Biliary Atresia with Dr. Greg Tiao

In the pediatric patient population, biliary atresia is the most common cause of end-stage liver failure and the number one reason for pediatric liver transplant. So today, we're going to cover the basics of biliary atresia, with an expert. Dr. Greg Tiaw. He's a pediatric transplant surgeon at Cincinnati Children's Hospital Medical Center. Okay, so let's start with some basics. What is biliary atresia? Biliary atresia is a uncommon disease results in a obstructive cholangiopathy of the biliary system. It's unique to infancy and is the most common cause for end-stage liver disease in children. The etiology is uncertain. The end result is a biliary epithelial injury process that causes biliary obstruction. So, theoretically, what would happen if a child was never treated for their biliary atresia? The infant develops progressive cholestasis, portal fibrosis, eventually cirrhosis, and then the manifestations of that, which include portal hypertension, and if untreated, can cause death by age two years of age. What's the incidence of biliary atresia? And and I mean not just in the US. I mean like around the world. Biliary atresia is a sporadic disease process with varying incidence. In the far east, it's been estimated that one in 8,000 live births will result in a patient with biliary atresia. In the west, or especially in the United States, it's less common, where the incidence is one in 15,000 live births. How does a patient with biliary atresia present? This child or the infant is typically jaundiced. That's the first clinical manifestation. They will have acholic, or very pale gray stools. They'll have dark urine. Their liver will become quite firm, so it's usually palpable uh in in the right costochondral margin. Typically, the age group that they present is between one to two months of age. But with screening, you can actually pick it up at an earlier stage. And that screening has uh has been demonstrated to improve the outcome of patients who are detected at an earlier age. Is biliary atresia a common cause for jaundice and an infant? Well, the most common reason that a infant has jaundice is actually physiologic jaundice of the newborn. If it's a indirect hyperbilirubinemia, then that's physiologic jaundice. If it's a direct hyperbilirubinemia, then you actually have to be worried that there's a more pathologic process underway. Okay, great. So look at the type of hyperbilirubinemia first. Once we've done that, what should be on the differential diagnosis for a patient with direct hyperbilirubinemia? The differential diagnosis once you've established a direct hyperbilirubinemia, can be broken down into two groups. There's the anatomic causes, or the way I think about it is the anatomic causes. That would be biliary atresia, occasionally choledocal cysts, and there's something that's rare but is still on the differential diagnosis: inspissated bile syndrome. And then there's hepatocellular or nonanatomic causes of jaundice, and that's going to include the viral hepatitis, uh sepsis, and then uh hepatocellular specific abnormalities, which include Alagille's, progressive familial intrahepatic cholestasis syndromes. Alpha-1 antitrypsin deficiency on occasion can present in that way. And then there's some even less common specific intracellular pathway abnormalities that can cause cholestasis. This includes tyrosinemia and some transport abnormalities. So how do you work up biliary atresia? You get a liver profile including a GGT. Remember, the liver profile includes AST, ALT, direct, indirect and total bilirubin, total protein, and albumin. It's a great place to start with the workup. You'll get an alpha-1 antitrypsin genotype. You'll get a torch workup. And remember, torch, that's a mnemonic to help you remember the infectious agents that can affect the developing fetus. It stands for T, toxoplasmosis. O is other, R is rubella, C is cytomegalovirus, and H is herpes virus. Okay, keep going. And then of course you also these kids will be have screen for cystic fibrosis, hypothyroidism, and very rarely galactosemia, but that's all part of the perinatal screening process. So are there any new studies we should consider in the workup? More recently, from a laboratory standpoint, there's been some new studies showing that the protein MMP7, a matrix metalloproteinase 7, is a new biochemical marker that has very high diagnostic sensitivity and specificity for biliary atresia. What about imaging? What should we get first? The ultrasound is the first imaging test that you'll typically obtain. Can we get a hiata scan? I mean we use it for other biliary pathology. Does it apply here? The hiata scan was used for many years, but that test it's fairly sensitive, but its specificity is quite low. And so it's usually not utilized because it can actually delay the workup and diagnosis of biliary atresia. Can we do an ERCP? Occasionally teams will have the capacities to do a endoscopic retrograde cholangiopancreatogram, an ERCP. All