Biliary atresia (BA) is a cholangiodestructive disease affecting biliary tract, which ultimately leads to cirrhosis, liver failure and death if not treated. The incidence. Biliary atresia is a serious condition that affects infants. It is characterized by hepatic bile ducts, the bile ducts in the liver that do not. Liver and intrahepatic bile ducts – nontumor – Extrahepatic biliary atresia.
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Biliary atresia BA is a cholangiodestructive disease affecting biliary tract, which ultimately leads to cirrhosis, liver failure and death if not treated. The incidence is bilir in Asian countries than in Europe. For these infants the aetiology lies within the first trimester of gestation.
For others affected with BA, aetiology is more obscure and perinatal destruction of fully-formed ducts perhaps by the action of hepatotropic viruses has been suggested.
Whatever the cause, the lumen of the extrahepatic duct is obliterated at a variable level and this forms the basis for the commonest classification Types Atrewia, II, III. All patients with BA present with varying degree of conjugated jaundice, pale non-pigmented stools and dark urine.
Key diagnostic tests include ultrasonography, biochemical liver function tests, viral serology, and in our centre a percutaneous liver biopsy. In some centres, duodenal intubation and measurement of intralumenal bile is the norm. Currently BA is being managed in two stages. The first stage involves the Kasai operation, which essentially excises all extrahepatic biliary remnants leaving a transected portal plate, followed by biliary reconstruction using a Roux loop onto that plate as a portoenterostomy.
If bile flow is not restored by Kasai procedure or life-threatening complications of cirrhosis ensue then consideration should be given to liver transplantation as a second stage. The outcome following the Kasai operation can be assessed in two ways: Biliary atresia BA is a cholangiodestructive disease affecting both the intra- and extra-hepatic biliary tract ultimately leading to cirrhosis, liver failure and death if not treated.
Whatever be the cause, the end result is invariably complete obliteration of the lumen of extrahepatic bile ducts and progressive cellular inflammation of the intra-hepatic ducts. In some infants, there is evidence to suggest that the process begins early in gestation. Thus antenatal ultrasonography allows detection of that sub-group of BA that show cystic changes within the extrahepatic ducts.
These anomalies are unusual but characteristic such as polysplenia, asplenia, situs inversus, absence of inferior vena cava and pre-duodenal portal vein, for which we have coined the term Biliary Atresia Splenic Malformation BASM syndrome. There are some histological similarities between the appearance of developing bile ducts at the porta hepatis at weeks gestation and the appearance of the residual biliary ductules at the porta hepatis in BA patients, suggesting that even some cases of isolated BA the disease may be due to alterations in early bile duct development and failure of remodeling.
Alternatively, BA may arise due to damage of a fully-developed biliary tract at some point in post-or at least perinatal life. Thus some studies report an association of various gastrointestinal viral infections with BA including reovirus type 3,[ 10 — 13 ] cytomegalovirus,[ 1415 ] respiratory syncitial virus,[ 16 ] Epstein-Barr virus,[ 17 ] human papillomavirus[ 18 ] and rotavirus type A.
There are also various animal models that can mimic some of the pathological features of BA and which rely upon exposure of the newborn animal to viruses such as rotavirus and reovirus.
Genetics may play a role in the pathogenesis of BA, atdesia in predisposing to the detrimental effects of hepatotropic viral infection. Although in most, this plays probably a fairly minor role as the usual evidence for a genetic background is missing.
Familial cases of BA have been rarely reported[ 28 — 31 ] and discordance has been reported in monozygotic twins. The gross appearance of the extrahepatic biliary tract varies from an inflamed, hypertrophic occluded biliary tract to an atrophic remnant. Histologically, the liver has features of portal tract inflammation, with a small cell infiltrate, bile ductule plugging and proliferation.
The lumen of the extrahepatic duct is obliterated at a variable level and this forms the basis for the commonest classification in clinical use – the Japanese Association of Pediatric Surgeons JAPS classification [ Figure 1 ]. In type 2 BA, atresia extends up to common bile duct, whereas in type 1 BA, atresia extends up to common hepatic duct level. Some cysts contain mucus, while others contain bile. If it is bile, there may be diagnostic confusion with that of a true choledochal cyst.
