A 58-year-old man from Delhi presents with painless progressive jaundice for 3 weeks. He reports dark urine and pale stools. On examination, the liver is palpable 2 cm below the costal margin and non-tender. Abdominal examination reveals no ascites. Laboratory investigations show: total bilirubin 8.2 mg/dL (direct 6.8 mg/dL), ALP 320 IU/L, GGT 280 IU/L, ALT 45 IU/L. Abdominal ultrasound shows dilated intrahepatic bile ducts (IHBD) and a dilated common bile duct (CBD) measuring 12 mm with a hypoechoic lesion at the pancreatic head. What is the next most appropriate investigation to confirm the diagnosis and guide surgical management?

Explanation

## Clinical Presentation Analysis This patient presents with **painless progressive jaundice** with markedly elevated alkaline phosphatase and GGT (cholestatic pattern), a dilated CBD on ultrasound, and imaging evidence of a pancreatic head lesion. This constellation is classic for **pancreatic head malignancy causing extrahepatic biliary obstruction**. ## Why CECT Is the Next Step **Key Point:** CECT abdomen and pelvis is the imaging modality of choice for staging pancreatic cancer and assessing resectability before any intervention. CECT provides: - Tumor size, local extent, and involvement of adjacent structures (duodenum, portal vein, superior mesenteric vessels) - Assessment of distant metastases (liver, peritoneum, ascites) - Vascular involvement (critical for surgical planning) - Lymph node assessment - Baseline imaging for operative planning **High-Yield:** In obstructive jaundice from suspected pancreatic malignancy, **staging CT must precede any endoscopic or percutaneous intervention** to determine if the patient is a surgical candidate. ERCP/PTC are therapeutic interventions and should not be performed until resectability is confirmed. ## Role of Other Investigations | Investigation | Indication | Timing | | --- | --- | --- | | **CECT** | Staging, resectability assessment, vascular involvement | **First-line imaging** | | **MRCP** | Characterizing biliary tree anatomy when CT inconclusive; non-invasive | Secondary; lower sensitivity for pancreatic lesion characterization | | **ERCP** | Therapeutic drainage (stent placement) in unresectable/palliative cases | **After staging CT confirms unresectability** | | **PTC** | Intrahepatic cholestasis or IHBD involvement; when ERCP fails | Rarely first-line | **Clinical Pearl:** Performing ERCP before staging CT in suspected pancreatic cancer can contaminate the peritoneum with infected bile (cholangitis risk) and may preclude subsequent surgery. Always stage first. ## Algorithm for Obstructive Jaundice Workup ```mermaid flowchart TD A["Painless jaundice + dilated CBD on US"]:::outcome --> B{"Suspected etiology?"}:::decision B -->|"Pancreatic head lesion"| C["CECT abdomen/pelvis"]:::action C --> D{"Resectable?"}:::decision D -->|"Yes"| E["Proceed to surgery"]:::action D -->|"No"| F["ERCP + stent for palliation"]:::action B -->|"Choledocholithiasis"| G["MRCP or ERCP"]:::action B -->|"Cholangiocarcinoma"| C E --> H["Whipple or distal pancreatectomy"]:::action ``` **Mnemonic:** **STAGE before DRAIN** — Always Stage with CT before placing a Drain (ERCP/PTC) in suspected malignancy.