right, cut to the chase. How do we definitively diagnose biliary atresia? And then of course the gold standard for biliary atresia is a liver biopsy. What is the pathologist looking for on that biopsy? The classic findings of biliary atresia on that biopsy is expansion of the periportal space with a mononuclear cells. You'll see bile duct proliferation, and then the pathognomonic finding of biliary atresia is bile duct plugs within those proliferating periportal biliary ducts. Okay, what are the treatment options? So the treatment options for biliary atresia in this day and age remain surgical. And those include a Kasai portoenterostomy or a liver transplantation. Are there any preoperative considerations to keep in mind? Most teams will find that as long as they get the patient to the OR before 70-75 days, the success rate of the procedure justifies the small morbidity risks of the procedure. As you get patients who are older, this is when you have to start worrying about manifestations of cirrhosis, which include ascites and theoretically coagulopathy. That may tell you that the patient's disease process is more advanced and that consideration for primary transplant is warranted. Okay, so are we at the good part yet? Are we ready to operate? Is there anything else we need to do first? Both of those procedures require a intraoperative cholangiogram, that just to establish anatomy, to try to visualize there is any patency of the common hepatic duct and the intrahepatic components of the process. Great. So we get our intraoperative cholangiogram and confirm atresia. Now let's get into the steps of the Kasai procedure. To expose the Hylam, we'll mobilize the gallbladder out of its bed, identify the common bile duct and the common hepatic duct. You'll carry your dissection out laterally to where the arteries begin to branch. Once you've completed that dissection, you'll have really a triangle like appearance of the hylar plate, where it will extend from the common hepatic duct down to kind of the broader base of the triangle. This is the classic finding of a patient with biliary atresia. And then in one sharp transaction, divide that Hilar plate right proximal to Glisson's capsule. We'll create a 30 to 35 cm Ruen Y limb, we'll bring it up in a retrocolic fashion and then proceed with our reconstruction or hylar plate reconstruction. What are the postoperative complications to keep an eye out for? The most worrisome complication is if you cause a vascular injury of some sort to the portal vein or to the hepatic artery. This goes to during a Kasai, we really try not to divide anything that is easily demonstrable. What I mean by that is if you think it's a vessel, don't divide it, because you'd be surprised how oftentimes you think it's nothing and it turns out to be a segmental artery of importance. The other complications occasionally patients can have a bile obstruction, they can have some wound issues. All right, anything else we should watch out for? One of the concerns we have longer term is cholangitis, but of course, for cholangitis you actually have to have adequate bile flow to even begin to have that. So it's almost if you have cholangitis, that's actually a good thing in the sense that you actually obtained drainage, but then the patient developed, we presume an ascending process. And this can be suppressed with antibiotics. What's the typical postoperative period look like for these patients? Immediate postoperative period the patient will be on a surgical service. In the United States most patients are discharged home within five to seven days after the procedure. Then they'll follow up both with the surgeon and a gastroenterologist, because this does require multidisciplinary care. Um patients will be on prophylactic antibiotics, they'll typically on actigall, and then they'll require nutritional support both in fat soluble vitamins and elemental diets as they kind of nurse their liver back into health. How do we measure surgical success? The definition of a successful Kasai is a direct bilirubin under two at three months of age. What we're looking for immediately post-op is a pigmented stool. If we see that, we know the patient is draining. And then we'll monitor those patients as an outpatient and typically around two to three months we'll be looking for the direct bilirubin to be less than two. So there you have it. The basics of biliary atresia from presentation to workup and diagnosis all the way through surgery and post-operative management. If you liked this episode, go ahead and follow us on social media, subscribe to our YouTube channel, like, comment, and probably more importantly, download the Stay Current in Pediatric Surgery app. We've got content like this and so much more for you. So go to the Apple App Store, the Google Play Store, download it today. But until then, I'm Todd Ponksy from Cincinnati Children's. I'm Ellen Enscisco from Cincinnati Children's. I'm Rod from Cincinnati Children's. And remember, knowledge should be free.