What is cholecystitis?

Cholecystitis Definition and Management

Cholecystitis is defined as inflammation of the gallbladder, most commonly caused by gallstone obstruction of the cystic duct (90-95% of cases), with the remaining 5-10% being acalculous cholecystitis occurring in critically ill patients. 1, 2

Pathophysiology and Progression

Acute cholecystitis follows a predictable progression if left untreated:

• Early phase (2-4 days): Edematous cholecystitis with congestion and edema
• Middle phase (3-5 days): Necrotizing cholecystitis with bleeding and necrosis
• Late phase (7-10 days): Suppurative (purulent) cholecystitis
• Beyond 10 days: Progression to subacute and eventually chronic cholecystitis 3

Diagnostic Criteria

Clinical Presentation

• Right upper quadrant pain
• Fever
• Nausea (often associated with eating)
• Physical examination finding of right upper quadrant tenderness 2

Imaging Findings

First-line imaging: Ultrasonography

• Sensitivity: ~81%, Specificity: ~83%
• Key diagnostic findings:
  • Gallstones
  • Gallbladder wall thickening (≥5mm)
  • Pericholecystic fluid
  • Distended gallbladder
  • Positive sonographic Murphy's sign (tenderness when probe pressed against gallbladder) 1, 4

Second-line imaging (when ultrasound is inconclusive):

• Hepatobiliary scintigraphy (HIDA scan)

  • Gold standard diagnostic test
  • Absence of gallbladder filling within 60 minutes after tracer administration indicates cystic duct obstruction
  • Sensitivity: 80-90% for acute cholecystitis 4, 2

• MRI with MRCP

  • Excellent for detecting cholelithiasis/choledocholithiasis (sensitivity 85-100%)
  • Can distinguish acute from chronic cholecystitis:
    • Acute: T2 signal hyperintensity (edema)
    • Chronic: Low signal intensity wall thickening 4

• CT with IV contrast

  • Useful for detecting complications
  • Less sensitive for gallstones (~75% sensitivity)
  • Helpful for identifying fluid collections, bilomas, ductal dilation 4, 1

Complications

Serious complications can develop if cholecystitis is left untreated:

• Gangrenous cholecystitis
• Emphysematous cholecystitis
• Gallbladder perforation (bile peritonitis)
• Hemorrhagic cholecystitis
• Peri-gallbladder abscess
• Internal biliary fistula 1, 5, 3

Management

Surgical management:

• Urgent laparoscopic cholecystectomy within 1-3 days of diagnosis is associated with:
  • Fewer postoperative complications (11.8% vs 34.4% for delayed surgery)
  • Shorter hospital stays (5.4 vs 10.0 days)
  • Lower hospital costs 1, 2

Antibiotic therapy:

• First-line options include:
  • Amoxicillin/Clavulanate 2g/0.2g q8h
  • Ceftriaxone + Metronidazole
  • Ciprofloxacin + Metronidazole
  • Piperacillin/Tazobactam (for healthcare-associated infections) 1

Special populations:

• Elderly patients: Require careful antibiotic management due to altered pharmacokinetics
• Pregnant patients: Early laparoscopic cholecystectomy is recommended during all trimesters
• High-risk patients: Percutaneous cholecystostomy tube placement may be considered for patients unfit for surgery 1, 2

Important Clinical Pearls

• Acalculous cholecystitis (5-10% of cases) typically occurs in critically ill patients and has a higher mortality rate (45.2%) compared to calculous cholecystitis (21.2%) 1
• Daily assessment of clinical response and monitoring of renal function are crucial, especially in elderly patients 1
• Patients with ongoing signs of infection beyond 7 days warrant further diagnostic investigation 1
• Bile duct injuries are among the most serious complications of laparoscopic cholecystectomy 1

Remember that early diagnosis and treatment are essential to prevent progression to complicated cholecystitis and its associated higher morbidity and mortality.