Biliary atresia

Introduction Biliary Atresia (BA) is a common malformation in pediatric surgery characterized by intrahepatic and extrahepatic bile duct atresia and obstructive jaundice. Due to liver and gallbladder developmental disorders during embryonic period, it is difficult to diagnose before delivery. Kasai surgery is the first-line treatment of the disease, but in the end 70% of children with BA who have successfully used Kasai surgery develop cirrhosis and need liver transplantation. Congenital biliary atresia is a kind of obstruction of intrahepatic and extrahepatic bile ducts, which can lead to cholestatic cirrhosis, congenital biliary atresia and eventually liver failure. It is one of the most important digestive diseases in the field of pediatric surgery, and it is also a pediatric liver. The most common indications for transplantation.

Cause

There is no clear conclusion on the cause. The disease is considered to be a congenital biliary dysplasia in the early stage, which is related to the developmental pause or disorder of the bile duct system during the 4th to 10th week of embryonic period. However, biliary atresia has not been found in the anatomy of a large number of abortions or premature biliary systems. In contrast, recent studies have shown more evidence to support the formation of the disease. Some of the sick children had normal yellow stools at birth, and grayish white stools and jaundice appeared only a few weeks later, suggesting that these pediatric biliary obstructions did not occur until after birth. In addition, pathological examination revealed inflammatory changes in the liver tissue, inflammatory cell infiltration around the hilar and bile duct, microscopic pus or localized necrosis in the hepatic lobule, and granulation tissue in the bile duct occlusion. By comparing the pathological study of extrahepatic biliary atresia and neonatal hepatitis, it was found that the liver tissue lesions were similar, only to a different extent. Extrahepatic biliary atresia is mainly characterized by bile duct biliary thrombosis and inflammatory lesions, while infant hepatitis hepatocyte necrosis is more prominent. Therefore, biliary atresia is now considered to be an acquired disease similar to the pathological process of infant hepatitis. Biliary atresia seen after birth is the terminal stage and outcome of the inflammatory process, which causes scarring and occlusion of the bile duct fibers. The cause of inflammation is mainly viral infection, such as hepatitis B virus, cytomegalovirus, etc. It may also be rubella virus, hepatitis A virus or herpes virus. Some scholars have suggested that abnormalities in the confluence of pancreaticobiliary ducts may also be congenital factors in the occurrence of biliary atresia.

Although the cause of this disease is many, the end result is obstruction of bile excretion pathway and obstructive jaundice. Recent studies have shown that the development of intrahepatic and extrahepatic biliary tracts is two sources, which can explain the patency of the ducts below the gallbladder in the biliary atresia, and the occlusion of the lumen above the hepatic bile duct.

an examination

Related inspection

CT imaging of liver, gallbladder and spleen with cholangiography

There are many experimental methods but the specificity is poor. When biliary atresia, serum total bilirubin increased. The abnormally high value of alkaline phosphatase has a reference value for diagnosis. A high peak of -glutamyltransferase above 300 IU/L is a persistently high level or rapidly increasing state. The higher the level of 5' nucleotidase in the bile duct hyperplasia, the higher the measured value is >25 IU/L, the red blood cell hydrogen peroxide hemolysis test method is more complicated, if the hemolysis is more than 80%, it is positive.

1. Dynamic observation of serum bilirubin

Serum bilirubin is measured weekly. If the bilirubin amount curve decreases with the course of the disease, it may be hepatitis. If it continues to rise, it suggests biliary atresia, but severe hepatitis with extrahepatic biliary obstruction may also be persistent. Ascending, at this time it is difficult to identify.

2. Ultrasound imaging examination

If the gallbladder is not seen or there is a small gallbladder (less than 1.5cm), it is suspected to be biliary atresia. If there is a normal gallbladder, it supports hepatitis. If you can see the distribution of intrahepatic bile ducts, it can help diagnose.

