Your gallbladder stores bile until you eat, then releases bile into your small intestine to help digest food. Bile is made in the liver. It contains a mix of products such as bilirubin, cholesterol, and bile acids and salts. Bile ducts are drainage "pipes" that carry bile from the liver to the gallbladder and from the gallbladder to the small intestine.
A variety of diseases can affect your bile ducts. All block the bile ducts in some way, which is why the various diseases cause similar symptoms.
Gallstones are the most common cause of blocked bile ducts. Stones typically form inside the gallbladder and can block the common bile duct, the drainpipe at the base of the liver. If the duct remains blocked, bilirubin backs up and enters the blood stream. If bacteria above the blockage accumulates and backs up into the liver, it may cause a severe infection called ascending cholangitis. If a gallstone stops in between the gallbladder and the common bile duct, an infection called cholecystitis may occur.
Less common causes of blockages include cancers of the bile duct (cholangiocarcinomas) and strictures (scars that narrow the ducts after infection, surgery or inflammation).
Other bile duct diseases are uncommon, and include primary sclerosing cholangitis and primary biliary cirrhosis. Typically diagnosed in mid-adulthood, these conditions create ongoing inflammation in the bile duct walls, which can narrow and scar the walls. Primary sclerosing cholangitis is more common in people with inflammatory bowel disease (ulcerative colitis or Crohn's disease). Primary biliary cirrhosis is more common in women. It is sometimes associated with autoimmune diseases such as Sjögren's syndrome, thyroiditis, scleroderma or rheumatoid arthritis.
Biliary atresia is a rare form of bile duct blockage that occurs in some infants two weeks to six weeks after birth, a time when the bile ducts have not completed their development normally.
The chronic conditions of primary sclerosing cholangitis, primary biliary cirrhosis and biliary atresia can result in inflammation and scarring of the liver, a condition known as cirrhosis.