Cholecystitis: Laboratory Evaluation and Treatment
Laboratory Workup
For suspected cholecystitis, obtain a complete blood count and comprehensive liver function panel including ALT, AST, bilirubin, alkaline phosphatase (ALP), and GGT. 1, 2
Key Laboratory Findings
- White blood cell count: Elevated in 70% of cases with cholecystitis (sensitivity 70%, specificity 65.8%) 2
- C-reactive protein: Elevated, indicating inflammatory response 2
- Bilirubin: Elevated (>1.3 mg/dL) suggests possible common bile duct involvement with 84% sensitivity and 91% specificity for CBD stones 3
- Alkaline phosphatase: Elevation >125 IU/L has 92% sensitivity and 79% specificity for CBD stones 3
- Transaminases (ALT/AST): May be elevated, particularly if biliary obstruction present 1, 3
Clinical Presentation to Assess
- Right upper quadrant pain and tenderness (negative likelihood ratio 0.4 when absent) 2
- Murphy's sign (positive likelihood ratio 2.8) 2
- Fever 1, 2
- Nausea/vomiting 4
Imaging Algorithm
Begin with abdominal ultrasound as the first-line imaging modality for all non-pregnant adults with suspected acute cholecystitis (sensitivity 81%, specificity 83%). 1, 2
Ultrasound Findings Diagnostic of Cholecystitis
- Pericholecystic fluid 1
- Distended gallbladder with edematous wall 1
- Gallstones, particularly if impacted in cystic duct 1
- Sonographic Murphy's sign 1
If Ultrasound is Equivocal
Obtain CT scan with IV contrast (sensitivity 92-93.4%). 1, 2 CT is particularly useful for identifying complications and ruling out alternative diagnoses. 1
If Both Ultrasound and CT are Equivocal
Obtain either HIDA scan or MRI/MRCP for definitive diagnosis. 1
- HIDA scan: Gold standard for acute cholecystitis diagnosis (sensitivity ~90%, specificity ~80%) 5, 6, 7
- MRI/MRCP: Provides better visualization of surrounding structures with 93% sensitivity and 96% specificity for CBD stones 3
Special Populations
- Pregnant patients: Use ultrasound or MRI as initial imaging (avoid CT due to radiation) 1
- Children: Mirror the adult imaging pathway (US → CT → HIDA/MRI) 1
Treatment Strategy
Uncomplicated Cholecystitis
Perform early laparoscopic cholecystectomy within 7-10 days of symptom onset, ideally within 1-3 days. 1, 4
- Single-dose antibiotic prophylaxis if surgery performed early 1
- No postoperative antibiotics needed if source control adequate 1
- Early surgery (within 3 days) reduces composite complications (11.8% vs 34.4% for delayed), shortens hospital stay (5.4 vs 10.0 days), and lowers costs 4
Complicated Cholecystitis
Perform laparoscopic cholecystectomy (or open if necessary) plus antibiotic therapy. 1
Antibiotic Duration Based on Patient Status
For immunocompetent, non-critically ill patients with adequate source control:
- Amoxicillin/clavulanate 2g/0.2g IV every 8 hours for 4 days 1
- Alternative for beta-lactam allergy: Eravacycline 1 mg/kg every 12 hours or Tigecycline 100 mg loading dose then 50 mg every 12 hours 1
For critically ill or immunocompromised patients with adequate source control:
- Piperacillin/tazobactam 6g/0.75g loading dose then 4g/0.5g every 6 hours (or 16g/2g continuous infusion) 1
- Continue antibiotics up to 7 days based on clinical response and inflammatory markers 1
For inadequate/delayed source control or high risk of ESBL organisms:
- Ertapenem 1g every 24 hours 1
Percutaneous Cholecystostomy
Reserve for patients with multiple comorbidities unfit for surgery who fail to improve after initial antibiotic therapy. 1 However, recognize that cholecystostomy has higher complication rates (65%) compared to laparoscopic cholecystectomy (12%) and is inferior for critically ill patients. 4
- Continue antibiotics for 4 days post-procedure 1
Pregnancy Considerations
Perform early laparoscopic cholecystectomy during any trimester as it reduces maternal-fetal complications (1.6% vs 18.4% for delayed management). 4
Elderly Patients (>65 years)
Laparoscopic cholecystectomy is preferred as it reduces 2-year mortality (15.2%) compared to nonoperative management (29.3%). 4
Critical Pitfall: Distinguishing Cholangitis from Cholecystitis
If patient presents with jaundice, fever/chills, RUQ pain, elevated bilirubin (>4 mg/dL), and imaging shows biliary dilatation or obstructing pathology, suspect acute cholangitis rather than isolated cholecystitis. 1, 3, 2 This requires different management including ERCP consideration and modified antibiotic coverage.
Monitoring for Stone Passage
Document resolution of biliary pain, jaundice, and fever clinically. 3 Confirm with normalization of bilirubin (<1.3 mg/dL) and ALP (<125 IU/L), plus ultrasound showing no CBD stone and duct diameter <10 mm. 3
Patients with ongoing signs of infection beyond 7 days of antibiotic treatment warrant diagnostic re-evaluation. 1