What is Choledocholithiasis?
Choledocholithiasis is the presence of stones in the common bile duct (CBD), a condition that affects approximately 10-20% of patients with gallbladder stones and requires intervention even when asymptomatic due to serious risks including obstructive jaundice, cholangitis, acute pancreatitis, and potentially secondary biliary cirrhosis. 1, 2
Pathophysiology and Clinical Significance
- The majority of CBD stones originate in the gallbladder and then migrate into the common bile duct, where they cause symptoms due to biliary obstruction 2
- Approximately 3-10% of patients undergoing cholecystectomy will have common bile duct stones 3
- The presence of multiple small gallstones (<5 mm) in the gallbladder creates a 4-fold risk for migration of these stones into the CBD 4
Clinical Presentation
- Choledocholithiasis can range from being completely asymptomatic to causing life-threatening complications such as acute cholangitis, which requires prompt biliary decompression 1
- Common presentations include obstructive jaundice (elevated bilirubin), cholangitis (infection of the bile ducts), and acute pancreatitis 1
- Laboratory findings typically show elevated bilirubin, alkaline phosphatase (ALP), and liver enzymes 4
Diagnostic Approach
Initial Imaging
- Abdominal ultrasound is the recommended initial diagnostic test, though it has limited sensitivity (22.5%-75%) for detecting CBD stones due to overlying bowel gas obscuring the subhepatic common duct 4
- Ultrasound is highly accurate for detecting biliary obstruction (sensitivity 32-100%, specificity 71-97%) and can show CBD dilatation, but often cannot identify the specific cause 4
- A normal CBD caliber on ultrasound has a 95-96% negative predictive value for choledocholithiasis 4
Advanced Imaging for Confirmation
- For moderate-risk patients, MRCP (magnetic resonance cholangiopancreatography) or endoscopic ultrasound (EUS) should be performed, with sensitivities of 93% and 95% respectively 1
- High-risk patients should proceed directly to ERCP (endoscopic retrograde cholangiopancreatography), intraoperative cholangiography, or laparoscopic ultrasound depending on local expertise 1
- Contrast-enhanced CT is very sensitive (74-96%) and specific (90-94%) for detecting biliary obstruction and can determine the site and cause more accurately than ultrasound 4
Key Clinical Pearls
- Sustained elevation of alkaline phosphatase is significantly correlated with choledocholithiasis on MRCP and may be helpful for triaging patients to ERCP 4
- Patients who have common bile duct stones demonstrated on ultrasound should proceed directly to ERCP without additional imaging 4
- When biliary ductal dilatation is identified on ultrasound but no stone is visible, other etiologies must be considered: only 36% of such cases are due to CBD stones, while 24% are due to strictures from chronic pancreatitis or prior stone passage, 16% are due to malignant obstruction, and 24% have no identifiable cause 5