A 52-year-old woman presents to the emergency department with acute right upper quadrant pain, fever (38.5°C), and jaundice. She has a 10-year history of asymptomatic gallstones. On examination, she is icteric, with tenderness over the right costal margin and a palpable mass in the RUQ. Serum bilirubin is 4.2 mg/dL (direct 3.8), ALT 320 U/L, ALP 180 U/L, and amylase 85 U/L. Ultrasound shows a dilated common bile duct (8 mm), multiple gallstones, and a stone impacted in the cystic duct with pericholecystic fluid. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Acute Cholecystitis with Choledocholithiasis ### Key Clinical Features **Key Point:** The triad of fever, RUQ pain, and jaundice in the setting of gallstone disease with imaging evidence of cystic duct obstruction and dilated CBD indicates acute cholecystitis complicated by choledocholithiasis. ### Diagnostic Criteria Met | Feature | Finding | Significance | |---------|---------|---------------| | **Cystic duct obstruction** | Stone impacted in cystic duct | Diagnostic of acute cholecystitis | | **Systemic inflammation** | Fever 38.5°C, icteric appearance | Suggests bacterial superinfection | | **Cholestasis pattern** | Direct hyperbilirubinemia, ↑ ALP | Biliary obstruction | | **Dilated CBD** | 8 mm on ultrasound | Secondary to stone obstruction | | **Pericholecystic fluid** | Present on imaging | Inflammatory response | ### Pathophysiology 1. **Cystic duct obstruction** → bile stasis and gallbladder inflammation 2. **Increased intraluminal pressure** → mucosal ischemia and bacterial translocation 3. **Secondary stone migration** → common bile duct obstruction 4. **Biliary obstruction** → conjugated hyperbilirubinemia and cholangitis risk **High-Yield:** The presence of both fever + jaundice + RUQ pain + imaging evidence of cystic duct stone + dilated CBD = acute cholecystitis WITH choledocholithiasis, not isolated cholangitis. ### Management Implications ```mermaid flowchart TD A[Acute cholecystitis + dilated CBD]:::outcome --> B{Cholangitis signs?}:::decision B -->|Yes: fever + jaundice + RUQ pain| C[ERCP + sphincterotomy]:::action B -->|No: uncomplicated| D[Cholecystectomy ± IOC]:::action C --> E[Biliary drainage]:::outcome E --> F[Elective cholecystectomy in 4-6 weeks]:::action D --> G[Single-stage resolution]:::outcome ``` **Clinical Pearl:** When acute cholecystitis is accompanied by jaundice and dilated CBD, assume choledocholithiasis until proven otherwise. Early ERCP (within 24–48 hours) is indicated if there is evidence of ascending cholangitis (fever, elevated WBC, positive blood cultures). **Key Point:** Amylase is normal (85 U/L), ruling out acute pancreatitis as the primary diagnosis—gallstone pancreatitis would show markedly elevated amylase and lipase. ### Why Not the Other Diagnoses? - **Acute pancreatitis:** Amylase is normal; pain pattern and imaging are consistent with cholecystitis, not pancreatic inflammation. - **Biliary colic with cholangitis:** Biliary colic is intermittent and self-limited; this patient has sustained fever and systemic signs of infection (acute cholecystitis). - **Acute cholangitis without cholecystitis:** Cystic duct stone with pericholecystic fluid definitively indicates cholecystitis; cholangitis is a secondary complication here.