Choledocholithiasis

Choledocholithiasis refers to the presence of gallstones in the common bile duct. Characteristic clinical features include right upper quadrant pain and signs of extrahepatic cholestasis. Initial diagnostic evaluation includes an ultrasound and routine laboratory studies, and based on the diagnostic likelihood, confirmatory imaging may involve an endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP), or endoscopic ultrasound (EUS). Treatment consists of stone removal (endoscopically or surgically) and preventing recurrence (e.g., via laparoscopic cholecystectomy).

See also “Cholelithiasis”, “Acute cholecystitis”, and “Acute cholangitis.”

• Sex: ♀ > ♂
• Prevalence: ∼ 5–20% of patients who undergo cholecystectomy have choledocholithiasis at the time of surgery
• Peak incidence: > 40 years

References: ^[1][2]

Epidemiological data refers to the US, unless otherwise specified.

• Secondary choledocholithiasis (most common): cholelithiasis → passage of gallstones into the common bile duct → common bile duct obstruction → spasm of the biliary tracts
  • Risk factor: a history of cholelithiasis
• Primary choledocholithiasis (less common): conditions predisposing to bile stasis → intraductal stone formation
  • Risk factors:
    • Cystic fibrosis
    • Prolonged total parenteral nutrition
• Postcholecystectomy choledocholithiasis ^[3][4][5]
  • Residual choledocholithiasis: CBD stones missed during cholecystectomy; typically becomes symptomatic within 3 years of surgery
  • Recurrent choledocholithiasis: CBD stones that developed after cholecystectomy, typically detected after 3 years of surgery
    • Risk factors for recurrent stones: periampullary duodenal diverticulum, dilated CBD, CBD stricture, chronic cholangitis, sickle cell anemia, and rapid weight loss (e.g., after bariatric surgery)

Symptoms of choledocholithiasis (jaundice, RUQ pain, abnormal LFT) in postcholecystectomy patients may be due to recurrent or residual choledocholithiasis but also due to postinterventional biliary strictures or sphincter of Oddi dysfunction. ^[6]

• RUQ pain
  • More severe and prolonged (may last > 6 hours) than in cholelithiasis
  • Postprandial
  • May radiate to the epigastrium, right shoulder, and back (referred pain)
• Nausea, vomiting, anorexia
• Signs of extrahepatic cholestasis (e.g., jaundice, pale stool, dark urine, pruritus) may be present
• Features of complications: See ''Clinical features'' in acute pancreatitis, acute cholecystitis, and acute cholangitis. ^[5]

Evaluation for choledocholithiasis should be performed in all patients with confirmed symptomatic cholelithiasis or in patients presenting with RUQ pain and/or jaundice.

Approach ^[6][7]

• Initial evaluation: Liver function tests (LFTs) and RUQ ultrasound are the preferred first-line diagnostic tests.
• Determine the need for confirmatory imaging based on predictors of choledocholithiasis.
• See also “Diagnostic workup of acute abdominal pain.”

Initial evaluation

Laboratory studies

• LFTs
  • Characteristic findings: evidence of cholestasis, i.e., ↑ ALP, ↑ GGT, ↑ total and ↑ direct bilirubin ^[8][9][10]
  • Predictive value: high negative predictive value (∼ 97%) ^[6]
• Tests to rule out related biliary comorbidities
  • CBC: Leukocytosis is seen in cholecystitis or cholangitis.
  • Amylase, lipase: elevated in biliary pancreatitis
  • See also “Diagnostics” in cholecystitis, cholangitis, and pancreatitis.

Initial imaging ^[6][11]

Transabdominal RUQ ultrasound

• Indications: preferred first-line imaging modality in patients presenting with RUQ pain and/or jaundice ^[11][12]
• Supportive findings
  • Dilated common bile duct (CBD): Normal CBD diameter varies according to patient age and whether the gallbladder is intact or has been surgically removed. ^[6]
    • Gallbladder in situ, age < 50 years: CBD diameter > 6 mm ^[6]
    • Gallbladder in situ, age > 50 years: CBD diameter > 8 mm ^[13]
    • Postcholecystectomy patients: CBD diameter > 10 mm ^[13]
  • Intrahepatic biliary dilatation may be seen.
  • Visualization of an occluding CBD stone ^[6]
  • Stone(s) within the gallbladder (see ''RUQ transabdominal ultrasound'' in cholelithiasis). ^[6]
• Predictive value: high negative predictive value (∼ 95%) ^[6]

CT abdomen with IV contrast

CT is not routinely recommended if there is a strong suspicion for choledocholithiasis.

