What is the most appropriate initial investigation for an elderly man with progressive jaundice, deep yellow sclera, dark urine, pale stool, a distended Gallbladder (GB) with stones, and a dilated Common Bile Duct (CBD)?

Diagnostic Approach for Elderly Man with Obstructive Jaundice

Ultrasound (US) is the most appropriate initial investigation for this elderly man with progressive jaundice, deep yellow sclera, dark urine, pale stool, distended gallbladder with stones, and dilated CBD. 1

Rationale for Ultrasound as First-Line Investigation

• Ultrasound is recommended by the American College of Radiology and American College of Gastroenterology as the initial imaging modality for suspected obstructive jaundice 1
• It offers high diagnostic accuracy with:
  • 87% accuracy for detecting gallbladder stones
  • 82% accuracy for detecting common bile duct dilatation
  • 80% accuracy for detecting pancreatic masses 1, 2
• Ultrasound can confirm the obstructive process, localize the site of obstruction, and differentiate between likely benign and malignant causes 1
• It is less costly and provides similar information to CT for initial evaluation 2

Diagnostic Algorithm After Initial Ultrasound

If ultrasound confirms obstruction but is inconclusive about the exact cause:

1. MRCP (Magnetic Resonance Cholangiopancreatography) should be performed next

   • Superior to US for determining both site and cause of obstruction
   • Higher sensitivity (77-88%) for detecting ductal calculi 1

2. CT with contrast may be useful if malignancy is suspected

   • High sensitivity (74-96%) and specificity (90-94%) for biliary obstruction
   • Limited sensitivity for non-calcified gallstones 1

3. ERCP (Endoscopic Retrograde Cholangiopancreatography) should be reserved primarily for therapeutic intervention after diagnosis is established

   • 4-5.2% risk of major complications (pancreatitis, cholangitis, hemorrhage, perforation)
   • Should not be used as a first-line diagnostic tool 1

Important Clinical Considerations

• In this case, the patient already has clinical signs strongly suggestive of obstructive jaundice (progressive jaundice, deep yellow sclera, dark urine, pale stool)
• The presence of gallbladder stones and dilated CBD on examination suggests choledocholithiasis as a likely cause
• Ultrasound can confirm these findings and guide subsequent management

Limitations to Consider

• False-negative US findings can occur due to:
  • Inability to visualize the extrahepatic biliary tree
  • Absence of biliary dilation in acute obstruction
  • Limited sensitivity (22.5-75%) for detecting distal CBD stones 1
• EUS has excellent diagnostic accuracy (95.9%) for determining the cause of suspected obstruction, particularly for ampullary and pancreatic cancer (100% accuracy) 1
• However, EUS has limitations including a limited field of view and operator-dependent results 1

Answer to Multiple Choice Question

The answer is C. US (Ultrasound) as the most appropriate initial investigation for this patient.