A biliary stricture is any blockage in the biliary tree, whether due to an obstruction within the ducts, damage of the bile duct walls, or deformities. A blocked bile duct will affect the outflow of bile from the liver and cause it to back up in the biliary tree (cholestasis). Eventually this damages the hepatocytes thereby leading to liver disorders like cirrhosis.
The various causes of bile duct blockages may affect the extrahepatic (outside of the liver) or intrahepatic biliary tree (within the liver). Some causes may affect any part of the biliary tree. Refer to Bile Duct Anatomy for more information on the biliary tree.
The increase in surgery and invasive diagnostic procedures of the biliary tree and gallbladder these days makes iatrogenic causes of biliary strictures fairly popular. Biliary atresia is a congenital deformity that may cause partial or complete occlusion of the biliary tree. It is one of the rare but serious causes of neonatal jaundice.
Biliary strictures may remain asymptomatic for long periods of time if the blockage is slight. It may be missed for prolonged periods until it leads to symptoms like stone formation, abdominal pain, obstructive jaundice, nausea or vomiting or change sin stool color (pale or clay colored). At times it is only detected upon routine liver function tests (LFT) for other hepatobiliary conditions or insurance screening. The ALP (alkaline phosphatase) and GGT (gamma-glutamyltranspeptidase) may be raised while other liver enzymes may be normal or borderline. Bilirubin may be slightly or significantly elevated depending on the extent of the obstruction.
Bile Duct Obstruction
The most common cause of an obstruction in the biliary tree is a bile duct stone (choledocholithiasis). This includes a stone or stones lodged in the common hepatic, cystic or common bile ducts. The causes, symptoms and treatment is discussed further under Bile Duct Stones.
Other causes of an obstruction within the duct may include :
- Parasites within the bile duct
- Catheters or stents
- Tumors
Compression from outside of the duct (extrinsic) may be seen with gallstones in the cystic duct, hepatitis causing compression of the intrahepatic biliary tree, tumors of the surrounding tissue (liver, pancreas, gallbladder, cystic duct, duodenum). Other causes of strictures may involve aneurysms (hepatic artery), diverticulum (duodenum) and Crohn’s disease.
Bile Duct Damage
Cholangitis is the inflammation of the bile ducts. Swelling due to inflammation may narrow the duct slightly but it is the fibrotic scarring that arises from chronic inflammation that will cause a more significant occlusion. Cholanigitis is frequently due to bacterial infections, although viral, fungal and parasitic infections may also be involved. Other causes of inflammation include injury due to surgery, invasive diagnostic procedures, catheters and stents, tumors and acute pancreatitis.
Primary biliary cirrhosis is inflammation of the bile duct walls often due to unknown reasons. It can affect any part of the biliary tree. It is believed that a large proportion of cases may be due to autoimmune causes, which may be triggered by an infection or attributed to genetic factors. Primary biliary cirrhosis is closely associated with liver cirrhosis.
Dilated Bile Duct
Choledochal cysts are dilatations of the common bile duct. It is a congenital abnormality and usually seen in children. The cysts increase the chance of bile duct stone formation or stenosis (narrowing) thereby causing blockages in the bile duct.
Tumors
Tumors may cause an obstruction within the bile duct or occur outside the duct and compress on the duct. It may be either malignant or benign. Malignancies may originate within the bile duct epithelium itself (primary) like with cholangiocarcinoma or secondary in that it spreads from the liver (hepatocellular carcinoma), pancreas (pancreatic cancer), gallbladder (gallbladder carcinoma), lymph nodes or metastases from distant sites.
Related Articles
Article reviewed by Dr. Greg. Last updated on October 31, 2010
Left side abdominal pain
Leg numbness
Right side abdominal pain
Numbness in arm
Intestinal parasites
Itchy Scalp
Excessive burping