Bile Duct Strictures - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Narrowing the bile duct, intrahepatic or extrahepatic, is called bile duct strictures. It can be either benign or malignant depending upon the causative disorders, but most cases are malignant. Constriction of the bile duct reduces bile flow, causing proximal dilatation and resulting in bile obstruction and complications.

What Causes Bile Duct Strictures?

Bile duct strictures can be mainly acquired or sometimes congenital. The acquired strictures are classified into benign and malignant.

Benign Strictures: These strictures contribute to approximately 30 % of biliary stricture cases, including the iatrogenic stricture. During laparoscopic cholecystectomy, there can be misidentification of the bile duct or cystic duct, leading to injury in the bile duct. These injuries could be partial or complete, and they can lead to bile duct strictures in an extended stay.

Some other benign causes of strictures are:

• Acute Cholangitis: A chronic syndrome that presents jaundice, abdominal pain, and fever due to stasis and infection in the bile duct.

• Mirizzi Syndrome: Extrinsic compression in the cystic duct or infundibulum of the gallbladder due to an impacted stone leading to obstruction.

• Chronic Pancreatitis: Inflammation of the pancreas for a long time that does not heal.

• Ischemic Cholangiopathy: Multiple diffuse intrahepatic strictures lead to a set of disorders.

• Biliary Inflammatory Pseudotumors: Benign, rare, and poorly defined tumors typically diagnosed post-aggressive surgical intervention.

• Orient cholangiohepatitis is characterized by intrahepatic or extrahepatic bile duct strictures and dilation with an intraductal pigmented stone.

• Post radiation or radiotherapy.

Anastomotic Strictures: These complications occur after orthotopic liver transplantation or a Whipple procedure performed for pancreatic mass or trauma.

Malignant Strictures: The most common etiology of bile duct stricture is malignancy, such as pancreatic head cancer and cholangiocarcinoma.

Some other malignancies involved are:

• Hepatocellular Carcinoma: Liver cancer in people with chronic liver diseases such as cirrhosis due to hepatitis infection. It is the most common type of liver malignancy.

• Lymphoma: It is a cancer of the lymphatic system of the body. The lymphatic system comprises lymph glands, spleen, thymus, and bone marrow.

• Periampullary Cancer: It includes a group of heterogeneous neoplasms (malignant lesions) arising from the distal common bile duct, head of the pancreas, and duodenum.

• Gallbladder Carcinoma: Malignancy infecting the gallbladder helps store and transport bile from the liver to the intestine.

How Does Bile Duct Stricture Look?

The obstruction of bile flow leads to elevated serum bilirubin and obstructive jaundice. Magnetic resonance cholangitis pancreatic (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP) show that benign strictures have smooth and symmetric borders with tapered margins. At the same time, malignant strictures have irregular and asymmetric borders with shouldered margins. Benign generally involves small segments in contrast to malignant which involves long segments.

What Is the Strasberg-Bismuth Classification of Strictures?

This classification helps guide the treatment and management of bile duct strictures according to their size and location.

• E1: Standard hepatic duct division greater than two centimeters from the bifurcation.

• E2: Standard hepatitis duct division less than two centimeters from the bifurcation.

• E3: Common bile duct dividing at the bifurcation.

• E4: Hilar stricture, which involves junction and loss of communication between the left and right hepatobiliary duct.

• E5: Involvement of aberrant hepatic duct with associated stricture of the common hepatic duct.

What Are the Symptoms of Bile Duct Strictures?

• Bile duct strictures can be asymptomatic with no relevant physical examination.

• Some cases of bile duct strictures may suffer from obstructive jaundice, which includes yellowing of mucosa, skin, presence of pale stools, and dark urine.

• The obstruction will lead to irregular indigestion leading to symptoms like loss of appetite, nausea, vomiting, fever, and malaise.

How to Diagnose Bile Duct Stricture?

The first step in investigating the disorder is physical examination. It helps to look for features such as Murphy and Courvoisier signs that diagnose jaundice and the presence of any hard masses in the abdomen pointing towards advanced malignant processes.

Other important investigating options are:

• Deranged Liver Function Test: Coagulative profiles help to understand invasive conditions. The presence of specific immunological markers helps to obtain an accurate diagnosis.

• Presence of Assay of CA19-9 and carcinoembryonic antigen in patients with suspected hepatobiliary malignancies.

• CT (computed tomography) scan helps detect the appearance and complications of strictures.

• Ductal dilatation is a significant feature in evaluating bile duct stricture. It is done with a trans-abdominal ultrasound which shows biliary dilatation and is highly sensitive to biliary obstruction levels.

• MRCP (magnetic resonance cholangiopancreatography) provides high-quality cholangiograms, which help establish the location and extent of biliary strictures. It provides a three-dimensional reconstruction and cross-sectional view of the biliary tree.

• ERCP (Endoscopic retrograde cholangiopancreatography) helps find the cause and acquire tissue samples for cytology and histology.

What Is the Treatment of Bile Duct Strictures?

The central management of bile duct strictures is restricted to treating complications from biliary obstruction and causative agents. The first line of treatment for biliary strictures is endoscopic treatment.

The options for treatment include:

• Stenting: This method manages both benign and malignant bile duct strictures. Reduction of hyperbilirubinemia or cholangitis is made before definitive surgery. This step is beneficial for palliation in malignant stricture, which is inoperable.

• Dilatation: This process is used to manage benign stricture. The balloon dilatation technique is used extensively for strictures caused due to primary sclerosing cholangitis.

• Resection and Anastomosis: This technique depends on the nature of strictures, whether malignant or benign, and on the outcome, which can be palliative or curative.

• Bypass: Choledochoduedenostomy can be involved in some instances as hepaticojejunostomy can make it challenging to perform ERCP in the future.

Conclusion:

Bile duct strictures obstruct bile flow due to constrictions in the bile duct. It can be intrahepatic (duct inside the liver) or extrahepatic (duct outside the liver). The symptoms can be biliary complications. The treatment is endoscopic approaches such as stenting, bypass, dilatation, and resection.