What is the appropriate workup for a patient presenting with yellow skin (jaundice)?

Workup for Yellow Skin (Jaundice)

Begin with initial laboratory testing including total and fractionated bilirubin, complete blood count, liver enzymes (AST, ALT, alkaline phosphatase, GGT), albumin, prothrombin time/INR, followed immediately by abdominal ultrasound as the first-line imaging study. 1, 2, 3

Initial Laboratory Evaluation

The first step is determining whether hyperbilirubinemia is conjugated or unconjugated through fractionated bilirubin testing 2, 3:

• Unconjugated hyperbilirubinemia suggests hemolysis, hematoma resorption, or bilirubin metabolism defects (Gilbert syndrome, Crigler-Najjar syndrome) 1, 4
• Conjugated hyperbilirubinemia indicates hepatocellular disease or biliary obstruction 5, 4

Key laboratory patterns 2, 5:

• Elevated alkaline phosphatase and GGT suggest biliary obstruction rather than hepatocellular injury 2
• AST/ALT elevation is more indicative of hepatocellular injury 2
• Synthetic function tests (albumin, PT/INR) assess severity of liver dysfunction 5, 3

Imaging Algorithm

First-Line: Abdominal Ultrasound

Ultrasound is the recommended initial imaging modality for all patients with jaundice 1, 2:

• Sensitivity of 32-100% and specificity of 71-97% for detecting biliary obstruction 1
• Sensitivity of 65-95% for detecting cirrhosis, with nodular liver surface being the most accurate finding 1
• Limited sensitivity (22.5-75%) for detecting common bile duct stones due to overlying bowel gas 1

If Biliary Obstruction is Confirmed (Dilated Ducts on Ultrasound)

Proceed to either MRCP or contrast-enhanced CT to determine the site and cause of obstruction 1, 6:

MRCP is preferred when 1:

• More detailed biliary tree visualization is needed
• Patient is pregnant
• Hilar obstruction is suspected
• ERCP has failed or patient is too unstable for ERCP
• Suspected primary sclerosing cholangitis or primary biliary cirrhosis 1

Contrast-enhanced CT is preferred when 1:

• Rapid evaluation is needed (scan time <1 minute vs. 30 minutes for MRI) 1
• Suspected malignancy requiring staging (sensitivity 74-96%, specificity 90-94% for obstruction) 1
• Suspected complications like cholangitis, cholecystitis, or pancreatitis 1
• MDCT with 64-slice or higher has >90% sensitivity for biliary obstruction 1

If No Biliary Obstruction on Ultrasound

When ultrasound shows no ductal dilatation but jaundice persists 1:

• Consider MRCP or contrast-enhanced MRI to exclude pathology that ultrasound may miss, including hepatic metastases, biliary strictures/masses, and pancreatic pathology 1
• MRI with MRCP is particularly valuable for detecting early primary sclerosing cholangitis or primary biliary cirrhosis, which can be patchy and missed on liver biopsy 1
• If imaging remains negative, proceed to liver biopsy per American College of Gastroenterology recommendations 1

Common Pitfalls to Avoid

Critical errors in workup 1:

• Do not assume absence of obstruction based solely on normal bile duct caliber—acute obstruction may not show ductal dilatation initially 1
• Do not skip cross-sectional imaging (CT/MRI) when ultrasound shows no ductal dilatation—ultrasound has limited sensitivity for pancreatic masses, small biliary strictures, and hepatic metastases 1
• Do not rely on tumor markers alone (CEA, CA 19-9)—they lack specificity and should not replace imaging 1
• Do not perform ERCP as initial diagnostic test—it carries 4-5% morbidity and 0.4% mortality risk and should be reserved for therapeutic intervention after non-invasive imaging 1

When to Proceed to Invasive Procedures

ERCP is indicated when 1:

• Therapeutic intervention is planned (stone extraction, stent placement)
• High suspicion for choledocholithiasis with dilated CBD
• Malignant obstruction requiring palliation

EUS with FNA is indicated when 1:

• Tissue diagnosis needed for pancreatic or periampullary mass (sensitivity 90.8%, specificity 96.5%) 1
• Small distal CBD stones (<4 mm) suspected but not seen on other imaging 1

Percutaneous transhepatic biliary drainage is reserved for 1:

• Failed ERCP
• Altered anatomy precluding endoscopic access
• Hilar obstructions