Coledoco: What is it? Types of Ducts, Biliary Obstruction and Risk Factors

It is the tube of the liver and the gall bladder through which the bile passes into the small intestine and flows into the second portion of the duodenum.

What is a biliary obstruction?

A biliary obstruction is a blockage of the bile ducts. The bile ducts carry bile from the liver and gallbladder through the pancreas to the duodenum, which is part of the small intestine. Bile is a dark green or yellowish-brown fluid secreted by the liver to digest fats.

After eating, the gallbladder releases bile to aid digestion and absorption of fat. Bile also helps cleanse the liver of waste products.

The obstruction of any of these bile ducts is known as biliary obstruction. Many of the conditions related to biliary obstructions can be treated successfully. However, if the blockage is not treated for a long time, it can lead to potentially fatal liver diseases.

Types of bile ducts

You have several types of bile ducts. The two types of bile ducts in the liver are intrahepatic and extrahepatic ducts.

Intrahepatic ducts: intrahepatic ducts are a system of smaller tubes inside the liver that collect and transport bile to the extrahepatic ducts.

Extrahepatic ducts: the extrahepatic ducts start as two parts, one on the right of the liver and the other on the left. As they descend from the liver, they unite to form the common hepatic duct. This runs directly into the small intestine.

The bile duct, or the gallbladder duct, also opens into the common hepatic duct. The bile duct from this point on is known as the common bile duct or choledochol. Before emptying into the small intestine, the common bile duct passes through the pancreas.


A biliary obstruction can be caused by a number of factors that involve:

  • Bile ducts
  • Liver.
  • Gallbladder.
  • Pancreas.
  • Small intestine.

The following are some of the most common causes of biliary obstruction:

  • Gallstones, which are the most common cause.
  • Inflammation of the bile ducts.
  • Trauma.
  • A biliary stricture, which is an abnormal narrowing of the duct.
  • You are crying
  • Enlarged lymph nodes
  • Pancreatitis.
  • An injury related to surgery of the gallbladder or liver.
  • Tumors that have reached the liver, gallbladder, pancreas or bile ducts.
  • Infections, including hepatitis.
  • Parasites
  • Cirrhosis or scarring of the liver.
  • Severe damage to the liver
  • Choledochal cyst (present in babies at birth).

Which are the risk factors?

The risk factors for biliary obstruction generally depend on the cause of the obstruction. Most cases are the result of gallstones. This makes women more vulnerable to develop a biliary obstruction. Other risk factors include:

  • A history of gallstones.
  • Chronic pancreatitis.
  • Pancreatic cancer.
  • An injury in the right part of the abdomen.
  • Obesity.
  • Rapid weight loss
  • Conditions related to the breakdown of red blood cells, such as sickle cell anemia.


The symptoms of biliary obstruction may depend on the cause of the obstruction. People with biliary obstruction usually have:

  • Stool light colored.
  • Dark urine.
  • Jaundice (yellowing eyes or skin).
  • Itch.
  • Pain in the upper right part of the abdomen.
  • Nausea.
  • Vomiting
  • Weightloss.
  • Fever.


Several tests are available for people who may have a biliary obstruction. Depending on the cause of the obstruction, your doctor may recommend one or more of the following tests.

Blood test

A blood test includes a complete blood count (CBC) and a liver function test. Blood tests can usually rule out certain conditions, such as:

  • Cholecystitis , which is an inflammation of the gallbladder.
  • Cholangitis, which is an inflammation of the common bile duct.
  • An elevated level of conjugated bilirubin, which is a waste product of the liver.
  • A high level of liver enzymes.
  • An increased level of alkaline phosphatase.
  • Any of these may indicate a loss of bile flow.


Ultrasonography is usually the first test performed on anyone with suspected biliary obstruction. It allows your doctor to see gallstones easily.

Radiograph of biliary radionuclides (HIDA scan)

An exploration of hepatobiliary iminodiacetic acid, or HIDA scan, is also known as a bile radionuclide scan. It uses radioactive material to provide valuable information about the gallbladder and possible obstructions.


A cholangiogram is an x-ray of the bile ducts.

Magnetic resonance

An MRI scan provides detailed images of the liver, gallbladder, pancreas, and bile ducts.

Magnetic resonance cholangiopancreatography (MRCP)

Magnetic resonance cholangiopancreatography (MRCP) is used to diagnose biliary obstructions and pancreatic disease.

Endoscopic retrograde cholangiopancreatography

An endoscopic retrograde cholangiopancreatography involves the use of an endoscope and an x-ray. It is a diagnostic and therapeutic tool.

It allows your surgeon to see the bile ducts and is also used in the treatment. This tool is particularly useful because your doctor can use it to remove stones and take biopsy samples if necessary.