Biliary Strictures — Narrowing of the Bile Ducts

What Are Biliary Strictures?

Biliary strictures are abnormal narrowings of the bile ducts that impede the normal flow of bile from the liver to the small intestine. These narrowings can occur anywhere along the biliary tree — from the intrahepatic bile ducts within the liver to the distal common bile duct near the pancreas. Biliary strictures can be benign or malignant, and distinguishing between the two is one of the most important challenges in their management.

Benign vs. Malignant Causes

Benign Biliary Strictures

• Post-surgical — the most common cause of benign strictures, occurring after cholecystectomy (gallbladder removal), liver transplantation, or hepatobiliary surgery
• Chronic pancreatitis — fibrosis of the pancreatic head can compress and narrow the distal bile duct
• Primary sclerosing cholangitis (PSC) — a chronic autoimmune disease causing multifocal biliary strictures
• IgG4-related sclerosing cholangitis — an autoimmune condition responsive to steroid therapy
• Post-radiation therapy
• Ischemic strictures — after hepatic artery thrombosis, particularly following liver transplantation

Malignant Biliary Strictures

• Cholangiocarcinoma — bile duct cancer
• Pancreatic cancer — tumors of the pancreatic head
• Gallbladder cancer
• Ampullary carcinoma
• Metastatic disease — lymph node metastases compressing the bile duct

Symptoms

Biliary strictures typically present with symptoms of biliary obstruction:

• Jaundice — yellow discoloration of the skin and eyes, which may be intermittent (benign) or progressive (malignant)
• Pruritus (itching) — caused by bile salt deposition in the skin
• Dark urine and pale stools
• Right upper quadrant pain — may be episodic or constant
• Cholangitis — recurrent episodes of fever, jaundice, and abdominal pain indicate infected bile above the stricture
• Weight loss — more concerning for malignant causes

Diagnostic Pathway

• Blood tests — cholestatic liver enzymes (elevated ALP, GGT, bilirubin). Tumor markers (CA 19-9) can be elevated in both malignant and some benign conditions.
• MRCP — the preferred non-invasive imaging study for mapping the biliary tree and characterizing the stricture location, length, and morphology
• Endoscopic Ultrasound (EUS) — EUS is excellent for evaluating distal strictures, detecting small masses, and obtaining tissue samples via FNA/FNB
• ERCP with brush cytology — ERCP provides direct imaging (cholangiography) and tissue sampling. Brush cytology, although specific, has limited sensitivity. Advanced techniques including fluorescence in situ hybridization (FISH) improve diagnostic yield.
• Cholangioscopy (SpyGlass) — direct visualization of the bile duct wall during ERCP allows targeted biopsies and visual characterization of the stricture
• CT scan — evaluates for masses and distant disease

Treatment

Benign Strictures

Endoscopic treatment via ERCP is the first-line approach for most benign biliary strictures:

• Balloon dilation — a balloon catheter is inflated within the stricture to stretch and widen it
• Plastic stent placement — one or more plastic stents are placed across the stricture and exchanged every 3 months over a period of 12 months. This gradual dilation protocol achieves long-term resolution in 80-90% of post-surgical strictures.
• Fully covered self-expanding metal stents (FCSEMS) — an alternative approach using a single removable metal stent left in place for several months
• Endoscopic stenting techniques continue to evolve with improved outcomes

Malignant Strictures

• Palliative stenting — self-expanding metal stents placed via ERCP provide durable biliary drainage with longer patency than plastic stents
• Preoperative drainage — biliary stenting before planned curative surgery when jaundice is severe or surgery is delayed
• Surgical resection — when the underlying malignancy is resectable

Follow-Up

Regular follow-up is essential after treatment of biliary strictures:

• Scheduled stent exchanges every 3 months for plastic stents in benign strictures
• Blood tests (liver function, bilirubin) to monitor for recurrence
• Imaging (MRCP or ultrasound) as needed
• For malignant stents: monitoring for stent occlusion and re-intervention as needed
• Patients with PSC require ongoing surveillance including screening for cholangiocarcinoma

Prognosis

For benign strictures, endoscopic management achieves long-term success in 80-90% of cases. Post-surgical strictures have the best outcomes. PSC-related strictures may recur and require repeated interventions. For malignant strictures, the prognosis depends on the underlying cancer type and stage. Metal stent patency typically ranges from 6 to 12 months, and re-intervention is possible when needed.