3.99mTe-diethyliminodiaceticacid (DIDA) excretion test

In recent years, the 131 iodine-labeled rose red excretion test has been substituted for higher hepatocyte extraction rate, which is superior to other items. Can diagnose partial obstruction of the biliary tract due to structural abnormalities, such as choledochal cyst or extrahepatic bile duct cholangiography stenosis, when complete obstruction occurs, the scan does not show intestinal visualization, can be used as an identification of severe intrahepatic cholestasis. In the early stage of biliary atresia, hepatocytes functioned well, showing liver shadows in 5 minutes, but no biliary tract development was seen in the future, and no intestinal development was observed even after 24 hours. When neonatal hepatitis, although liver cells function poorly, but outside the liver The biliary tract is smooth and the intestine is developed.

4. Lipoprotein-X (Lp-x) quantitative determination

Lipoprotein-X is a low density lipoprotein that is elevated in biliary obstruction. According to the study, all cases of biliary atresia were elevated and were positive at very young age. Neonatal hepatitis cases are negative in the early stage, but can also be converted positive by age. If the birth has been more than 4 weeks and Lp-X is negative, biliary atresia can be excluded, such as >500mg/dl, the possibility of biliary atresia is large. Can also take cholestyramine, compare the indicators before and after medication, such as decreased content to support the diagnosis of neonatal hepatitis syndrome, if continued to rise, there may be biliary atresia.

5. Quantitative determination of bile acid

Recently used in blood paper tablets serum total bile acid quantitative method, serum total bile acid at the time of biliary atresia is 107-294mol / L, it is generally considered that up to 100mol / L are spleen. There is no jaundice in the same age, the control group is only 5-33mol/L, and the average is 18mol/L, so it has diagnostic value. Urinary bile acid was also an early screening method. The average urinary bile acid was 19.93±7.53mol/L in biliary atresia, while the control group was 1.60±0.16mol/L, which was 10 times larger than normal children.

6. Cholangiography

ERCP has been applied to early differential diagnosis. The angiography found that biliary atresia has the following conditions: (1 only pancreatic duct development; 2 sometimes pancreaticobiliary duct abnormalities can be found, pancreatic duct and bile duct can be developed, but intrahepatic bile duct is not developed, suggesting intrahepatic type Blocked. Neonatal hepatitis syndrome has the following signs: 1 the pancreatic duct is normal; 2 common bile duct development, but fine.

7. Liver puncture histopathological examination

It is generally recommended for liver biopsy or percutaneous liver biopsy and biopsy. Neonatal hepatitis is characterized by irregular lobular structure, hepatocyte necrosis, giant cell changes, and portal inflammation. The main manifestations of biliary atresia are obvious hyperplasia of bile ducts and bile embolization, fibrosis around the portal vein, but some specimens can also see multinucleated giant cells. Therefore, liver and bile biopsy can sometimes cause difficulty in diagnosis or even error.

Differential diagnosis

The disease is differentiated from the following diseases:

1. Neonatal hepatitis: This disease is most difficult to identify with neonatal hepatitis. Some scholars believe that biliary atresia and neonatal hepatitis may be different pathological changes of the same disease. About 20% of neonatal hepatitis has a complete biliary obstruction stage, and the performance of obstructive jaundice is very similar to biliary atresia. However, most of the extrahepatic biliary tracts of these children are normal, and splenomegaly is rare. After general treatment, after 4 to 5 months, the biliary tract is cleared, and the jaundice gradually subsides, which can be cured naturally. Therefore, through long-term clinical observation, a differential diagnosis can be made. If congenital biliary atresia can be performed within 2 months, biliary reconstruction can be performed, and a good bile drainage effect can be obtained. The liver has been caused by biliary cirrhosis for more than 3 months. Irreversible damage, even if the surgery is not effective, so early differential diagnosis is very important.

(1) Clinical identification points: more male infants than female infants, and more biliary atresia than male infants; hepatitis jaundice is less fluctuating, jaundice persists in biliary atresia, yellow soft stool in hepatitis, biliary atresia The color appears earlier and lasts longer. When the biliary tract is locked, the liver is heavier than hepatitis, and the texture is hard, often accompanied by splenomegaly.

