A patient with RUQ pain, jaundice, hyperbilirubinemia, leukocytosis, and a dilated common bile duct with multiple gallstones, what is the most likely diagnosis?

Diagnosis: Ascending Cholangitis

The most likely diagnosis is D. Ascending cholangitis, given the combination of RUQ pain, jaundice (yellow sclera), fever/systemic illness (unwell appearance), leukocytosis, and dilated common bile duct with gallstones—this represents Charcot's triad (fever, jaundice, RUQ pain) with laboratory confirmation of biliary obstruction and infection. 1

Clinical Reasoning

Why Ascending Cholangitis is Most Likely

The patient presents with the classic features that distinguish cholangitis from other biliary pathology:

• Charcot's Triad is present: RUQ pain + jaundice (elevated bilirubin 30 μmol/L) + systemic signs of infection (unwell appearance, leukocytosis 15 × 10^9/L) 2, 1
• Laboratory findings confirm biliary obstruction with infection: Markedly elevated alkaline phosphatase (280 IU/L), hyperbilirubinemia, and leukocytosis indicate both obstruction and active infection 2
• Imaging demonstrates the anatomic substrate: Dilated common bile duct (1 cm) with multiple gallstones confirms choledocholithiasis as the obstructing cause 2, 3

Why Other Diagnoses Are Less Likely

Acute Cholecystitis (Option B) is excluded because:

• No pericholecystic fluid on ultrasound, which has 67-84% sensitivity for acute cholecystitis 2
• The degree of hyperbilirubinemia (30 μmol/L) and CBD dilation (1 cm) far exceed what would be expected from uncomplicated cholecystitis 2
• Cholecystitis typically presents with localized gallbladder inflammation without significant CBD dilation 2

Choledocholithiasis alone (Option C) is insufficient because:

• While CBD stones are present, the clinical picture includes systemic infection (leukocytosis, unwell appearance) 4
• Uncomplicated choledocholithiasis causes obstructive jaundice but not the fever and systemic inflammatory response seen here 3
• The presence of infection transforms simple choledocholithiasis into cholangitis 4

Acute Pancreatitis (Option A) is unlikely because:

• No mention of elevated amylase or lipase 1
• The clinical presentation emphasizes biliary obstruction and infection rather than pancreatic inflammation 1
• While gallstone pancreatitis can occur with choledocholithiasis, the dominant clinical picture here is cholangitis 1

Critical Management Implications

This diagnosis requires urgent intervention within 24 hours:

• Immediate resuscitation: IV fluids, broad-spectrum antibiotics, and hemodynamic stabilization 1
• Urgent ERCP with sphincterotomy and stone extraction: This is the definitive treatment for cholangitis secondary to choledocholithiasis, with 90% success rate 2, 5
• Biliary decompression is lifesaving: Untreated cholangitis can progress to septic shock and death 2

Common Pitfalls to Avoid

• Do not delay intervention for additional imaging: The combination of clinical findings, laboratory values, and ultrasound showing CBD dilation with stones is sufficient for diagnosis 1
• Do not confuse simple choledocholithiasis with cholangitis: The presence of systemic infection (leukocytosis, unwell appearance) distinguishes cholangitis and mandates urgent rather than elective management 4
• Do not rely solely on elevated liver function tests: While alkaline phosphatase and bilirubin are elevated, the diagnosis rests on the complete clinical picture including signs of infection 2