• Supportive findings
  • Dilated CBD with/without dilation of the intrahepatic biliary tree
  • Target sign: concentric rings formed by a central hypodense stone surrounded by a rim of iso/hyperdense bile ^[14]
  • Calcium-containing stones may be visualized within the CBD (only 15–20 % stones). ^[15]

Risk stratification ^[6]

Neither LFTs; nor transabdominal ultrasound are confirmatory tests for choledocholithiasis. The presence and strength of predictor(s) aid the risk stratification (likelihood estimation) of choledocholithiasis, which determines the choice of confirmatory imaging.

Confirmatory imaging and further management ^[6][7][16]

Based on the patient's likelihood of choledocholithiasis, the choice of confirmatory imaging modalities differs.

• High likelihood of choledocholithiasis: ERCP
• Intermediate likelihood of choledocholithiasis: MRCP or EUS, based on patient preference, operator expertise, and costs
• Low likelihood of choledocholithiasis: Confirmatory imaging is not routinely required.
• In postcholecystectomy patients, consider MRCP or EUS to evaluate for suspected residual or recurrent choledocholithiasis. ^[6]

Preoperative endoscopic retrograde cholangiopancreatography (ERCP)

• Indication: preferred confirmatory imaging for patients with a high likelihood of choledocholithiasis
  • Diagnostic and therapeutic
  • Highly sensitive and specific (∼ 95%) ^[17]
• Contraindication (for urgent ERCP): acute biliary pancreatitis without evidence of cholangitis or biliary obstruction ^[6][7]
• Characteristic findings
  • Smooth-walled, well-defined, intraluminal filling defect(s) within the CBD, which may be dilated ^[18][19]
  • Dilation of the intrahepatic biliary tree
  • Cholelithiasis: mobile filling defect(s) within the gallbladder lumen
• Complications ^[20]
  • Post-ERCP pancreatitis: pancreatic inflammation secondary to ERCP
    • Incidence: ∼ 3.5% ^[20]
    • Diagnostic criteria (all of the following) ^[21]
      • New or worsened postinterventional abdominal pain
      • New or prolonged hospitalization (at least 2 days)
      • Serum amylase > 3 times the upper limit, measured > 24 hours after the intervention
    • Prevention: Consider indomethacin in high-risk patients
  • Perforation, hemorrhage (both have an incidence of ∼ 1%)
  • Infection: cholangitis, acute cholecystitis (uncommon)
  • Bile duct injury resulting in bile duct strictures (uncommon)

Magnetic resonance cholangiopancreatography (MRCP)

• Indications
  • Patients with an intermediate likelihood of choledocholithiasis ^[7]
  • Suspected postcholecystectomy choledocholithiasis ^[6]
• Characteristic findings: similar to ERCP findings ^[17]
• Advantages: noninvasive procedure; sensitivity and specificity rates similar to ERCP ^[17]

EUS ^[6][7][17]

• Indication: : alternative to MRCP in patients with an intermediate likelihood of choledocholithiasis or suspected postcholecystectomy choledocholithiasis ^[6][7]
  • Second-line confirmatory imaging modality if MRCP findings are inconclusive
  • Preferred confirmatory imaging modality in patients with acute biliary pancreatitis and suspected choledocholithiasis ^[7]
• Characteristic findings: same as transabdominal ultrasound
• Advantages: highly sensitive and specific ^[6][17]

• Differential diagnosis of jaundice with dilated biliary duct
  • Biliary stricture
  • Pancreatic carcinoma (head of pancreas)
  • Cholangiocarcinoma
  • Mirizzi syndrome
  • Extrinsic compression of the bile duct (e.g., lymphadenopathy at the porta hepatis)
• Differential diagnosis of abdominal pain
  • See ''RUQ'' in differential diagnoses of acute abdominal pain.
  • See differential diagnoses of abdominal pain.
• See also “Overview of biliary disease.”

The differential diagnoses listed here are not exhaustive.