In cystic biliary atresia, the wall is invariably thickened, lacks an epithelial lining and communicates poorly with abnormal non-dilated intrahepatic ducts. This should be evident at operative or percutaneous cholangiography.
All patients with BA present with varying degree of jaundice, clay-colored stools and dark yellow urine.
Failure to thrive, coagulopathy and anemia are also not uncommon. Some will present with signs of advanced disease and cirrhosis such as ascites, umbilical hernia, prominent abdominal veins and respiratory discomfort. In comparison to European or North American experience, most cases in developing countries present late.
The clinical diagnosis of BA is usually all too obvious in late-presenting cases. Key investigations include ultrasonography, biochemical liver function tests, viral serology, and a percutaneous liver biopsy. In some centers, duodenal intubation and measurement of intralumenal bile is the routine test for BA. Newer modalities such as ERCP[ 37 ] and Biluer have been used at times, although the former is clearly highly operator-dependent and the atrresia not sufficiently precise in its delineation of infantile biliary anatomy to offer real advantage.
Ayresia, in most surgical centers, operative cholangiography remains the principal investigation in demonstrating biliary patency. This can also be performed laparoscopicaly with apparently good results. Liver function tests LFTs: LFTs are abnormal in all patients of BA.
Alkaline phosphatase and transaminase e. Deranged LFTs correspond to the degree of parenchymal damage rather than the duration of disease. Hepatobiliary ultrasound after 12 h of fasting with intravenous fluid support is perhaps the initial investigation of choice.
Certainly BA is highly unlikely if a dilated intrahepatic biliary duct is found being more indicative of an obstructed choledochal cyst, or inspissated bile syndrome. Percutaneous liver biopsy after exclusion of medical causes of cholestatic jaundice e. ERCP may be considered in infants with equivocal biopsy results, although it should be noted that this diagnosis depends crucially on failure to show a biliary tree, and hence appropriate experience and judgment are essential.
This is particularly so in the inspissated bile syndrome group, when not only can the diagnosis be established but an attempt at therapeutic saline lavage also can be made. About half of this group can be treated effectively without the need for laparotomy and without any recurrence or long-term sequelae. Excretion of Technetium-labeled isotopes into the gut within 24 h, establishes the patency of the biliary tract.
However, iblier negative scan even after 24 h may still atresix consistent with both BA and an advanced stage of neonatal hepatitis.
Negative HIDA scans may be repeated after atressia week of phenobarbitone therapy, if clinically indicated. Phenobarbitone is known to stimulate the hepatic enzymes and increase the flow of bile. Alternatively, further improvements have been suggested with the addition of betamethasone to phenobarbitone prior to HIDA scanning. Sometimes the interpretation of a biopsy can be difficult and needs an experienced pathologist as there is a lot of overlap in the histological finding of BA and neonatal hepatitis.
There is also an inherent risk of bleeding in performing needle artesia. A four-hourly duodenal aspiration is done to confirm the presence of bile in it.
What is Biliary Atresia: Symptoms, Causes, Diagnosis, and Treatment
Again, the test may be falsely negative in patients with severe neonatal hepatitis. In most centers, having excluded medical causes of jaundice and failed to show isotope excretion in a HIDA scan, then progression to peroperative cholangiogram is a reasonable option.
The key observation at laparotomy is presence or absence of bile in the gallbladder. Clearly in the presence of bile, apart from the rare type 1 cases, then BA can be excluded. A cholangiogram through the gallbladder should demonstrate the entire biliary tree, but in those cases, where only the distal common bile duct CBD opacifies, an attempt should be made to delineate the proximal intrahepatic tree by application of a distal vascular clamp.
