creation date: 2025-11-20 15:48
tags: Pathologies
Choledocholithiasis
Background
Definitions
Choledocholithiasis refers to the presence of stones within the common bile duct.
Etiology and Pathogenesis
The etiology and pathogenesis mirrors that of cholelithiasis.
Formation
In normal physiology, primary bile acids are formed from cholesterol in the liver mediated by vitamin C and are soluble.
Gallstones are formed from bile products that precipitate out of the solution including:
- Cholesterol
- Products from the breakdown of red blood cells
- Mixture of calcium bilirubinate, phosphate, carbonate, palmitate, and cholesterol
as well as substances such as postaglandins and lecithin which promote crystallization.
Biliary stasis is a key contributor in gallstone formation. Some causes of impaired gallbladder emptying include:
- Bowel rest
- Prolonged total parenteral nutrition
- Pregnancy
Cholesterol stones
An increase in cholesterol concentration in bile and decrease in bile salts and lecithin results in hypersaturated bile that precipitates as cholesterol and calcium carbonate. These make up 70% of stones.
Risk factors include:
- Obesity, insulin resistance, dyslipidemia
- Female sex (estrogen causes bile rich in cholesterol, progesterone relaxes smooth muscle and can cause bile stasis)
- Multiparity or pregnancy
- Family history
- Drugs: fibrates, estrogen therapy, OCPs
- Malabsorption
- Rapid weight loss
Black pigment stones
Black pigmentation is due to increased hemolysis causing increased in conjugated bilirubin uptake. Bilirubin precipitation results in black colouring of stones.
Risk factors include:
- Chronic hemolytic anemia
- Alcoholic cirrhosis
- Crohn disease
- Total parenteral nutrition
- Advanced age
Mixed pigment stones
Mixed or brown stones are due to infection or infestation causing damage to hepatocytes and the subsequent release of ß-glucuronidase which hydrolyzes conjugated bilirubin. Unconjugated bilirubin and fatty acids in bile precipitate as calcium carbonate, cholesterol, and calcium bilirubinate which is dark in colour.
Risk factors include:
- Bacterial infections and parasites in the biliary tract
- Sclerosing cholangitis
Secondary vs. primary choledocholithasis
Majority of cases of choledocholithiasis are secondary to passage from the gallbladder to the CBD.
With age, the size of the bile duct can increase which can result in bile stasis. In such cases, primary or intraductal stone formation may occur.
Sequelae of stone formation
The presence of stones in the CBD can result in an obstruction of bile flow. This can result in obstructive jaundice or hepatitis. Stagnant bile can also lead to bactilbilia and ascending cholangitis. In some cases, obstruction near the pancreatic duct can result in the obstruction of pancreatic enzymes and thus pancreatic inflammation.
Clinical Presentation
Signs & Symptoms
Most patients present with:
- Pain (right upper quadrant, epigastric, or chest) which is prolonged (>6 hrs)
- Nausea
- Vomiting
On physical exam, patients are typically afebrile. Courvoisier’s sign refers to a palpable gallbladder on exam due to dilation from CBD obstruction and may be present.
Laboratory findings may see:
- Elevated AST and/or ALT in early biliary obstruction (hepatocellular pattern)
- Elevated ALP later (cholestatic pattern)
- Conjugated bilirubin may be elevated
History & Physical Exam
Suspicion should be maintained in patients with elevated liver enzymes, especially with RUQ or epigastric pain.
It should be noted that choledocholithiasis is possible even in patients who have undergone cholecystectomy.
Risk factors
Diagnosis
Criteria
Diagnosis is made through visualization of stone within the bile duct. This can be made through:
- RUQ transabdominal ultrasound
- Magnetic resonance cholangiopancreatography (MRCP)
- Endoscopic ultrasound
A dilated bile duct is not diagnostic but raises the suspicion. A cutoff of 6 mm is typically used but may result in false positives in older patients.
Work-up
Initial workup consist of RUQ ultrasound and laboratory testing:
- CBC
- Liver tests
- Lipase (for pancreatitis)
Treatment can be initiated if any of the following are seen:
- Cholangitis (eg. fevers, chills, leukocytosis, dilated bile duct)
- Stone visualized
- High suspicion (bilirubin >4 AND CBD >6mm (or >8mm if cholecystectomy))
In patients without the above features, further testing is indicated:
- MRCP or endoscopic ultrasound
ERCP is typically reserved for therapeutic purposes due to the risk of complications.
Differential
Biliary pain (intermittent and short episodes (<6 hrs)):
- Uncomplicated gallstone
- Sphincter of Oddi dysfunction
- Functional gallbladder disorder
Biliary pain (prolonged):
- Acute cholecystitis - bilirubin not significantly elevated and ALP normal
Jaundice has a number of alternative diagnoses but is differentiated by dilated CBD and biliary type pain.
Red Flags / Complications
Complications can include:
- Acute pancreatitis
- Acute cholangitis
- Liver abscess
- Cirrhosis
Management
Choledocholithiiasis without complications
Management generally consist of removal of bile duct stones. If the patient has cholelithiasis, cholecystectomy should be performed to reduce further risk. In the absence of cholangitis, stone removal is not urgent.
Options include:
- Cholecystectomy with intraoperative ERCP (best approach but only available in some centres)
- ERCP followed by cholecystectomy (most common)
- Cholecystectomy with CBD exploration (higher risk of biliary leak)
- Cholecystectomy followed by ERCP (rare)
Cholangitis
In patients with cholangitis, endoscopic retrograde cholangiopancreatography (ERCP) is indicated for stone removal followed by cholecystectomy. The standard cholangitis management includes:
- Antibiotics
- Supportive cares
Pancreatitis
In patients with pancreatitis without cholangitis, non-urgent ERCP is indicated if biliary obstruction is present. If cholangitis and biliary obstruction is absent, ERCP is not indicated but continued monitoring should be performed.
Following recovery, cholecystectomy should be performed to prevent recurrence.