(2) Laboratory identification:

1 serum bilirubin: children with hepatitis gradually decreased with the course of the disease, biliary atresia continued to rise.

2 alkaline phosphatase: neonatal hepatitis rarely exceeds 40U, decreases with the improvement of hepatitis, and biliary atresia continues to increase.

3 activation of serum leucotranspeptidase: only 23% of cases of neonatal hepatitis exceed 500U.

4 Determination of serum 5'-nucleotidase, biliary atresia increased the concentration of this enzyme, neonatal hepatitis patients generally do not exceed 25U / L.

5 serum bile acid determination: biliary atresia is significantly higher than neonatal hepatitis serum bile acid, dynamic observation is more meaningful.

6 serum alpha-fetoprotein determination: hepatocyte proliferation in neonatal hepatitis, alpha-fetoprotein synthesis increased, the concentration increased, if the peak is greater than 40ng / dl can be diagnosed as neonatal hepatitis. Biliary atresia is mainly bile duct epithelial hyperplasia, no hepatocyte proliferation, so serum alpha-fetoprotein is negative, very little positive, the average is low, the difference between the two is obvious.

(3) Auxiliary inspection:

1 Determination of bilirubin in the duodenal drainage: Duodenal fluid without bilirubin, 90% of congenital biliary atresia, help early diagnosis of congenital biliary atresia.

2131I-RB excretion test and 99mTc-PL scan: normal 131I-RB after intravenous injection, for liver polyhedral cells and excreted through the bile to the intestine, not absorbed by the intestine, biliary atresia in children with red rose in the liver Entering the intestine, the amount of 131I in the feces can be determined to understand the biliary obstruction. Generally, the amount of 131I in the feces was measured after injecting the vein for 2 hours at 2 UC/kg. 90% of the biliary atresia 131I was less than 5% with fecal excretion, and almost all children with neonatal hepatitis were above 10%. The 99mTc-PL scan also aids in the identification of biliary atresia and neonatal hepatitis.

3 liver biopsy: neonatal hepatitis is mainly caused by hepatic parenchymal cell disease, while biliary atresia is mainly caused by bile duct system and portal vein lesions. Although there is no characteristic change in pathological changes of biliary atresia and neonatal hepatitis, there is only a difference in severity. However, the area of the portal area, the bile and the lobes in the lobular area within the unit area are significantly different between the two diseases.

Type 4B ultrasound: Intrahepatic bile duct, common bile duct, and gallbladder are normal images in neonatal hepatitis, but the extrahepatic biliary tract of biliary atresia cannot be detected, the gallbladder is small or not developed, and the liver is accompanied by splenomegaly.

5 percutaneous transhepatic cholangiography (PTC): This test can not only be used to identify biliary atresia and neonatal hepatitis, and children with biliary atresia can perform PTC examination before surgery to understand the lesions of the intrahepatic and extrahepatic biliary tract, determine the obstruction site, This determines the procedure.

2. Neonatal hemolysis: This disease is similar to biliary atresia in the early stage. There are jaundice, hepatosplenomegaly, etc., but the child has severe anemia. The peripheral blood is like a lot of nuclear red blood cells. As the sick child grows up, the blood picture returns to normal.

3. Neonatal lactating jaundice: the disease is caused by the inhibition of the activity of glucuronyl transferase by certain substances in breast milk. Generally, the jaundice is aggravated 4 to 7 days after birth, the deepest in 2 to 3 weeks, and the blood bilirubin is up to 15 ~ 25mg / dl, 2 to 4 days after stopping the milk, hyperbilirubinemia quickly subsided, the disease is clinically no hepatosplenomegaly and gray stool.

4. Congenital choledochal cyst: The disease is jaundice, abdominal mass, grayish white feces, but jaundice is intermittent, B-ultrasound can be found in liquid level lumps.

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