A 35-year-old woman presents with 2 weeks of jaundice, pruritus, and pale stools. Serum bilirubin is 6.8 mg/dL (predominantly conjugated), ALT 580 U/L, AST 420 U/L, ALP 280 U/L, and GGT 320 U/L. Abdominal ultrasound shows dilated intrahepatic and extrahepatic bile ducts with a 1.5 cm stone in the common bile duct. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has **obstructive (post-hepatic) jaundice** from choledocholithiasis. The predominantly conjugated hyperbilirubinemia, marked elevation of transaminases and ALP (cholestatic pattern), pale stools (acholia), pruritus, and imaging confirmation of a CBD stone with ductal dilatation are diagnostic. ## Key Point: **ERCP with endoscopic sphincterotomy is the gold-standard treatment for choledocholithiasis.** MRCP is the preferred imaging modality to confirm the diagnosis before ERCP in most centres; it has >90% sensitivity and specificity for CBD stones and avoids radiation and pancreatitis risk of diagnostic ERCP. ## High-Yield: The **cholestatic pattern** (ALP and GGT elevation out of proportion to transaminases) combined with ductal dilatation on ultrasound defines obstructive jaundice. ERCP is both diagnostic and therapeutic in this setting. ## Management Algorithm for Obstructive Jaundice ```mermaid flowchart TD A[Obstructive jaundice + dilated ducts]:::outcome --> B{Diagnosis confirmed on imaging?}:::decision B -->|Yes, CBD stone| C[ERCP + sphincterotomy]:::action B -->|Uncertain| D[MRCP for confirmation]:::action D --> E{Stone confirmed?}:::decision E -->|Yes| C E -->|No| F[Investigate other causes]:::action C --> G[Stone extraction]:::action G --> H[Successful clearance]:::outcome ``` ## Why MRCP Before ERCP? - **Sensitivity/Specificity:** >90% for CBD stones; avoids unnecessary ERCP - **Safety:** Non-invasive; no risk of post-ERCP pancreatitis (~3–5% with diagnostic ERCP) - **Staging:** Identifies stone size, number, and location; guides ERCP technique - **Cost-effective:** Reduces unnecessary procedures ## ERCP Success Rates - **Stone extraction:** 85–95% success rate - **Complications:** Post-ERCP pancreatitis (~3–5%), bleeding, perforation (~0.5%) - **Contraindications:** Altered anatomy (post-gastrectomy), uncorrectable coagulopathy ## Clinical Pearl: **Spontaneous stone passage occurs in <15% of CBD stones; medical therapy (ursodeoxycholic acid) is ineffective for pigment/cholesterol stones.** Observation is not appropriate in symptomatic obstructive jaundice with confirmed stone. [cite:Harrison 21e Ch 297]