The major breakthrough in the surgery for biliary atresia was seen in when Morio Kasai reported the operative relief of biliary obstruction in infants traditionally considered to have non-correctable biliary atresia. Once the diagnosis of BA is established the liver should be mobilized fully outside of the abdominal cavity by division of its suspensory ligamentsto ensure maximal exposure of the porta hepatis and facilitate a detailed dissection.
The atretic gall bladder, cystic duct and all the remnant extrahepatic biliary tree are excised up to the level of the porta hepatis. The portal dissection itself must be wide extending from exposure of the origin of the umbilical vein from the left portal vein in the Rex fossa to the bifurcation of the right portal vein pedicle. Small veins from the portal vein to the portal remnant should also be divided to expose the caudate lobe posteriorly.
The correct level of transaction is flush with the liver capsule, where the plane is usually self-evident. Transgression into actual liver parenchyma, however, adds nothing to the success of surgery. Modifications such as an intussusception valve, stomas or implanting the distal end of the Roux into the duodenum have no real advantages in clinical practice and have been discontinued in most centers. Various technical variants have been proposed according to the anatomical pattern of the biliary remnant.
Hepaticojejunostomy may be possible in Type 1 BA although a complete excision and portoenterostomy even in these is probably a better option. If the gallbladder and distal common bile duct are patent then anastomosis of the opened gallbladder to the conduit to the transected portal plate porto-cholecystostomy is possible and avoids post-operative cholangitits.
A number of drugs have been suggested to try and improve postoperative results. For instance, there are anecdotal and uncontrolled studies suggesting benefit from corticosteroids,[ 4647 ] ursodeoxycholic acid[ 47 ] and even Chinese herbs.
Early postoperative complications include: The cause of cholangitis is not clear but there must be an intestinal-biliary communication and therefore the most favored hypothesis is that of an ascending infection from the gut.
Treatment includes resuscitation, intravenous fluid, broad spectrum antibiotics, and in some centers high doses of steroids for 7—10 days. In recurrent or late-onset cholangitis, obstruction to the drainage of the Roux loop should be considered. Historically, various measures have been tried with to reduce cholangitis although none have stood the test of time.
Pathology Outlines – Extrahepatic biliary atresia
These include stomas or catheters in the taresia limb of the Roux loop,[ 5455 ] use of an omental wrap applied to the porta hepatis,[ 56 ] jejunal loop “valves”,[ 57 ] creation of an intussuscepted ileocecal conduit[ 58 ] and use of an appendiceal conduit based on its vascular pedicle.
In a recent study, it was found that increased portal pressure measured at the time of Kasai operation is a bad prognostic sign.
This study reported that portal pressure index height of the saline level column above the liver surface level was safe, simple and better predictor of postoperative outcome than a hepatic fibrosis score. In patients with good liver function, varices are treated with endoscopic sclerotherapy or banding;[ 62 ] but in those with persisting jaundice, poor synthetic liver function, this will only be temporizing measure and liver transplantation is the only really successful option.
Interventional radiological techniques such as transjugular intrahepatic portosystemic shunts TIPS are possible for some cases, as a bridge to transplantation, but require skill and perseverance if good results are to be obtained. Portal vein hypoplasia may even preclude this option. In those unusual cases of life-threatening bleeding, but non-progressive liver disease and good liver function, a conventional portosystemic shunts should be considered, particularly if transplantation is not an option.
Hepato-pulmonary HP syndrome is characterized by hypoxia, cyanosis, dyspnoea and clubbing and is due to development of pulmonary arterio-venous shunts. This seems to be due to gut-derived vasoactive substances that are not cleared by the cirrhotic liver. The diagnosis is made by pulmonary scintigraphy. HP syndrome can be reversed after liver transplantation.
Pulmonary hypertension can also be a late complication of the cirrhotic liver[ 64 ] and can be diagnosed by echocardiography. In some, liver transplantation may be indicated. Bile containing cysts can develop in the liver postoperatively even in patients with complete clearance of jaundice.
If infection and cholangitis supervene then such bile lakes can be drained either externally or internally by cyst-enterostomy.
Ultimately, liver transplantation may be required as this usually implies marked degenerative cirrhotic change.