What to do for a patient presenting with right upper quadrant (RUQ) pain?

Right Upper Quadrant Pain: Initial Diagnostic Approach

Start with ultrasound as your first-line imaging modality for any patient presenting with right upper quadrant (RUQ) pain. 1, 2

Initial Imaging Strategy

Ultrasound (US) is the primary and most appropriate initial imaging test for RUQ pain evaluation, regardless of whether biliary disease is your leading clinical suspicion. 1, 2 This recommendation is based on multiple advantages:

• Rapid deployment without removing the patient from the resuscitation area 1
• High sensitivity and specificity for gallstones, biliary dilatation, and acute inflammatory disease 3
• No radiation exposure or contrast administration required 1
• Evaluates multiple organ systems simultaneously (liver, gallbladder, bile ducts, pancreas, kidneys, vessels) 4
• Cost-effective with immediate availability 2

Key US Findings to Assess

When performing or interpreting RUQ ultrasound, specifically evaluate for: 1

• Gallstones (cholelithiasis)
• Gallbladder wall thickening (>3mm suggests cholecystitis)
• Pericholecystic fluid
• Sonographic Murphy's sign (focal tenderness over gallbladder with probe pressure)
• Bile duct dilatation (common bile duct >6mm)
• Intraluminal debris, membranes, or gas (suggests complicated cholecystitis)
• Alternative diagnoses: hepatic lesions, renal pathology, pancreatic abnormalities 4

A normal gallbladder wall appearance makes acute gallbladder pathology very unlikely. 1

When to Escalate Beyond Ultrasound

If US is Equivocal or Complicated Cholecystitis Suspected

Order CT abdomen with IV contrast when: 1

• US findings are equivocal for acute cholecystitis
• Complications are suspected (emphysematous, gangrenous, hemorrhagic, or perforated cholecystitis) 1
• Alternative diagnoses need exclusion 1

CT has a negative predictive value approaching 90% for acute cholecystitis and can detect complications including gangrene, gas formation, intraluminal hemorrhage, and perforation. 1 The key advantage of IV contrast is visualization of adjacent liver parenchymal hyperemia (an early finding in acute cholecystitis) and abnormal gallbladder wall enhancement. 1

Avoid CT without IV contrast in this setting—it misses critical findings like wall enhancement and liver hyperemia. 1

If Acute Cholecystitis Diagnosis Remains Uncertain

Consider Tc-99m cholescintigraphy (HIDA scan) when: 1

• US and clinical findings are discordant
• You need definitive confirmation of cystic duct obstruction
• Gallbladder nonvisualization with delayed imaging or morphine augmentation is highly accurate for acute cholecystitis 1

Important caveat: Although cholescintigraphy has higher sensitivity and specificity than US for acute cholecystitis, US remains first-line due to shorter study time, morphologic evaluation, and ability to identify alternative diagnoses. 1

Special Populations

In critically ill patients, be aware that gallbladder abnormalities are common even without acute cholecystitis, limiting US usefulness. 1

For functional gallbladder disorders (biliary colic with normal imaging), consider HIDA scan with cholecystokinin stimulation to measure gallbladder ejection fraction: 5

• GBEF <35% suggests biliary dyskinesia (hypokinesia)
• GBEF >80% suggests biliary hyperkinesia (rare but treatable cause)

Alternative Diagnoses to Consider

Over one-third of patients with RUQ pain do not have acute cholecystitis. 3, 4 US can identify: 4

• Hepatic: abscess, tumor, hepatitis
• Pancreatic: pancreatitis, mass
• Renal: pyelonephritis, nephrolithiasis
• Vascular: portal vein thrombosis, Budd-Chiari syndrome
• Gastrointestinal: peptic ulcer disease, hepatic flexure colitis
• Thoracic: pneumonia, pleural effusion

Common Pitfalls to Avoid

• Don't skip US and go straight to CT—you'll miss the opportunity for rapid, radiation-free diagnosis and increase costs unnecessarily 2, 3
• Don't order CT without IV contrast for suspected cholecystitis—critical findings require contrast enhancement 1
• Don't assume normal US excludes all pathology—if clinical suspicion remains high, proceed to cholescintigraphy or CT 1
• Don't forget to assess for gallbladder ejection fraction abnormalities in patients with recurrent biliary colic and normal baseline imaging 5