What is the initial workup for a patient presenting with right upper quadrant (RUQ) pain?

Initial Workup for Right Upper Quadrant (RUQ) Pain

Ultrasonography of the abdomen should be the first-line imaging test for patients presenting with right upper quadrant pain. 1

Diagnostic Approach

Step 1: Clinical Assessment

• Evaluate for specific symptoms:
  • Timing and character of pain (colicky vs. constant)
  • Radiation to shoulder or back
  • Associated symptoms (fever, nausea, vomiting, jaundice)
• Physical examination:
  • Murphy's sign (pain on deep inspiration during RUQ palpation)
  • Presence of jaundice
  • Abdominal tenderness and guarding
  • Hepatomegaly

Step 2: Laboratory Testing

• Complete blood count (CBC) to assess for leukocytosis
• Liver function tests:
  • Transaminases (ALT, AST)
  • Alkaline phosphatase
  • Bilirubin (direct and indirect)
• Pancreatic enzymes (amylase, lipase)
• For women of reproductive age: β-hCG to rule out pregnancy 1

Step 3: Imaging

1. Abdominal Ultrasonography:

   • Highest rated (9/9) on ACR Appropriateness Criteria for RUQ pain 1
   • Advantages:
     • No radiation exposure
     • Highly accurate (96%) for gallstone detection 1
     • Can identify other potential causes of pain 1
     • Cost-effective and readily available 2, 3
     • Allows dynamic assessment during respiration

2. Secondary Imaging (if ultrasonography is inconclusive):

   • Cholescintigraphy (HIDA scan):

     • Consider when ultrasound is equivocal but clinical suspicion for acute cholecystitis remains high
     • Higher sensitivity (97%) and specificity (90%) for acute cholecystitis than ultrasound 1
     • Particularly useful for functional gallbladder assessment

   • CT with contrast:

     • Appropriate when ultrasound findings are equivocal
     • Better for detecting complications of cholecystitis (gangrene, perforation, hemorrhage) 1
     • Can identify non-biliary causes of RUQ pain

   • MRI/MRCP:

     • Consider for patients with equivocal ultrasound findings
     • Useful for visualizing hepatic and biliary abnormalities not characterized on ultrasound 1
     • No radiation exposure

Common Diagnostic Findings

Biliary Pathology

• Cholelithiasis: Echogenic foci with posterior acoustic shadowing on ultrasound
• Acute cholecystitis: Gallbladder wall thickening, pericholecystic fluid, sonographic Murphy's sign
• Biliary obstruction: Dilated bile ducts

Non-Biliary Causes

• Hepatic (abscess, hepatitis, mass)
• Pancreatic (pancreatitis, mass)
• Renal (pyelonephritis, stone)
• Pulmonary (pneumonia, empyema)
• Vascular (hepatic vein thrombosis)

Pitfalls to Avoid

1. Premature closure on gallbladder pathology:

   • Over one-third of patients initially thought to have acute cholecystitis actually have RUQ pain from other causes 2
   • Consider non-biliary etiologies when initial workup is negative 4

2. Relying solely on laboratory values:

   • Normal liver function tests do not exclude biliary disease
   • Elevated alkaline phosphatase may be seen in non-hepatobiliary conditions 4

3. Overlooking referred pain:

   • Thoracic pathology (pneumonia, empyema) can present as RUQ pain 4
   • Consider thoracic imaging if abdominal workup is negative

4. Limitations of ultrasound:

   • Operator-dependent technique
   • Limited visualization in obese patients
   • May be affected by bowel gas

By following this algorithmic approach with ultrasound as the initial imaging modality, clinicians can efficiently diagnose the cause of RUQ pain and implement appropriate management strategies, ultimately improving patient outcomes by reducing time to diagnosis and avoiding unnecessary radiation exposure 1, 2.