What are cholelithiasis (gallstones in the gallbladder) and choledocholithiasis (gallstones in the common bile duct) and what do EGD (Esophagogastroduodenoscopy), ERCP (Endoscopic Retrograde Cholangiopancreatography), and EUS (Endoscopic Ultrasonography) evaluate?

Definitions and Clinical Evaluation of Biliary Stone Disease

Cholelithiasis refers to gallstones in the gallbladder, while choledocholithiasis refers to gallstones in the common bile duct (CBD), which affects approximately 10% of patients with gallstone disease and requires intervention even when asymptomatic due to risks of obstructive jaundice, cholangitis, acute pancreatitis, and potentially secondary biliary cirrhosis. 1

Understanding the Conditions

Cholelithiasis

• Gallstones located within the gallbladder 2
• Often asymptomatic but can cause biliary colic, cholecystitis, or complications when stones migrate 2
• Diagnosed primarily with abdominal ultrasonography 2

Choledocholithiasis

• Gallstones that have migrated into or formed within the common bile duct 1
• Requires intervention even when asymptomatic due to significant complications 1
• Can lead to obstructive jaundice, cholangitis, acute pancreatitis, and secondary biliary cirrhosis 1

What These Procedures Evaluate

When a patient undergoes EGD, ERCP, and EUS together, they are being evaluated for suspected choledocholithiasis (CBD stones), biliary obstruction, pancreatic disease, or malignant biliary/pancreatic obstruction. 3

Specific Indications for Each Procedure:

ERCP (Endoscopic Retrograde Cholangiopancreatography)

• Primary therapeutic procedure for choledocholithiasis with 90% success rate for stone clearance 1, 4
• Evaluates and treats:
  • Cholangitis (infection of bile ducts) 3
  • Gallstone pancreatitis 3
  • Symptomatic pancreatic or biliary disease 3
  • Obstructive jaundice 3
  • Malignant biliary obstruction requiring palliation 3
• Complications include 1-2% risk of pancreatitis, cholangitis, perforation, hemorrhage, increasing to 10% with sphincterotomy 5

EUS (Endoscopic Ultrasound)

• Best diagnostic accuracy for CBD stones with sensitivity 89-95% and specificity 94-97% 5, 4, 6
• Evaluates:
  • Suspected choledocholithiasis, especially small stones missed by other imaging 6
  • Distal biliary tract obstruction 3
  • Pancreatic cysts 3
  • Infected or symptomatic fluid collections 3
  • Tissue diagnosis via fine-needle aspiration for suspected malignancy 3
• Superior to MRCP for detecting small CBD stones, particularly those <5mm or impacted at the distal CBD 6

EGD (Esophagogastroduodenoscopy)

• Evaluates upper gastrointestinal tract including esophagus, stomach, and duodenum 3
• In this context, typically performed as part of:
  • Palliation of luminal obstruction from pancreaticobiliary disease 3
  • Evaluation of ampullary region 7
  • Access route for ERCP 3

Clinical Algorithm for Evaluation

Risk Stratification Approach 5

High-Risk Patients (>50% probability of CBD stones):

• CBD stone visible on ultrasound 5
• Total bilirubin >4 mg/dL 5
• CBD diameter >6 mm with gallbladder present 5
• Proceed directly to ERCP for diagnosis and treatment 5

Moderate-Risk Patients:

• Require confirmatory imaging with either EUS (sensitivity 95%, specificity 97%) or MRCP (sensitivity 93%, specificity 96%) before ERCP 5
• EUS is preferred when available as it can be performed in same session as ERCP, reducing need for multiple procedures and sedations 4

Low-Risk Patients:

• Managed expectantly without invasive procedures 5

Same-Session EUS and ERCP Approach

Performing EUS and ERCP in the same session offers significant clinical benefits including real-time diagnostic information, single sedation, reduced risk of cholangitis/pancreatitis while awaiting ERCP, and shortened hospital stay. 4

Ideal Candidates for Same-Session Approach: 4

• High-risk patients for CBD stones
• Symptomatic post-cholecystectomy patients
• Pregnant women requiring urgent intervention
• Patients unfit for surgery

Important Clinical Pitfalls

• ERCP should not be performed for low-probability choledocholithiasis, especially in women with recurrent pain, normal bilirubin, and no objective signs of biliary disease 7
• 27-67% of ERCPs performed for suspected choledocholithiasis have negative results, highlighting the importance of proper risk stratification 8
• EUS negative for CBD stones has 95.3% negative predictive value, allowing selective exclusion of ERCP and avoiding unnecessary complications 9
• In elderly patients, ERCP complications increase to 19% with 7.9% mortality, requiring careful consideration 1