Primary Biliary Stones

Primary common bile duct (CBD) stones form in the bile ducts de novo, without gallbladder origin, and are typically soft brown pigment stones.

• Account for about 5% of CBD stones in Western countries, and up to 50% in East Asia and Southeast Asia (recurrent pyogenic cholangitis).
• Mechanism: biliary stasis and bacterial infection (Escherichia coli, Klebsiella) with beta glucuronidase deconjugating bilirubin to form calcium bilirubinate.
• Risk factors: biliary strictures, duodenal diverticula, choledochal cysts, sclerosing cholangitis, parasitic infestation (Clonorchis, Ascaris, Opisthorchis), prior biliary surgery, bile duct dilatation, sphincter of Oddi dysfunction, foreign bodies (stents, surgical clips).
• Recurrence common (up to 25% over 5 years).
• Complications: cholangitis, hepatic abscess, secondary biliary cirrhosis, pancreatitis.

• Biliary colic, jaundice, fever (Charcot triad), pruritus, dark urine.
• Recurrent cholangitis, especially in patients after cholecystectomy.
• Suppurative cholangitis (Reynolds pentad): hypotension, confusion.
• History of biliary surgery, stents, or travel to endemic regions.

• Liver tests: cholestatic pattern, raised bilirubin; white cells, CRP, blood cultures.
• Ultrasound: dilated bile duct, echogenic foci; low sensitivity for CBD stones (50 to 60%).
• MRCP or endoscopic ultrasound (sensitivity over 90%) for CBD stones and strictures.
• ERCP as therapeutic step. CT for intrahepatic stones and abscess.
• Identify predisposing factors: biliary strictures, anomalies, parasites (stool ova, serology), duodenal diverticulum.

• Cholangitis: resuscitation, antibiotics (ceftriaxone 2 g daily plus metronidazole 500 mg three times daily; piperacillin tazobactam 4.5 g every 6 hours for severe disease), urgent biliary drainage within 24 to 48 hours (earlier in septic shock).
• ERCP with endoscopic sphincterotomy and stone extraction (balloon or basket); mechanical or laser lithotripsy for large stones; large balloon dilatation after sphincterotomy.
• Temporary biliary stent for impacted stones; stent exchange; percutaneous transhepatic drainage if ERCP fails.
• Surgical bile duct exploration with biliary enteric drainage (choledochoduodenostomy or hepaticojejunostomy) for recurrent stones with strictures, large dilated ducts or failed endoscopy.
• Antibiotic prophylaxis at ERCP (ciprofloxacin 500 mg or ceftriaxone 1 g).
• Treat parasitic infection: praziquantel 25 mg/kg three times daily for 2 days (clonorchiasis), albendazole 400 mg for ascariasis.
• Ursodeoxycholic acid is not effective for brown pigment stones.
• Long term surveillance for recurrence.