Treatment is recommended in all patients with choledocholithiasis, even if asymptomatic. The mainstay of treatment is the removal of the obstruction. ^[22]

Approach ^[6][7][23]

• Provide supportive therapy for patients with acute symptoms
  • See initial supportive therapy of acute biliary disease for details on analgesics, spasmolytics, and antiemetics.
  • NPO in patients with acute pain
• Identify and manage any complications (e.g., acute pancreatitis, cholangitis, cholecystitis).
• Removal of choledocholithiasis
• Elective cholecystectomy to prevent recurrence

Removal of choledocholithiasis ^[7]

• Choledocholithiasis may be removed endoscopically (ERCP) or surgically (LCBDE).
  • Intraoperative diagnosis
    • Intraoperative CBD exploration (LCBDE) and stone extraction
    • OR postoperative ERCP-guided stone extraction
  • Preoperative or postoperative diagnosis: ERCP-guided stone extraction is preferred.
  • In patients with postcholecystectomy residual or recurrent choledocholithiasis: ERCP with papillotomy is preferred. ^[4][24]
• Lithotripsy may be considered in patients not suited, or unwilling, to undergo endoscopic or surgical stone removal.

ERCP-guided stone extraction

• Indications
  • Confirmed choledocholithiasis ^[7]
  • Cholangitis ^[25]
  • Acute biliary pancreatitis with evidence of persistent choledocholithiasis associated with cholangitis ^[7][26]
• Timing: depends on whether there are complications and the timing of diagnosis
  • Uncomplicated choledocholithiasis: preoperatively or postoperatively, depending on when the diagnosis was confirmed in relation to cholecystectomy
  • Associated cholecystitis: same as that for uncomplicated choledocholithiasis
  • Associated cholangitis: depends on the severity of cholangitis as well as operative and anesthesia risks ^[27][28]
    • Mild/moderate acute cholangitis in low-risk patients: within 24–48 hours of presentation
    • Moderate/severe acute cholangitis or high-risk patients: after resolution of acute symptoms (i.e, after urgent biliary drainage)
    • See “Cholangitis” for further details.
  • Associated acute biliary pancreatitis with cholangitis: within 24 hours of presentation (see “Acute pancreatitis” for further details) ^[26]
• Procedure
  • ERCP in combination with any of the following:
    • Papillotomy (sphincterotomy): the sphincter of Oddi is incised using a cautery → widening of the lumen of the distal CBD → facilitation of stone extraction with a basket or balloon ^[29]
    • Papillary balloon dilation
    • Sphincterotomy and papillary balloon dilation
    • CBD stenting

Laparoscopic bile duct exploration (LBCDE; intraoperative stone extraction) ^[7][29][30]

• Indications
  • An alternative to ERCP-guided stone extraction when surgical expertise is available ^[7][30]
  • Stones not suited to extraction
  • Patients with altered GIT anatomy (e.g., status post-Roux-en-Y surgery) for whom ERCP-guided stone extraction is not feasible
• Procedure: incision is made either on the cystic duct (transcystic approach) or CBD directly (choledochotomy approach) and the stone is either flushed out or manually extracted ^[30]

Lithotripsy ^[7]

• Indications
  • Large choledocholithiasis not suited to extraction via ERCP or surgery
  • Complex bile duct anatomy (e.g., distal CBD stricture) that makes ERCP and LCBDE challenging
  • Persistent choledocholithiasis despite ERCP and LCBDE is not possible

Prevention of recurrence

• Procedure: laparoscopic cholecystectomy
• Indication: : recommended in all patients with choledocholithiasis
• Timing: depends on associated complications
  • Uncomplicated choledocholithiasis: within 72 hours of successful ERCP-guided stone clearance ^[23][31]
  • Mild biliary pancreatitis: during the same hospital admission ^[7][26][32]
  • Cholangitis: within 6 weeks of successful ERCP-guided stone clearance ^[25]
  • Acute cholecystitis (see ''Treatment'' in “Acute cholecystitis” for details) ^[33][34]
    • Early laparoscopic cholecystectomy: patients with low operative and anesthesia risks
    • Delayed laparoscopic cholecystectomy: patients with high operative and anesthesia risks at initial presentation
• Complications: See “Cholecystectomy.”

