Pathogenesis
Stones in the bile ducts may be primary (develop in the duct) or secondary (originate in the gallbladder). If they are discovered after cholecystectomy, they may have been overlooked (retained) or may have formed after the surgery (recurrent).
Primary bile duct stones are rare in Western countries. They are more common in the Orient and are often associated with biliary infections and parasitic infestations. They are usually pigment stones.
Secondary bile duct stones
Because 10% to 15% of patients with cholesterol gallstones also have stones in the common bile duct, it is thought that most common bile duct stones in the Western countries originate from the gallbladder. In fact, 95% of patients with ductal stones also have stones in the gallbladder.
Stones found in the bile ducts after cholecystectomy may be retained or may have formed de novo. Bile stasis associated with partial obstruction or marked dilatation of the duct may promote choledocholithiasis. Recurrent stones are often formed from bile pigments.
Diagnosis
Clinical presentation
Choledocholithiasis may present in the following ways:
- Biliary colic-abdominal pain.
- Obstructive jaundice.
- Cholangitis.
- Pancreatitis.
- Hemobilia.
The biliary obstruction caused by cholelithiasis and the ensuing increased biliary pressure and diminished bile flow result in the morbidity associated with duct stones. The rate of progression of the obstruction, its degree, and concomitant bacterial contamination of the biliary tract determine the severity of the syndrome. Thus acute obstruction usually causes colic with or without concomitant pancreatitis; gradual obstruction may present as jaundice. Cholangitis and abscess formation may follow if obstruction is not relieved. Chronic biliary obstruction, if not relieved, may give rise to secondary biliary cirrhosis resulting in hepatic failure and portal hypertension.
Signs and symptoms. The most common complaint is right upper abdominal or epigastric pain, which is usually associated with nausea and vomiting. Jaundice, which may be fluctuating or progressive, is also common. If obstruction is severe, dark urine and pale stools may develop. Fever and chills, if present, will signal cholangitis or abscess formation.
Diagnostic studies
Laboratory studies
Elevation of alkaline phosphatase and bilirubin levels is the hallmark of ductal obstruction. Serum amylase may be elevated without concurrent pancreatitis. Elevation of transaminases (alanine aminotransferase, aspartate aminotransferase) may be seen transiently with passage of a stone. If it persists, along with leukocytosis, cholangitis is suspected.
Ultrasonography is the initial diagnostic test of choice in the workup of gallstone disease. Aside from the presence of stones in the gallbladder, dilatation of the biliary tract secondary to obstruction of the bile ducts is clearly seen on ultrasound. If the obstruction occurs acutely, dilatation may not be present.
In patients who have undergone cholecystectomy, slight dilatation of the common bile duct (up to 0.8 cm) may be acceptable without the presence of distal obstruction.
Biliary scintigraphy using 99mTc-labeled HIDA or PIPIDA may show obstruction of the common bile duct in 85% to 90% of cases. In a positive scan, if the cystic duct is patent, the passage of the radionuclide into the gallbladder and the major ducts but not into the small bowel is noted within 1 to 4 hours.
Computed tomography scan is an excellent method to demonstrate common bile duct stones, especially those with calcium.
Magnetic resonance cholangiopancreatography has excellent sensitivity and specificity in visualizing the common bile duct for stones as well as detecting other structural abnormalities such as ductal dilation, sclerosing cholangitis and cystic abnormalities.
Endoscopic retrograde cholangiopancreatography demonstrates the location of the stone or stones in the bile ducts and is preferred in patients with suspected common bile duct obstruction without intrahepatic ductal dilatation. Endoscopic examination of the upper gastrointestinal tract and the duodenal ampullary orifice helps to rule out pathology in these areas. Endoscopic sphincterotomy has replaced operative sphincteroplasty in patients with retained or recurrent common bile duct stones discovered after cholecystectomy. In most cases, common bile duct stones smaller than 1.5 cm spontaneously pass into the duodenum after endoscopic sphincterotomy.
Stones larger than 1.5 cm can be fragmented and removed with special endoscopic retrograde cholangiopancreatography catheters, baskets, and balloons. This technique can also be used therapeutically in debilitated patients with common bile duct stones and intact gallbladders when cholecystectomy and bile duct exploration are medically contraindicated. If an impacted common bile duct stone is the cause of the pancreatitis, endoscopic removal by sphincterotomy is the preferred immediate mode of therapy. In all cases in which an obstructed common bile duct is manipulated, broad-spectrum intravenous antibiotic coverage must be provided to the patient to prevent sepsis.
Percutaneous transhepatic cholangiography may be used diagnostically and occasionally therapeutically in some patients. If obstruction of the common bile duct and dilatation of the intrahepatic biliary tract has been demonstrated by ultrasound, the location and the nature of the obstruction can be delineated by percutaneous transhepatic cholangiography. Furthermore, it is possible to relieve the obstruction, even if temporarily, by the insertion of a stent, especially in debilitated patients in whom surgery is contraindicated. Dissolution of common bile duct cholesterol stones by infusion of solvents such as monooctonoin with a catheter percutaneously placed above the stone or attempts at dislodging and mobilizing the stone and facilitating its passage into the duodenum or withdrawing it percutaneously may be considered for therapy for such patients. Patients should be treated with intravenous broad-spectrum antibiotics before such attempts.
Treatment
In symptomatic patients presenting with stones in the gallbladder and the common bile duct, the treatment of choice is laparoscopic cholecystectomy and endoscopic stone extraction via endoscopic retrograde cholangiopancreatography pre- or postoperatively. Cholecystectomy and common bile duct exploration are reserved for patients with contraindications to the laparoscopic procedure or who require abdominal exploration. If stones are found in the common bile duct during common bile duct exploration, they should be removed, and a drainage procedure such as a sphincteroplasty or choledochoenterostomy may be performed to allow the passage of any residual stones into the gut. In these instances, a T tube is placed in the common bile duct to decompress the biliary duct and to allow the performance of postoperative cholangiograms.
In approximately 2% of the patients, a residual common bile duct stone is demonstrated on postoperative cholangiograms. These residual stones may be extracted either percutaneously through the T tube or endoscopically by means of endoscopic retrograde cholangiopancreatography. In situ dissolution of cholesterol stones with monooctanoin or methyltert-butyl ether infusion has also been successful in selected patients. If these methods fail, endoscopic sphincterotomy and stone removal or reoperation may be necessary.
Jennifer is a clinical pharmacologist. She helps doctors of all medical specialties choose medications. Jennifer consults about drug dosage, interactions, and side effects.