Biliary atresia (BA) is a disorder in which the bile ducts within and outside the liver become obstructed and can lead to biliary cirrhosis and eventually liver failure, and is one of the most important gastrointestinal surgical disorders in the field of pediatric surgery.
Type I: common bile duct atresia (10% of the total).
Type II: common hepatic duct atresia (2% of the total).
Type III: hilar atresia (88% of the total).
The first two types are considered correctable (anastomotic) and type III is considered uncorrectable (non-anastomotic).
There are many causes for the pathogenesis of biliary atresia.
1, viral infection theory: research hotspots of the etiology focus on cytomegalovirus (CMV), rotavirus (RRV), euthero virus type III and human papillomavirus (HPV).
2. the immune damage doctrine.
3, graft-versus-host injury theory: graft-versus-host injury triggered by maternal microchimerism in humans may be involved in the development of BA.
4, genetic etiology theory: it is commonly believed that certain susceptibility genes may exist in BA patients, and they include DLK1, CTGF, ICAM-1, INV, CFC1, jagged1, MIF, etc.
5, dysplasia theory: failure of bile duct plate remodeling is an important theoretical basis for the BA dysplasia theory.
Symptoms of biliary atresia.
The performance of the child within 1-2 weeks after birth is mostly abnormal, often after the physiological jaundice subsides and then appear sclera and skin yellowing. As the jaundice continues to deepen with age, the urine color also deepens, even to a strong tea color. Some children are born with white clay-colored stools, but many children are born with normal fetal stools and feces, and as the jaundice deepens, the color of the stools gradually becomes lighter and eventually white clay-colored.
As jaundice worsens, the liver gradually enlarges and hardens, and the abdomen of the child becomes more pronounced and the spleen enlarges at the same time. In severe cases, there may be manifestations of portal hypertension such as angry abdominal wall veins, ascites, and bleeding from ruptured esophageal varices. As the child gets older, the disease progresses and gradually develops nutritional developmental disorders. Biliary cirrhosis develops due to long-term obstruction of the bile ducts, and impaired liver function leads to impaired absorption of fat and fat-soluble vitamins. If left untreated early, most children die of liver failure within one year of age.
Diagnosis of biliary atresia.
The diagnostic methods used for biliary atresia take many forms and vary in means, all requiring comprehensive analysis in conjunction with clinical and laboratory tests, supplemented by nuclear examinations, cholangiography and liver puncture biopsy. Early surgical investigation is recommended for those with difficult diagnosis.
1, dynamic observation of serum bilirubin weekly measurement of serum bilirubin, if the curve of bilirubin amount tends to decline with the course of the disease, it may be hepatitis; if it continues to rise, it suggests biliary atresia. However, when heavy hepatitis is accompanied by extrahepatic biliary obstruction, it may also show a continuous rise, which is difficult to identify.
If no gallbladder or a small gallbladder (less than 1.5 cm) is seen on ultrasonography, biliary atresia is suspected. If a normal gallbladder is seen, hepatitis is supported. If the distribution pattern of intrahepatic bile ducts can be seen, it will be more helpful for diagnosis.
3, 99mTc-diethyliminodiaceticacid (DIDA) excretion test has replaced 131 iodine-labeled rosacea excretion test in recent years, has a high rate of hepatocyte extraction (48%-56%) and is superior to other items. It can diagnose partial obstruction of the biliary tract due to structural abnormalities. If a common bile duct cyst or extrahepatic bile duct stricture occurs with complete obstruction, the scan does not show intestinal visualization and can be used as a differentiator for severe intrahepatic biliary depression. In the early stages of biliary atresia, the hepatocytes function well and the liver image is visible in 5 minutes, but no biliary tract image is seen later, even after 24 hours, and no intestinal image is seen. In neonatal hepatitis, the extrahepatic bile ducts are open and the intestinal tract is visualized, although the hepatocytes are not functioning well.
4, lipoprotein-X (Lp-x) quantification Lipoprotein-X is a low-density lipoprotein that is elevated in biliary obstruction. It has been studied that all cases of biliary atresia are elevated and are positive at a very young age, while neonatal hepatitis cases are negative in the early stages, but can turn positive with increasing age. If the birth is more than 4 weeks and Lp-X is negative, biliary atresia can be excluded; if >500mg/dl, biliary atresia is more likely. Can also take abciximide 4g / day, a total of 2-3 weeks, compare the indicators before and after the use of drugs, such as the level of decline to support the diagnosis of neonatal hepatitis syndrome, if it continues to rise, there is a possibility of biliary atresia.
