Choledocholithiasis and Biliary Obstruction

Choledocholithiasis is the presence of gallstones in the common bile duct, and it is the most frequent cause of extrahepatic biliary obstruction. When a stone impedes bile drainage, pressure rises behind it and bile constituents are retained, producing obstructive jaundice and setting the stage for complications such as cholangitis and pancreatitis.

Definition

Choledocholithiasis is the presence of one or more calculi within the common bile duct, which may partially or completely obstruct bile flow and cause extrahepatic (post-hepatic) cholestasis.

Scope

The topic covers how common-duct stones arise and migrate, the physiology of obstruction and the resulting cholestatic picture, the principal complications of an obstructed duct, and the role of imaging and endoscopic drainage in characterising the obstruction. It is reference material describing the disease entity rather than individualised clinical guidance.

Core questions

• How do stones reach and lodge in the common bile duct?
• What is the physiological consequence of obstructing bile flow at the common duct?
• How does biliary obstruction produce jaundice and a cholestatic biochemical pattern?
• What complications follow an obstructed, stone-bearing bile duct?

Key concepts

• Common bile duct stones
• Secondary versus primary duct stones
• Extrahepatic (post-hepatic) cholestasis
• Obstructive jaundice
• Ductal dilatation
• Gallstone pancreatitis
• Endoscopic retrograde cholangiopancreatography (ERCP) and ductal clearance

Mechanisms

Most common-duct stones are secondary — they form in the gallbladder and migrate through the cystic duct into the common bile duct; primary stones may also form within the ducts, particularly where bile is stagnant or infected. A stone that lodges in the duct raises intrabiliary pressure, dilates the proximal ducts, and impairs the secretion and drainage of bile. Bile constituents are retained, producing conjugated hyperbilirubinaemia and a cholestatic enzyme pattern with elevated alkaline phosphatase and gamma-glutamyl transferase. Stasis behind the obstruction predisposes to bacterial infection of the bile (acute cholangitis), and impaction of a stone at the ampulla can obstruct the pancreatic duct and precipitate gallstone pancreatitis. Diagnosis relies on imaging and cholangiography, and relief of the obstruction restores bile flow.

Clinical relevance

Choledocholithiasis is a leading cause of obstructive jaundice and a gateway to cholangitis and biliary pancreatitis, so recognising the obstructive cholestatic pattern is central to evaluating biliary disease. This entry explains the disease mechanism and its consequences for reference; it is not a protocol for diagnosis, drug selection, or procedural decision-making.

Epidemiology

Common bile duct stones are found in a substantial minority of people with symptomatic gallbladder stones, and the great majority are secondary stones that have migrated from the gallbladder. The overall burden tracks that of gallstone disease, which is common in Western populations.

History

Bile duct stones and obstructive jaundice were recognised clinically long before they could be visualised, but the field was transformed by direct cholangiography and especially by endoscopic retrograde cholangiopancreatography, which allowed both imaging and minimally invasive clearance of the duct, displacing open surgical exploration for many patients.

Seminal works

• williams-2017
• lammert-2016
• portincasa-2006

Frequently asked questions

Where do common bile duct stones come from?

Most are secondary stones that form in the gallbladder and migrate into the common bile duct; less often, primary stones form within the ducts themselves, typically in settings of bile stasis or infection.

Why is an obstructing bile duct stone dangerous beyond causing jaundice?

Stasis of bile behind the obstruction predisposes to infection of the biliary tree (acute cholangitis), and a stone impacted at the ampulla can block the pancreatic duct and trigger gallstone pancreatitis.