What causes the stenosis of the lower end of the common bile duct?

The incidence of stenosis of the lower end of the common bile duct is relatively high in my country, and it does not have a specific population of patients. Both newborns and the elderly are likely to suffer from stenosis of the lower end of the common bile duct. This is related to the complexity of its cause. It should be noted that there are many causes of stenosis of the lower end of the common bile duct. So what is the specific cause of the stenosis of the lower end of the common bile duct?

The lower common bile duct usually refers to the bile duct located between the lower edge of the duodenum and the ampulla of Vater. In recent years, with the widespread development of imaging techniques such as retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiography (MRCP), and endoscopic ultrasound (EUS), and the gradual improvement of endoscopic diagnosis and treatment techniques, the clinical understanding of this group of diseases has become increasingly clear. This article provides an overview of the etiology of the stenosis of the lower common bile duct.

stone

The most common cause of lower common bile duct stenosis is stones. Common bile duct stones refer to stones located in the common bile duct. According to their source, they can be divided into primary common bile duct stones and secondary common bile duct stones from the gallbladder. The clinical manifestations of common bile duct stones and the severity and danger of the disease depend entirely on the degree of stone obstruction and the presence or absence of bile duct infection. Although less common than gallbladder stones, common bile duct stones are the most common cause of extrahepatic obstructive jaundice, severe or fatal infections (such as cholangitis), pancreatitis, or chronic liver disease. The diagnosis of common bile duct stones should be considered in cases of extrahepatic obstructive jaundice.

Inflammation

The second is the stenosis caused by inflammation. Secondary cholangitis is mostly localized lesions, often secondary to stones, surgical trauma, T-tube drainage, tumors, parasites and other factors to form benign inflammatory stenosis. The pathological manifestations are congestion and edema of the tube wall mucosa, even ulcer formation, hyperplasia of scar fibrous tissue, thickening of the tube wall, and narrowing of the lumen. Infectious factors play an important role in the pathogenesis of lower common bile duct stenosis.

If clinical suspicion of lower common bile duct stenosis is present, further examinations may include: non-invasive examinations: CT, MRI, B-ultrasound, scintigraphy, ultrasound-secretin test, EUS, etc. Injurious examinations include: ERCP, SOM (endoscopic hepatopancreatic sphincter manometry), etc. ERCP is not only highly accurate in diagnosing lower common bile duct stenosis, but can also perform related treatments at the same time, with the advantages of less pain and fewer complications. The disadvantage of ERCP is the risk of inducing pancreatitis and retrograde infection.

In fact, the stenosis of the lower end of the common bile duct is not only caused by stones and inflammation, but also by bile duct tumors or biliary ascariasis. Moreover, the normal value of the inner diameter of the common bile duct needs to be differentiated according to different ages, and the normal value of the inner diameter of the common bile duct in different countries or races may also be different. I hope you can understand this.