know there's selective shunts, there's partial shunts, there's non-selective shunts. What do we mean by that? Kevin, why don't you take us through this one?
DR. KNIERY: So selective shunts is- generally, you want to go from selective to non-selective. So the selective shunt, the common one is the splenorenal or Warren shunt and this will decompress only part of the portal venous system and this is good for variceal bleeding, but does not help ascites. And so there's also a partial portosystemic shunt. These are types of side-to-side shunts where the flow is calibrated by the size of the synthetic interposition graft placed between the portal vein in the vena cava.
DR. KNIERY: And then of course, you have your non-selective portosystemic shunts and these will provide wide decompression of the entire portal venous system by doing something like a side portacaval shunt, but these have high rates of encephalopathy, and they complicate liver transplants later.
DR. BINGHAM: Yeah, so this is something where you kind of have to think about where your problem is, and I've seen, at least, practice questions laid out like this, where they give you a patient, and their main problem is variceal bleeding and not a main problem with ascites, then something like a selective shunt would be the way to go. If their main problem is ascites, you need a non-selective shunt, with the understanding that that's going to potentially worsen any encephalopathy. Okay.
DR. BINGHAM: So that's about as much of portal hypertension I can take. For some reason, I find that to be a very confusing topic, but hopefully, that'll help you get a few more points on that test. So let's move on to another very, very common thing, it's liver abscess. So they'll generally ask about three different kinds, pyogenic, amoebic, and echinococcal. So, Woo, what is a pyogenic liver abscess?
DR. DO: Yeah, so of those three categories, the pyogenic abscess is the most common, and it comprises over 80%. It's secondary to biliary tract infection, with E. coli being the most common pathogen. It can also happen secondary to spread from a GI source, such as diverticulitis or appendicitis.
DR. BINGHAM: How do you treat a pyogenic abscess?
DR. DO: And you treat these with percutaneous drainage as well as antibiotics.
DR. BINGHAM: Okay, so that's your pyogenic abscess, that's your most common. Those are bacteria from a GI source, most commonly from biliary tract infection. Perc drain, antibiotics. Kevin, amoebic abscess.
DR. KNIERY: So these are the patients that have just gotten back from traveling to South America or Mexico. These can be diagnosed based on imaging findings, and you also want to get serology on these patients to confirm the diagnosis. And these patients generally will respond to Flagyl and rarely need drainage of these.
DR. BINGHAM: Okay, last one. Yeah, so amoebic abscess, don't drain those, treat those with Flagyl. Woo, echinococcal cyst.
DR. DO: So echinococcal cysts are essentially Hydatid cysts. They have a characteristic double-walled cystic appearance on CT scan. Also, for these patients, just like your amoebic abscess patients make sure you check their serology. And to treat, the medical management here is albendazole followed by surgical excision. The key is not to aspirate or spill because spillage will cause anaphylaxis.
DR. BINGHAM: Perfect. Okay, well, I think that's a good place for us to break with our part 1 of the hepatobiliary, but before we do that, let's do a couple quick hits. Okay, Kevin, what's the hepatic vein pressure gradient typically required for a variceal rupture?
DR. KNIERY: It needs to be at least 12 mmHg.
DR. BINGHAM: Okay, and we said earlier, what's the definition of portal hypertension?
DR. KNIERY: Portal hypertension pressure begins at 6 mmHg.
DR. BINGHAM: Yep, so six is the definition of portal hypertension. You need about double that, or 12, before you get to variceal rupture. Woo, the Child-Turcotte-Pugh score, what are the components of that?
DR. DO: So bilirubin, albumin, prothrombin time, encephalopathy, and ascites.
DR. BINGHAM: Yep, so that's your Child score. Bilirubin, albumin, PT, encephalopathy, and ascites. How about the MELD score?
DR. KNIERY: The MELD score is thought to be more objective, and contains the bilirubin, the INR, and the creatinine.
DR. BINGHAM: Okay, great, and so what MELD score has it been shown to have-- a patient to have a survival benefit with transplantation?
DR. DO: 15.
DR. BINGHAM: Yep, so you need
DR. BINGHAM: a MELD score of 15 before you'll have a survival benefit from having a liver transplant. So Kevin, a common test question, important to know in real life, especially with increasing levels of cirrhotic patients in the United States, how do you manage a patient, a cirrhotic that comes in to you with an umbilical hernia?
DR. KNIERY: So you want to attempt to reduce this as quickly as possible, but you also want to make sure that you do everything possible to get medical control of the ascites before they need an operation, because that will significantly complicate the operation.
DR. BINGHAM: Yes, so let's just say it's a reducible umbilical hernia, they come in to you because it's caused them a little bit of pain. So how do you want to manage? It's not incarcerated, it's not strangulated. How do you want to manage that?
DR. KNIERY: So at that point in time, you can have them get on optimal medical management and just have them follow up for discussion of elective repair.
DR. BINGHAM: Okay and what if medical treatment's not working?
DR. KNIERY: So then you have to do intermittent paracentesis, temporary peritoneal dialysis catheters or potentially a TIPS procedure to help control the ascites.
DR. BINGHAM: Yeah, so if you're in an elective setting, get them absolutely medically optimized to reduce any chances of a recurrence, any chances of complications during the procedure. You have time on your side, use it. In an elective setting, do you want to use mesh, do you want to close it primarily, how do you want to do that?
DR. KNIERY: These patients have a high risk of recurrence due to their intra-abdominal pressure, so I would use a mesh in the elective setting.
DR. BINGHAM: Okay, what if you have a patient that comes in to you and their MELD score is 20, they're on the transplant list, and they're telling you, "Yeah, this bothers me." Do you want to fix that or what do you want to tell those patients?
DR. KNIERY: Hopefully, that they can wait to get this repaired at the same time they get their liver transplant.
DR. BINGHAM: Yeah, that just makes sense. If they're getting a liver transplant, take care of the hernia at the time of the liver transplant. So those are the easy ones. What about the complicated ones? If they come into the ER, they have a big red, angry, incarcerated, strangulated, umbilical hernia. What do you do there?
DR. KNIERY: Unfortunately, these are very difficult, but your only choice is to operate on them. So you must repair these urgently, and you can't use mesh in these situations due to the concern for infection. So in the cases we've seen of this, you reduce it, reduce the hernia, close in multiple layers, and you want to close the peritoneum, because your biggest problem post-operatively is going to be drainage of ascites.
DR. KNIERY: And then you want to have aggressive ascites control post-op and so sometimes people actually leave intraperitoneal drains to help drain the ascites to let the fascia and peritoneum heal before moving those drains.
DR. BINGHAM: So let's be very careful when we say that, when you say leave an intraperitoneal drain, are you saying, put some JP drains down inside the abdomen and get out or are you saying something different?
DR. KNIERY: So you want to have a drain that you can control, due to the potential that they could drain too much and become hypotensive and low protein--
DR. BINGHAM: Yeah, so I know some people are doing that with their umbilical hernia repairs in their cirrhotics with ascites, leaving like a temporary catheter that can be closed off, not just laying JP drains inside the peritoneum, because those are going to drain liters and liters and liters and you're not going to be able to keep up with it. I think the more common thing is to close and then perform intermittent paracentesis to control the ascites, but there are some places that are doing those temporary catheters.
DR. BINGHAM: But I probably wouldn't answer that, because I would stay away from leaving drains in a Board-type scenario. Okay, that does it for hepatobiliary part 1. Everybody take a break, go outside, do something, go for a run, and then come back for part 2.