What are the potential causes and next steps for a patient with right upper quadrant pain, orange diarrhea, and a general feeling of being unwell, who has a history of cholecystectomy (surgical removal of the gallbladder) and currently has no gallbladder?

Post-Cholecystectomy Right Upper Quadrant Pain with Orange Diarrhea

Immediate Diagnostic Approach

Start with right upper quadrant ultrasound immediately to evaluate for retained common bile duct stones, bile duct injury, or biloma, as this presentation is highly suspicious for choledocholithiasis, which occurs in 5-15% of post-cholecystectomy patients. 1

Primary Differential Diagnoses to Consider

The combination of RUQ pain, orange diarrhea, and general malaise in a post-cholecystectomy patient suggests:

• Choledocholithiasis (retained CBD stones) - The colicky RUQ pain pattern is the classic presentation, occurring in 5-15% of post-cholecystectomy patients 1
• Bile acid diarrhea - The orange diarrhea specifically suggests bile salt malabsorption, which can occur after cholecystectomy when bile continuously drips into the intestine rather than being stored and released with meals 1
• Bile duct injury or stricture - Can present with intermittent obstruction and similar symptoms as a complication of the prior surgery 1
• Sphincter of Oddi dysfunction - Can cause recurrent RUQ pain mimicking chronic cholecystitis in post-cholecystectomy patients 2, 1

Step-by-Step Diagnostic Algorithm

Step 1: Right Upper Quadrant Ultrasound (First-Line)

Order RUQ ultrasound rated 9/9 (usually appropriate) by the American College of Radiology for detecting common bile duct dilatation, visualizing bile duct stones, and identifying complications like biloma or bile duct injury. 1

Ultrasound provides:

• 96% accuracy for detecting stones 2
• Assessment of common bile duct dilatation 1
• Evaluation for biloma or bile duct injury 1
• Visualization of intrahepatic and extrahepatic bile ducts 2

Critical caveat: Ultrasound has limitations for visualizing the distal common bile duct due to overlying bowel gas, with sensitivities for CBD stone detection ranging from only 22.5% to 75% 3

Step 2: MRCP (If Ultrasound Negative or Equivocal)

If ultrasound is negative or equivocal, proceed directly to MRCP, which has 85-100% sensitivity and 90% specificity for detecting choledocholithiasis and is superior to CT for assessing suspected biliary sources of RUQ pain. 1, 3

MRCP advantages include:

• Superior visualization of the cystic duct remnant and common bile duct 1
• Excellent detection of bile duct injuries, strictures, and anatomic abnormalities 1
• Comprehensive evaluation of the entire hepatobiliary system 1
• Identifies the level and cause of biliary obstruction with 91-100% accuracy 3

Step 3: Consider Hepatobiliary Scintigraphy (HIDA Scan)

If MRCP is negative and sphincter of Oddi dysfunction or biliary dyskinesia is suspected, consider cholecystokinin-augmented cholescintigraphy, though evidence for its utility in chronic post-cholecystectomy pain is limited. 1

HIDA scan can evaluate:

• Low-grade, partial, or intermittent biliary obstruction presenting with recurrent RUQ pain 2
• Sphincter of Oddi dysfunction without the risk of pancreatitis associated with manometry 2

Important limitation: The diagnostic value of cholescintigraphy in patients with acalculous RUQ pain is low, as this entity represents a variety of processes including inflammation, gallbladder dysmotility, and irritable bowel syndrome 4

Step 4: CT with IV Contrast (Reserved for Specific Scenarios)

Reserve CT with IV contrast only for critically ill patients, suspected complications beyond simple biliary pathology, or when MRCP is contraindicated or unavailable. 1, 3

CT has limited value because:

• Only ~75% sensitivity for detecting gallstones 1
• Many gallstones are not radiopaque (up to 80% are noncalcified) 3
• Exposes patients to unnecessary radiation without clear diagnostic advantage 1

Addressing the Orange Diarrhea

The orange diarrhea component suggests bile acid malabsorption, which occurs when:

• Continuous bile flow into the intestine (without gallbladder storage) overwhelms the terminal ileum's reabsorption capacity 1
• Excess bile acids reach the colon, causing secretory diarrhea with characteristic orange/yellow coloration 1

This symptom supports a biliary etiology and makes choledocholithiasis or sphincter of Oddi dysfunction more likely. 1

Critical Pitfalls to Avoid

• Do not order HIDA scan as the primary test for elevated LFTs and RUQ pain - It does not provide anatomic visualization of the bile ducts that you need 3
• Do not skip ultrasound and go straight to advanced imaging - Ultrasound remains the essential first step with high diagnostic yield and no radiation 2
• Do not order CT as initial imaging - It is inferior to ultrasound for gallbladder pathology and inferior to MRCP for biliary tree evaluation 1, 5
• Do not proceed to ERCP without confirming biliary obstruction - ERCP is therapeutic, not diagnostic, and carries risks of pancreatitis and perforation 3

When to Consider Non-Biliary Causes

After several negative biliary imaging tests, broaden the differential to include referred pain from thoracic pathology, as right upper quadrant pain can result from paraspinal abscess, empyema, or other non-abdominal sources. 6