Is this patient's presentation consistent with gallstone pancreatitis?

Diagnosing Gallstone Pancreatitis

If your patient presents with acute pancreatitis and has gallstones on imaging, this is gallstone pancreatitis until proven otherwise—gallstones account for approximately 50% of all acute pancreatitis cases. 1, 2

Key Diagnostic Features

Clinical Presentation

• Epigastric or right upper quadrant pain is the hallmark symptom 1
• Pain may be associated with jaundice and/or fever 1
• Nausea and vomiting are common 3

Laboratory Findings

• Serum amylase elevation ≥3 times the upper limit of normal strongly suggests pancreatitis 4
• Serum amylase >1000 IU/L is particularly characteristic of gallstone pancreatitis 4
• ALT elevation is the most predictive liver function test: elevated ALT occurs in 90% of patients with acute cholecystitis and common bile duct stones (CBDS) 1
• Bilirubin >1.8 mg/dL is a strong predictor of CBDS 1
• However, elevated liver function tests alone are insufficient to diagnose CBDS—they have a positive predictive value of only 15% 1

Imaging Findings

• Transabdominal ultrasound should be performed in all patients to identify gallstones and assess for CBDS 1
• Direct visualization of a stone in the common bile duct on ultrasound is highly specific for CBDS 1
• Common bile duct diameter >6 mm (with gallbladder in situ) is a strong predictor of CBDS 1
• CT scan can confirm pancreatitis and assess for complications, though ultrasound is preferred for initial biliary evaluation 3, 4

Risk Stratification for Common Bile Duct Stones

Use the modified ASGE classification to determine if your patient needs further workup for CBDS: 1

High Risk (requires immediate ERCP)

• Stone visualized in the CBD on ultrasound 1
• Ascending cholangitis (fever, jaundice, right upper quadrant pain) 1

Intermediate Risk (requires MRCP, EUS, or intraoperative evaluation)

• CBD diameter >6 mm with bilirubin 1.8-4 mg/dL 1
• Bilirubin >4 mg/dL without visualized stone 1
• Clinical gallstone pancreatitis (this is your patient) 1
• Age >55 years 1
• Abnormal liver biochemical tests other than bilirubin 1

Low Risk (proceed to cholecystectomy without further biliary imaging)

• No predictors present 1

Diagnostic Algorithm for Your Patient

1. Confirm pancreatitis: Check serum amylase/lipase (≥3× normal) 4

2. Identify gallstones: Perform transabdominal ultrasound 1

3. Assess for CBDS: Check liver function tests (ALT, AST, bilirubin, alkaline phosphatase, GGT) and measure CBD diameter on ultrasound 1

4. Stratify risk using the criteria above 1

5. For intermediate-risk patients (which includes clinical gallstone pancreatitis): Obtain MRCP or EUS before cholecystectomy to avoid unnecessary ERCP 1

   • Both MRCP and EUS have excellent diagnostic accuracy (sensitivity 93-95%, specificity 96-97%) 1
   • Choice depends on local availability and expertise 1

Common Pitfalls to Avoid

• Do not rely solely on elevated liver function tests to diagnose CBDS—up to 50% of patients with acute cholecystitis have elevated LFTs without CBDS 1
• Do not assume CBD dilation alone indicates CBDS—only 39% of patients with CBD >10 mm actually have stones 1
• Do not perform ERCP in all patients with gallstone pancreatitis—reserve it for high-risk patients or those with confirmed CBDS on secondary imaging 1
• Do not delay cholecystectomy beyond 2 weeks in mild pancreatitis, as this dramatically increases recurrent biliary event rates 1, 5, 6