Congenital intrahepatic bile duct cystic dilatation

　　The exact etiology of intrahepatic bile duct cystic dilatation (Caroli disease) is not yet fully clear. Most scholars believe that Caroli disease is a congenital disease caused by chromosomal recessive inheritance, which may be caused by congenital weakness of the bile duct structure or absence of sympathetic nerves.

　　Scholars have conducted correlation studies on congenital choledochal cysts, congenital intrahepatic bile duct cystic dilatation, and congenital liver fibrosis, and found that there is a certain relationship among them in pathogenesis, which may be the manifestation of the same disease spectrum at different sites. That is, choledochal cysts involve extrahepatic bile ducts, Caroli disease involves large intrahepatic bile ducts, and congenital liver fibrosis involves small intrahepatic bile ducts. The three can exist independently or simultaneously. In addition, literature reports that the incidence of carcinoma in Caroli disease is 2.5% to 15.0%.

　　Congenital bile duct cystic dilatation (Caroli's disease) can be complicated with intrahepatic bile duct calculi or intracystic calculi, which are caused by bile stasis and bile duct infection. The incidence of bile duct cancer in Caroli's disease is 7% to 15%, which is 100 times higher than that in the normal population. The mechanism of easy malignancy is that the mechanical stimulation of gallstones causes changes in the bile duct mucosa, and there are carcinogenic substances such as bile anthracene and methylcholanthrene in the biliary tract. Caroli is caused by congenital malformation, and even without bile stasis, cell畸变 is prone to occur and form a tumor. This disease may also be complicated with cholangitis and liver abscess, and 60% to 80% of patients have cavernous kidney.

　　This disease often has no symptoms in children or young adults, and symptoms usually appear after long-term bile stasis leading to gallstone formation and biliary tract infection. Abdominal pain, aversion to cold, fever, and jaundice are the main symptoms of the disease, which are similar to cholelithiasis and cholangitis, and are prone to misjudgment. Severe biliary tract infection can develop into biliary liver abscess and sepsis, and during the remission period, there may be no symptoms. Some patients may also have liver enlargement and tenderness due to recurrent biliary tract infection, which can eventually lead to liver cirrhosis and portal hypertension.

　　The etiology of this disease is not yet clear, and it may be related to environmental factors, genetic factors, dietary factors, and emotional and nutritional factors during pregnancy. Therefore, it is not possible to prevent the disease directly according to the etiology. Early detection, early diagnosis, and early treatment are of great significance for indirect prevention of the disease, and can also reduce the occurrence of infectious complications. For patients with infection, antibiotics should be used as soon as possible.

　　The laboratory examination of this disease is mostly normal except for slight elevation of alkaline phosphatase and gamma-glutamyl transpeptidase, and patients in the acute phase often have elevated white blood cells and abnormal liver function. This disease can also be supplemented with other auxiliary examinations:

　　1. Ultrasound

　　It can show the shape, size, and distribution of the cysts. Marchal et al. described the ultrasonic specific manifestations of Caroli's disease as bile duct dilation within the liver, spherical protrusions in the lumen, bridges extending from the bile duct wall into the lumen of the dilated bile ducts, and partial or complete encirclement of the small branches of the portal vein by the dilated bile ducts within the liver.

　　2. CT examination

　　The imaging features of Caroli's disease are characterized by a central dot-like shadow with cystic dilation after contrast-enhanced scanning, known as the 'central dot sign'. This is equivalent to the formation of portal vein small branches in the dilated bile ducts, and CT can also reveal relative stenosis of the bile ducts at the hilum, which is beneficial for preoperative evaluation and selection of surgical methods.

　　3, 99mTc isotope scanning

　　Excretory liver and gallbladder造影 can clearly show the communication between the cyst and the bile duct, and distinguish it from simple intrahepatic cysts. 99mTc liver scan, the retention time of 99mTc in the liver of patients with Caroli exceeds 120 minutes, while multiple liver cyst patients quickly eliminate it, showing a normal liver scan image.

　　4, Percutaneous liver biopsy cholangiography (PTC)

　　Endoscopic retrograde cholangiopancreatography (ERCP) examination PTC, although ERCP can clearly show the size and number of intrahepatic bile duct dilatation, it is an invasive examination that can lead to serious complications and induce biliary tract infection. Especially ERCP should be contraindicated in principle, and PTC examination can be used cautiously in some patients to clarify the relationship between the cyst group and the intrahepatic bile ducts and plan the surgical resection scheme. Antibacterial drugs should be used to prevent infection before and after the contrast agent.

