Bile Duct Infection (Cholangitis) and Obstruction (Stricture)

What is cholangitis?

Cholangitis is the medical term for inflammation of the bile ducts. The most common cause is a bacterial infection which arises as a result of pathology within the bile ducts, usually a bile duct blockage. The bile ducts carry bile from the liver and gallbladder into the duodenum. It is also joined by the pancreatic duct which transports the pancreatic enzymes, water and bicarbonate into the duodenal lumen. This is explained further under Bile Duct Anatomy.

If there is any obstruction within the bile duct, the flow of bile is impaired and the local defense mechanisms that protect the bile ducts from infection are also disrupted. Bacteria, usually from the duodenum, may travel up the bile ducts where it results in an infection. If the bacteria enter via the liver into the bile ducts, then it is known as ascending cholangitis.

Causes of Cholangitis

Most cases of acute cholangitis are due to a bacterial infection. The following bacteria are more commonly involved :

  • Escherichia coli
  • Klebsiella spp
  • Enterococcus spp
  • Streptococcus spp
  • Enterobacter spp
  • Pseudomonas aeruginosa

The bacterial infection seen in acute cholangitis arises as a complication of other bile duct pathology :

  • Bile duct stones
  • Biliary strictures
  • Following ERCP (endoscopic retrograde cholangiopancreatography), cholecystectomy (gallbladder removal surgery)
  • Tumors – bile duct, pancreatic, ampulla of Vater
  • Acute pancreatitis
  • Fungal, viral or parasitic infections

In severe cases, the bile ducts fill with pus and this type of cholangitis is known as suppurative cholangitis.

Primary sclerosing cholangitis is seen in chronic liver disease where repeated inflammation of the bile duct leads to scarring and narrowing. Acute cholangitis (bacterial infection of the bile duct) may be seen repeatedly in primary sclerosing cholangitis.

AIDS-related cholangitis is seen in patients within HIV/AIDS and may be due to viral infections of the bile ducts.

Signs and Symptoms of Cholangitis

Cholangitis arises in the presence of other bile duct and related disorders. Therefore the clinical presentation may include the signs and symptoms of the predisposing pathology.

  • Abdominal pain – right upper quadrant (right hypochondrium) and upper middle abdomen (epigastrium) which may radiate to the back or right shoulder.
  • Fever with/without chills
  • Nausea and/or vomiting
  • Yellow skin – obstructive jaundice
  • Dark urine
  • Pale stools or clay colored stools
  • Itchy skin – pruritis
  • Malaise

It is not uncommon for patients to report repeated episodes of biliary colic prior to the onset of cholangitis symptoms.

What is a biliary stricture?

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.

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.

Causes of Stricture

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.

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.