A 58-year-old man presents with painless jaundice, pale stools, and dark urine for 3 weeks. Ultrasound shows dilated intrahepatic and extrahepatic bile ducts with a dilated common bile duct measuring 12 mm. No gallstones are seen. What is the most common cause of obstructive jaundice in this clinical scenario?

Explanation

## Most Common Cause of Obstructive Jaundice **Key Point:** Pancreatic head carcinoma is the most common malignant cause of obstructive jaundice, accounting for 20–30% of all cases of obstructive jaundice in developed countries. In this patient, the absence of gallstones, painless jaundice, and progressive biliary obstruction are classic for pancreatic malignancy. ### Epidemiology of Obstructive Jaundice Causes | Cause | Frequency | Key Features | |-------|-----------|-------------| | **Choledocholithiasis** | 40–60% (most common overall) | Colicky pain, recurrent episodes, stones on imaging | | **Pancreatic head carcinoma** | 20–30% (most common malignancy) | Painless jaundice, weight loss, elderly, no stones | | **Cholangiocarcinoma** | 10–15% | Intrahepatic/extrahepatic duct stricture, progressive | | **Biliary stricture** | 5–10% | Post-surgical history, benign etiology | **High-Yield:** While choledocholithiasis is the *overall* most common cause of obstructive jaundice, the clinical presentation in this case—**painless jaundice** with **no gallstones**—strongly points to **pancreatic head carcinoma** as the most likely diagnosis. This distinction is critical in NEET PG exams. ### Clinical Pearl: Courvoisier's Sign A palpable, non-tender gallbladder in a jaundiced patient suggests **malignant obstruction** (pancreatic or cholangiocarcinoma) rather than stones, because: - In stone disease, the gallbladder is often fibrotic and contracted. - In malignancy, the gallbladder distends due to gradual obstruction downstream. ### Diagnostic Workup Algorithm ```mermaid flowchart TD A[Obstructive Jaundice]:::outcome --> B{Gallstones on US?}:::decision B -->|Yes| C[Choledocholithiasis]:::outcome B -->|No| D{Painless jaundice + weight loss?}:::decision D -->|Yes| E[Pancreatic head carcinoma]:::action D -->|No| F{Intrahepatic duct dilation?}:::decision F -->|Yes| G[Cholangiocarcinoma]:::outcome F -->|No| H[Biliary stricture]:::outcome ``` **Warning:** Do not confuse overall frequency with clinical context. Choledocholithiasis is most common in the general population, but in a patient with **painless jaundice and no stones**, pancreatic carcinoma must be ruled out urgently.