• NPO
• Consult GI for urgent ERCP and stone removal.
• Consult surgery for same-admission cholecystectomy (and potential laparoscopic bile duct exploration).
• Identify and treat any complications (see “Cholangitis” and “Acute Cholecystitis”)
• Supportive care: See ”Initial supportive therapy of acute biliary disease”.
• IV fluid therapy

• Gallstone ileus: mechanical bowel obstruction due to obstructive gallstones ^[35][36]
  • Pathophysiology: gallbladder perforation or Mirizzi syndrome → biliary-enteric fistula formation (most commonly cholecystoenteric fistula) between the inflamed gallbladder and bowel → gallstones passing down into bowel lumen
    • Sites of obstruction
      • Terminal ileum, at ileocecal valve (most common)
      • Gastric pylorus or duodenum ^[37]
  • Symptoms depend on the site of obstruction.
    • Distal bowel obstruction: features of mechanical bowel obstruction (abdominal pain and distention, nausea, vomiting)
    • Gastroduodenal obstruction (rare): features of gastric outlet obstruction (Bouveret syndrome) ^[37]
  • Diagnosis is based on the Rigler triad: imaging findings of small bowel obstruction, gallstone (most commonly in iliac fossa), and pneumobilia.
  • Treatment ^[35]
    • Initial supportive therapy
      • NPO, IV fluid resuscitation, analgesics, antiemetics, nasogastric tube insertion
      • Empiric antibiotic therapy for intra-abdominal infections
    • Enterolithotomy: emergency surgery to remove the obstructing stone
    • Consider cholecystectomy and closure of the biliary-enteric fistula. ^[35]
• Gallstone pancreatitis
• Acute cholangitis
• Acute cholecystitis
• Biliary stricture
• Pyogenic liver abscess

We list the most important complications. The selection is not exhaustive.

