eMedicine Specialties > Gastroenterology > Biliary

Choledocholithiasis: Differential Diagnoses & Workup

Author: Imad S Dandan, MD, Consulting Surgeon, Department of Surgery, Trauma Section, Scripps Memorial Hospital
Coauthor(s): Assaad M Soweid, MD, Assistant Professor, Department of Internal Medicine, American University of Beirut, Lebanon; Firass Abiad, MD, Head of Division, General and Laparoscopic Surgery, Specialized Medical Center Hospital, Saudi Arabia
Contributor Information and Disclosures

Updated: Jul 16, 2008

Differential Diagnoses

Other Problems to Be Considered

Sclerosing cholangitis
Cholangiosarcoma

Workup

Laboratory Studies

• Laboratory tests are helpful, but results are not specific for the diagnosis of choledocholithiasis. As mentioned earlier, patients with choledocholithiasis are often asymptomatic, and, in such patients, laboratory test results can be completely normal. Finding a laboratory test that can help identify asymptomatic CBD stones and thus reduce the need for invasive testing remains a major diagnostic challenge.
• Patients with cholangitis and pancreatitis have abnormal laboratory test values. Importantly, a single abnormal laboratory value does not confirm the diagnosis of choledocholithiasis, cholangitis, or pancreatitis; rather, a coherent set of laboratory studies leads to the correct diagnosis.
  • WBC count elevations indicate the presence of infection or inflammation, but this finding is nonspecific.
  • Serum bilirubin level elevations indicate obstruction of the CBD; the higher the bilirubin level, the greater the predictive value. CBD stones are present in approximately 60% of patients with serum bilirubin levels greater than 3 mg/dL.
  • Serum amylase and lipase values are elevated in the presence of acute pancreatitis complicating choledocholithiasis.
  • Alkaline phosphatase and gamma-glutamyl transpeptidase levels are elevated in patients with obstructive choledocholithiasis. These test results have a good predictive value for the presence of CBD stones.
  • Prothrombin time may be elevated in patients with prolonged CBD obstruction, secondary to depletion of vitamin K (the absorption of which is bile-dependent).
  • Liver transaminase (serum glutamic-pyruvic transaminase and serum glutamic-oxaloacetic transaminase) levels are elevated in patients with choledocholithiasis complicated by cholangitis, pancreatitis, or both.
  • Blood culture results are positive in 30-60% of patients with cholangitis.

