A 58-year-old man presents with painless progressive jaundice, pale stools, and dark urine for 3 weeks. Abdominal examination reveals a palpable gallbladder. Ultrasound shows dilated intrahepatic and extrahepatic bile ducts with a dilated gallbladder. What is the most common cause of obstructive jaundice in this clinical presentation?

Explanation

## Most Common Cause of Obstructive Jaundice **Key Point:** Pancreatic head carcinoma is the most common cause of obstructive jaundice due to malignancy in India and worldwide, accounting for 60–70% of malignant causes of biliary obstruction. ### Clinical Features Favouring Pancreatic Carcinoma | Feature | Pancreatic Carcinoma | Choledocholithiasis | Cholangiocarcinoma | |---------|----------------------|---------------------|--------------------| | **Onset** | Painless, progressive | Often colicky pain | Painless, insidious | | **Palpable GB** | Yes (Courvoisier sign) | No (contracted GB) | Variable | | **Age** | 50–70 years | Any age | 50–70 years | | **Frequency** | Most common (malignant) | Most common (overall) | Rare (1–2%) | | **Prognosis** | Poor | Excellent if treated | Poor | **High-Yield:** Courvoisier sign (palpable, non-tender gallbladder in obstructive jaundice) is classic for pancreatic head carcinoma because the duct obstruction is gradual and distal to the cystic duct, allowing the GB to distend. In choledocholithiasis, the GB is typically contracted due to chronic inflammation. ### Why Pancreatic Carcinoma Is Most Common (Malignant Cause) 1. **Anatomical proximity**: Pancreatic head surrounds the common bile duct; tumour growth directly compresses the CBD. 2. **Presentation**: Painless jaundice is the hallmark — pain suggests advanced disease or pancreatitis. 3. **Epidemiology**: Incidence ~10 per 100,000; accounts for ~3% of all cancers but 90% of pancreatic malignancies are adenocarcinoma of the head. **Clinical Pearl:** The combination of **painless jaundice + palpable gallbladder + dilated intrahepatic ducts** is pathognomonic for distal bile duct obstruction, most commonly pancreatic head carcinoma. ### Overall Hierarchy of Obstructive Jaundice Causes ```mermaid flowchart TD A[Obstructive Jaundice]:::outcome --> B{Aetiology?}:::decision B -->|Benign| C[Choledocholithiasis]:::action B -->|Malignant| D[Pancreatic head CA]:::action C --> E[Most common overall<br/>60-80% of cases]:::outcome D --> F[Most common malignant<br/>60-70% of malignant cases]:::outcome B -->|Other benign| G[Stricture, Pancreatitis]:::action B -->|Other malignant| H[Cholangiocarcinoma,<br/>Ampullary CA]:::action ``` **Mnemonic:** **CHAMP** — Common causes of Obstructive Jaundice: - **C**holedocholithiasis (most common overall) - **H**eadache of pancreatic carcinoma (most common malignancy) - **A**mpullary carcinoma - **M**alignancy (cholangiocarcinoma) - **P**ancreatitis (stricture) [cite:Bailey & Love 28e Ch 70]