1. Ahmed M, Spataro J, Tolaymat M, et al. Complicated choledocholithiasis more common after cholecystectomy. EC Gastroenterology and Digestive System. 2018 .
2. Buxbaum JL, Abbas Fehmi SM, Sultan S, et al. ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis. Gastrointest Endosc. 2019; 89 (6): p.1075-1105.e15. doi: 10.1016/j.gie.2018.10.001 . | Open in Read by QxMD
3. Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endosc. 2010; 71 (1): p.1-9. doi: 10.1016/j.gie.2009.09.041 . | Open in Read by QxMD
4. Pereira-Limâ JC, Jakobs R, Busnello JV, Benz C, Blaya C, Riemann JF. The role of serum liver enzymes in the diagnosis of choledocholithiasis.. Hepatogastroenterology. 2000; 47 (36): p.1522-5.
5. Kelly NM, Tham T. Abnormal Liver Function Tests in Acute Cholecystitis With and Without Choledocholithiasis. Gastroenterology. 2011; 140 (5): p.S-450. doi: 10.1016/s0016-5085(11)61847-7 . | Open in Read by QxMD
6. Peng WK, Sheikh Z, Paterson-Brown S, Nixon SJ. Role of liver function tests in predicting common bile duct stones in acute calculous cholecystitis.. Br J Surg. 2005; 92 (10): p.1241-7. doi: 10.1002/bjs.4955 . | Open in Read by QxMD
7. American College of Radiology ACR Appropriateness Criteria® Jaundice. https://acsearch.acr.org/docs/69497/Narrative/. Updated: January 1, 2018. Accessed: May 26, 2020.
8. American College of Radiology ACR Appropriateness Criteria® Right Upper Quadrant Pain. https://acsearch.acr.org/docs/69474/Narrative/. Updated: January 1, 2018. Accessed: August 28, 2019.
9. Senturk S, Miroglu TC, Bilici A, et al. Diameters of the common bile duct in adults and postcholecystectomy patients: a study with 64-slice CT.. Eur J Radiol. 2012; 81 (1): p.39-42. doi: 10.1016/j.ejrad.2010.11.007 . | Open in Read by QxMD
10. Petrescu I, Bratu AM, Petrescu S, Popa BV, Cristian D, Burcos T. CT vs. MRCP in choledocholithiasis jaundice.. Journal of medicine and life. 2015; 8 (2): p.226-31.
11. Feldman M, Friedman LS, Brandt LJ. Sleisenger and Fordtran's Gastrointestinal and Liver Disease- 2 Volume Set. Elsevier ; 2020
12. Miller FH, Hwang CM, Gabriel H, Goodhartz LA, Omar AJ, Parsons WG. Contrast-Enhanced Helical CT of Choledocholithiasis. American Journal of Roentgenology. 2003; 181 (1): p.125-130. doi: 10.2214/ajr.181.1.1810125 . | Open in Read by QxMD
13. Lee TY. Optimal Evaluation of Suspected Choledocholithiasis: Does This Patient Really Have Choledocholithiasis?. Clinical endoscopy. 2017; 50 (5): p.415-416. doi: 10.5946/ce.2017.146 . | Open in Read by QxMD
14. Sahani DV, Samir AE. Abdominal Imaging. Elsevier Health Sciences ; 2016
15. Harisinghani MM, Chen JW, Weissleder R. Primer of Diagnostic Imaging. Elsevier ; 2018
16. Anderson MA, Fisher L, Jain R, et al. Complications of ERCP. Gastrointest Endosc. 2012; 75 (3): p.467-473. doi: 10.1016/j.gie.2011.07.010 . | Open in Read by QxMD
17. Thaker AM, Mosko JD, Berzin TM. Post-endoscopic retrograde cholangiopancreatography pancreatitis.. Gastroenterology report. 2015; 3 (1): p.32-40. doi: 10.1093/gastro/gou083 . | Open in Read by QxMD
18. Gurusamy KS, Giljaca V, Takwoingi Y, et al. Endoscopic retrograde cholangiopancreatography versus intraoperative cholangiography for diagnosis of common bile duct stones. Cochrane Database of Systematic Reviews. 2015 . doi: 10.1002/14651858.cd010339.pub2 . | Open in Read by QxMD
19. Tazuma S, Unno M, Igarashi Y, et al. Evidence-based clinical practice guidelines for cholelithiasis 2016. J Gastroenterol. 2016; 52 (3): p.276-300. doi: 10.1007/s00535-016-1289-7 . | Open in Read by QxMD
20. European Association for the Study of the Liver (EASL). EASL Clinical Practice Guidelines on the prevention, diagnosis and treatment of gallstones.. J Hepatol. 2016; 65 (1): p.146-181. doi: 10.1016/j.jhep.2016.03.005 . | Open in Read by QxMD
21. Oak JH, Paik CN, Chung WC, Lee K-M, Yang JM. Risk Factors for Recurrence of Symptomatic Common Bile Duct Stones after Cholecystectomy. Gastroenterology Research and Practice. 2012; 2012 : p.1-6. doi: 10.1155/2012/417821 . | Open in Read by QxMD
22. Komarowska M, Snarska J, Troska P, Suszkiewicz R. Recurrent residual choledocholithiasis after cholecystectomy – endoscopic exploration of bile ducts performed 6 times. Polish Annals of Medicine. 2011; 18 (1): p.118-124. doi: 10.1016/s1230-8013(11)70030-3 . | Open in Read by QxMD
23. Li VK, Yum JL, Yeung YP. Optimal timing of elective laparoscopic cholecystectomy after acute cholangitis and subsequent clearance of choledocholithiasis. Am J Surg. 2010; 200 (4): p.483-488. doi: 10.1016/j.amjsurg.2009.11.010 . | Open in Read by QxMD