Imaging Studies

• Cholangiography remains the most reliable test for the diagnosis of choledocholithiasis, but its invasive nature, associated morbidity, and cost preclude it from being the screening test of choice. Several diagnostic modalities are available, and these are best divided into preoperative, intraoperative, and postoperative studies. The latter are used for the diagnosis of retained CBD stones.
• Preoperative studies
  • Transabdominal ultrasonography
    • This is a noninvasive, inexpensive, and readily available modality for assessment of the biliary tree. It is usually the first modality used in the diagnosis of patients with biliary-related symptoms.
    • Ultrasonography findings are accurate in the diagnosis of gallbladder stones (97% in elective situations and 80% in presence of acute cholecystitis), but CBD stones are missed frequently (sensitivity 15-40%). The detection of CBD stones is impeded by the presence of gas in the duodenum, possible reflection and refraction of the sound beam by curvature of the duct, and the location of the duct beyond the optimal focal point of the transducer.
    • On the other hand, CBD dilatation is identified accurately, with up to 90% accuracy.
    • The usefulness of ultrasonography findings as a predictor of CBD stones is at best 15-20%.
  • Endoscopic ultrasonography
    • This is the introduction of a high-frequency (7.5-12 MHz) ultrasonic probe advanced into the duodenum under endoscopic guidance. A water-filled balloon is used to provide an acoustic window.
    • Sensitivity and specificity of CBD stone detection are reported in range of 85-100%. This is a significant improvement over the transabdominal route.
    • With endoscopic ultrasonography, the advantage of noninvasiveness is lost, cost is increased, and the services of an experienced endoscopist/ultrasonographer are needed.
  • Computed tomography scan
    • CT scan findings are very accurate in the detection of biliary tree obstruction and ductal dilatation, both intrahepatic and extrahepatic.
    • CT scan has a sensitivity of 75-90% in the detection of CBD stones, which makes it an essential tool in the evaluation of patients with jaundice.
    • It is capable of defining the level of the obstruction and provides information about the surrounding structures, especially the pancreas.
  • Magnetic resonance cholangiopancreatography
    • This technique provides images derived from different magnetic properties of various tissues. Gadolinium is used as a contrast for this test.
    • It is a noninvasive tool with 97% accuracy, 92% sensitivity, and 100% specificity. It is improving with the advent of new sequences in imaging of the CBD.
    • Cost, inconvenience, and limitations (eg, obesity, presence of metal objects, eg, pacemakers) are some of its disadvantages.
  • Cholangiography
    • This remains the criterion standard for the detection of CBD stones.
    • In the past, intravenous cholangiography was the only available method for assessing the biliary tree, but the results had poor accuracy and sensitivity, not to mention major concerns with allergic reactions. Intravenous cholangiography became obsolete with the introduction of endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC).
    • ERCP was introduced in the early 1970s and has become the diagnostic and therapeutic tool of choice in patients with choledocholithiasis. The CBD is cannulated through the ampulla, contrast material is injected, and films are obtained. The experience of the endoscopist is the best predictor of success, which is 90-95% in expert hands. Complications are hyperamylasemia and cholangitis. Prophylactic antibiotics are often recommended, especially in patients with CBD obstruction. In most patients, ERCP is the modality of choice when choledocholithiasis is suggested.
    • PTC may be the modality of choice in patients in whom ERCP is difficult (eg, those with previous gastric surgery or distal obstructing CBD stone or the lack of an experienced endoscopist) and in patients with extensive intrahepatic stone disease and cholangiohepatitis. A long large-bore needle is advanced percutaneously and transhepatically into an intrahepatic duct, and cholangiography is performed. A catheter can be placed in the biliary tree over a guidewire. Uncorrected coagulopathy is a contraindication for PTC, and the normal size of the intrahepatic ducts makes the procedure difficult. Prophylactic antibiotics are recommended to reduce the risk of cholangitis.
• Intraoperative studies
  • Intraoperative cholangiography
    • An area of much debate is the use of routine intraoperative cholangiography (IOC) during a cholecystectomy. This debate has lately gained momentum with the advent of the laparoscopic cholecystectomy.
    • The argument in favor of routine IOC is that it provides accurate information about biliary anatomy and the presence of CBD stones, thus decreasing the incidence of intraoperative bile duct injury.
    • The counterpoint is that the incidence of retained CBD stones is no greater in patients who underwent IOC only when CBD stones were suggested clinically compared with patients in whom it was performed routinely. Also, the risk of bile duct injury is independent of whether an IOC was performed or not. Other drawbacks include the risk and cost of the procedure.
    • IOC is performed by inserting a catheter intraoperatively into the cystic duct, followed by injection of diluted (50%) contrast material to outline the biliary tree. Films are taken and are assessed for the presence of filling defects, the anatomy and caliber of the biliary tree, and the flow of contrast into the duodenum. This procedure can be performed at open or laparoscopic cholecystectomy.
    • IOC findings have a positive predictive value of 60-75% for the detection of CBD stones. The procedure can fail due to (1) inability to cannulate the cystic duct; (2) leakage of contrast during the injection; (3) air bubbles mimicking stones; (4) contrast flowing too quickly into the duodenum, preventing proper filling of the biliary tree; and (5) spasm of the sphincter of Oddi.
  • Intraoperative ultrasonography
    • Special probes are used to visualize the biliary tree. It can be performed using either open or laparoscopic techniques, and results have a positive predictive value of approximately 75%.
    • With the recent introduction of a small high-frequency probe in a 6F sheath, performing intraluminal ultrasonography is now possible.
    • The reported sensitivity is similar to that of IOC. Operator dependency limits the usefulness of this modality.
• Postoperative studies
  • T-tube cholangiography
    • Retained CBD stones are identified in 2-10% of patients after CBD exploration. These are most commonly detected upon routine T-tube cholangiography performed 7-10 days postoperatively.
    • T-tubes are placed following CBD exploration to help in the diagnosis and management of retained stones.
    • If no obstruction is identified on the cholangiogram findings, the tube is clamped and left in place for 6 weeks. The cholangiogram is repeated after 6 weeks (small stones may pass spontaneously), and any retained stones are removed percutaneously.
  • ERCP: After a cholecystectomy, ERCP is the modality of choice to aid in the diagnosis and treatment of retained stones that were undetected or were left behind to be dealt with endoscopically.
  • PTC: This is used in patients with retained intrahepatic stones or in patients with gastric surgery, in whom ERCP is more difficult to perform.

Procedures

• Choledochoscopy: Choledochoscopy can be performed using either open or laparoscopic techniques. Small, flexible choledochoscopes are introduced through an open CBD or cystic duct. This enables direct visualization and extraction of CBD stones. Sensitivity for detection approaches 100% in expert hands. Choledochoscopy can be performed postoperatively through the tract of a T-tube 6 weeks after the T-tube was placed.
• Endoscopic sphincterotomy: This procedure can be performed preoperatively or postoperatively for CBD stones. Usually, stones smaller than 1 cm pass spontaneously within a few days of the sphincterotomy. For extraction of larger stones, a basket or a balloon catheter is required. Endoscopic sphincterotomy is contraindicated in patients with coagulopathy and usually in patients with a long distal CBD.

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