　　5, Magnetic Resonance Cholangiopancreatography (MRCP)

　　Static water including bile duct and pancreatic duct secretions show high signal according to the heavy T2 weight sequence, while blood flow is signal-free due to the flow void effect. Therefore, MRCP can obtain good contrast without contrast agent, and can show the degree, location of intrahepatic bile duct dilatation, and the presence or absence of stones, etc.

　　Patients with congenital intrahepatic bile duct cystic dilatation should eat light and pay attention to a reasonable diet, ensuring comprehensive and balanced nutrition. Eat more vegetables and fruits, and eat less spicy and irritating foods.

　　The best treatment plan for congenital intrahepatic bile duct cystic dilatation (Caroli disease) is still controversial. Not all Caroli diseases require or can be effectively treated with surgery. For patients without biliary obstruction or symptoms of cholangitis, treatment can be temporarily omitted, and follow-up observation can be carried out. The purpose of surgery should be mainly to treat complications, and radical surgery is generally only used for localized lesions. The specific situation of surgical treatment is as follows:

　　One, surgical indications

　　1, patients with obvious clinical symptoms.

　　2, the cyst group is limited to a lobe or a segment, which can be completely resected by surgery.

　　3, with infection, both intrahepatic and extrahepatic bile duct stones.

　　4, with choledochal cystic dilatation.

　　5, suspected malignant or potentially resectable.

　　Two, surgical contraindications

　　Biliary tract infection and intrahepatic bile duct stones are the most common symptoms, the following situations of patients with Caroli should not be operated:

　　1, asymptomatic type II lesions (according to clinical classification) should avoid unnecessary surgery, especially禁忌 using ERCP examination.

　　2, lesions that cannot be corrected in children.

　　3, advanced carcinoma.

　　4, liver fibrosis in the late stage and liver dysfunction.

　　Three, selection of surgical methods

　　Ia type disease usually does not show changes in liver fibrosis, and generally the best effect can be achieved after the complete resection of the cyst group.

　　For type Ib central lesions, liver cysts, Chinese scholars in recent years believe that extensive cyst wall resection and large opening low drainage are the key to surgery. The surgical method is to try to resect the anterior wall of the cyst and part of the liver tissue to the porta hepatis, so that it is in a low drainage position of the liver, and then cut the end of the Roux-Y intestinal loop along the opposite margin of the mesentery to a sufficient size to cover all the openings to form a large opening, and anastomose the duodenum with an artificial papilla formed by the jejunojejunal stoma in the low cyst cavity, while resecting the remaining common bile duct cyst. This operation is different from the general cyst jejunal anastomosis.

　　Generally, it is not advisable to perform cystic internal drainage for extensive intraperitoneal cystic lesions, as the uncontrolled infection inside the cyst cannot be controlled due to poor drainage. However, for lower end of common bile duct obstruction and Flanigan Ⅳ type of common bile duct cystic dilatation, when combined with porta hepatis bile duct stenosis and partial obstruction, biliary-enteric anastomosis has been commonly considered in the past. The current view is that when the Oddi sphincter is normal, it should try to preserve the first-line defense function of the sphincter, and the stenosis can be repaired with gallbladder wall flap or other tissue flap without performing biliary-enteric anastomosis.

　　Some patients, after a long time of internal and external biliary drainage, the intraperitoneal cysts gradually shrink, and the nature of the drained bile gradually changes from the initial large amount, light color, turbidity, and much sediment to normal. The recurrence of intraperitoneal stones also decreases accordingly. This 'normalization' process takes a long time. The combined treatment method of internal and external drainage may provide an effective treatment for such extensive and complex Caroli disease patients, but there is no consensus on how long the external drainage tube needs to be placed. When the lesions invade both hemispheres, the treatment is often more difficult. Mercadier advocates for the removal of the expanded left hemihepatectomy to remove the stones in the expanded bile ducts of the right liver, and then perform an intraperitoneal biliary-enteric anastomosis. In recent years, Chinese scholars have observed the anatomy of the porta hepatis and adopted the method of extensive longitudinal incision along the right anterior segment of the hepatic duct branch to expose the opening of the right posterior branch of the hepatic duct and remove the stones, and combine the large-caliber high-position hepatic duct jejunum Roux-Y anastomosis method with internal and external drainage to treat this disease, with good results. Most of the Caroli disease can be long-term without the need for surgery after biliary resection, but if accompanied by recurrent cholangitis, severe liver cirrhosis, extensive bile duct dilatation leading to the terminal stage of liver fibrosis and bile duct cancer is not easy to resect, liver transplantation can be considered.