24. Tenner S, Baillie J, Dewitt J, Vege SS. American College of Gastroenterology guideline: management of acute pancreatitis. Am J Gastroenterol. 2013; 108 (9): p.1400-1415. doi: 10.1038/ajg.2013.218 . | Open in Read by QxMD
25. Kiriyama S, Kozaka K, Takada T, et al. Tokyo Guidelines 2018: diagnostic criteria and severity grading of acute cholangitis (with videos). Journal of Hepato-Biliary-Pancreatic Sciences. 2018; 25 (1): p.17-30. doi: 10.1002/jhbp.512 . | Open in Read by QxMD
26. Miura F, Okamoto K, Takada T, et al. Tokyo Guidelines 2018: initial management of acute biliary infection and flowchart for acute cholangitis. Journal of Hepato-Biliary-Pancreatic Sciences. 2018; 25 (1): p.31-40. doi: 10.1002/jhbp.509 . | Open in Read by QxMD
27. Molvar C, Glaenzer B. Choledocholithiasis: Evaluation, Treatment, and Outcomes.. Seminars in interventional radiology. 2016; 33 (4): p.268-276. doi: 10.1055/s-0036-1592329 . | Open in Read by QxMD
28. Memon MA, Hassaballa H, Memon MI. Laparoscopic common bile duct exploration: the past, the present, and the future.. Am J Surg. 2000; 179 (4): p.309-15. doi: 10.1016/s0002-9610(00)00346-9 . | Open in Read by QxMD
29. Huang RJ, Barakat MT, Girotra M, Banerjee S. Practice Patterns for Cholecystectomy After Endoscopic Retrograde Cholangiopancreatography for Patients With Choledocholithiasis. Gastroenterology. 2017; 153 (3): p.762-771.e2. doi: 10.1053/j.gastro.2017.05.048 . | Open in Read by QxMD
30. Crockett et al. American Gastroenterological Association Institute Guideline on Initial Management of Acute Pancreatitis. Gastroenterology. 2018; 154 (4): p.1096-1101. doi: 10.1053/j.gastro.2018.01.032 . | Open in Read by QxMD
31. Schuster KM, Holena DN, Salim A, Savage S, Crandall M. American Association for the Surgery of Trauma emergency general surgery guideline summaries 2018: acute appendicitis, acute cholecystitis, acute diverticulitis, acute pancreatitis, and small bowel obstruction.. Trauma surgery & acute care open. 2019; 4 (1): p.e000281. doi: 10.1136/tsaco-2018-000281 . | Open in Read by QxMD
32. Gutt CN, Encke J, Köninger J, et al. Acute Cholecystitis. Ann Surg. 2013; 258 (3): p.385-393. doi: 10.1097/sla.0b013e3182a1599b . | Open in Read by QxMD
33. Nuño-Guzmán CM, Marín-Contreras ME, Figueroa-Sánchez M, Corona JL. Gallstone ileus, clinical presentation, diagnostic and treatment approach. World J Gastrointest Surg. 2016; 8 (1): p.65. doi: 10.4240/wjgs.v8.i1.65 . | Open in Read by QxMD
34. Abich E, Glotzer D, Murphy E. Gallstone Ileus: An Unlikely Cause of Mechanical Small Bowel Obstruction. Case Reports in Gastroenterology. 2017; 11 (2): p.389-395. doi: 10.1159/000475749 . | Open in Read by QxMD
35. Caldwell KM, Lee SJ, Leggett PL, Bajwa KS, Mehta SS, Shah SK. Bouveret syndrome: current management strategies.. Clinical and experimental gastroenterology. 2018; 11 : p.69-75. doi: 10.2147/CEG.S132069 . | Open in Read by QxMD
36. Stinton LM, Shaffer EA. Epidemiology of gallbladder disease: cholelithiasis and cancer. Gut Liver. 2012; 6 (2): p.172-187. doi: 10.5009/gnl.2012.6.2.172 . | Open in Read by QxMD
37. Chandrasekhara V, Elmunzer BJ, Khashab M, Muthusamy M. Clinical Gastrointestinal Endoscopy. Elsevier ; 2018
38. Ahmed M, Spataro J, Tolaymat M, et al. Prevalence and risk factors for choledocholithiasis after cholecystectomy. American Journal of Gastroenetrology. 2017 .
39. VanderVelde J, Goldberg RF. Clinical Algorithms in General Surgery. Springer, Cham ; 2019
40. Arain MA, Freeman ML. Choledocholithiasis: Clinical manifestations, diagnosis, and management. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/choledocholithiasis-clinical-manifestations-diagnosis-and-management.Last updated: March 13, 2015. Accessed: February 14, 2017.
41. Heuman DM. Gallstones (Cholelithiasis). Gallstones (Cholelithiasis). New York, NY: WebMD. http://emedicine.medscape.com/article/175667-treatment. Updated: April 14, 2016. Accessed: February 14, 2017.
42. Afdhal NH. Epidemiology of and risk factors for gallstones. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/epidemiology-of-and-risk-factors-for-gallstones.Last updated: November 28, 2016. Accessed: March 1, 2017.
43. Gurusamy KS, Giljaca V, Takwoingi Y, et al. Ultrasound versus liver function tests for diagnosis of common bile duct stones.. The Cochrane database of systematic reviews. 2015 : p.CD011548. doi: 10.1002/14651858.CD011548 . | Open in Read by QxMD
44. Manes G, Paspatis G, Aabakken L, et al. Endoscopic management of common bile duct stones: European Society of Gastrointestinal Endoscopy (ESGE) guideline. Endoscopy. 2019; 51 (05): p.472-491. doi: 10.1055/a-0862-0346 . | Open in Read by QxMD