5, quantitative determination of bile acids recently applied to the blood paper serum total bile acids quantitative method, biliary atresia when the total serum bile acids of 107-294μmol/L, generally considered to reach 100μmol/L are depressed bile, the same age without jaundice control group is only 5-33μmol/L, the average is 18μmol/L, so there is diagnostic value. Urinary bile acids are also a means of early screening. The mean urinary total bile acids in biliary atresia were 19, 93 ± 7, 53 μmol/L, compared to 1, 60 ± 0, 16 μmol/L in the control group, which was 10 times greater than normal children.
6, cholangiography ERCP has been applied for early differential diagnosis, and the following cases of biliary atresia were found on imaging.
(1) Only the pancreatic duct is visualized.
(2) Sometimes abnormal pancreaticobiliary duct co-flow can be detected, and both pancreatic duct and bile duct can be visualized, but intrahepatic bile duct is not visualized, suggesting intrahepatic type atresia.
Neonatal hepatitis syndrome has the following signs.
(1) Both pancreatic and biliary ducts are visualized normally.
(2) The common bile duct is visualized, but it is thin.
7, liver puncture pathological histological examination is generally advocated for liver puncture biopsy, or percutaneous liver puncture imaging and biopsy. Neonatal hepatitis is characterized by irregular arrangement of lobular structures, hepatocyte necrosis, giant cell degeneration and portal inflammation. The main manifestations of biliary atresia are marked bile duct hyperplasia and bile embolism, and periportal fibrosis, although multinucleated giant cells may be seen in some specimens. Therefore, liver biopsy can sometimes be diagnostically difficult or even wrong, and in 10-15% of cases the correct diagnosis cannot be made on the basis of this.
Treatment of biliary atresia.
1.Kasai surgery
BA treatment requires surgical methods to achieve, usually Kasai surgery is used to restore normal bile flow in order to achieve improvement in liver function and achieve long-term survival. If this surgery does not result in the jaundice subsiding or biliary cirrhosis occurring after surgery, liver transplantation is the only treatment option.
Kasai surgery is divided into open and laparoscopic procedures according to the surgical approach, which consists of three parts.
(1) dissection of the fibrous mass of the porta hepatis, which is probably the most important part.
(2) jejunal circuit reconstruction.
(3) hepaticojejunal anastomosis. The basic idea behind the Gussy procedure is that even if the extrahepatic bile ducts are atretic, there may be tiny remaining bile ducts near the hilum. If the fibrous mass of the porta hepatis can be moderately removed, the bile may drain smoothly and the patient may survive.
Since biliary atresia can develop progressively into cirrhosis and is irreversible after more than 3 months, surgery should be completed within 60 days after diagnosis, or within 6-8 weeks if biliary atresia cannot be distinguished from infantile liver syndrome.
2.Liver transplantation treatment
Liver transplantation is the only effective treatment for congenital biliary atresia that has progressed to the end stage. In pediatric patients (less than 18 years old), congenital biliary atresia accounts for nearly half of all liver transplants, including about 90% of those within 1 year of age. Approximately 67% of children following the Gussy procedure still require liver transplantation for salvage until adulthood, thus making the Gussy procedure a transitional treatment for patients prior to receiving liver transplantation. The successful use of liver transplantation for the treatment of children with BA has led to a significant increase in the demand for pediatric liver transplantation over the past 20 years. This has led to the widespread use of the following liver transplantation techniques: reduced volume liver transplantation, split liver transplantation, and living liver transplantation. The low weight of infants and children requires a small volume of donor liver, which must be a reduced-volume donor liver including split cadaveric and living donor livers. The increasing scarcity of cadaveric liver donor sources makes living liver transplantation more worthy of advocacy. This is because.
(1) expanded donor sources.
(2) living liver transplantation is mostly an elective procedure, so the donor and recipient can be adequately prepared to perform liver transplantation before the condition of the child deteriorates, reducing the mortality of the recipient while waiting for liver transplantation
(3) The cold ischemia time of the donor liver is reduced, thus improving the quality of the donor liver.
(4) Pre-operative CT and MRI examinations can be performed on the donor, thus helping to select the volume in the best proportion, making the transplanted liver more compatible with the recipient, and pre-operative examinations can also be performed to understand the anatomical factors such as blood vessels, facilitating vascular reconstruction.
(5) It is possible to obtain a more suitable histocompatibility match for the donor-recipient based on the results of ABO blood group, leukocyte antigen and HLA analysis.
(6) It helps to obtain a family psychological effect, so that the parents of the child can get a chance to save the child’s life through living liver transplantation.