What are the criteria for diagnosing calculous cholecystitis?

Diagnostic Criteria for Calculous Cholecystitis

The diagnosis of acute calculous cholecystitis requires a combination of clinical findings (right upper quadrant pain/tenderness, Murphy's sign, fever), laboratory abnormalities (elevated WBC and CRP), and imaging confirmation showing gallbladder inflammation—no single finding is sufficient to establish or exclude the diagnosis. 1

Algorithmic Diagnostic Approach

Step 1: Clinical Assessment

You must identify the following clinical features, as no single finding has adequate diagnostic power alone 1:

• Right upper quadrant pain or tenderness - present in 97.9% of cases, making it the most sensitive clinical finding 2
• Murphy's sign - has a positive likelihood ratio of only 2.8 (95% CI 0.8-8.6), meaning it's helpful when positive but not definitive 1, 3
• Fever - a systemic inflammatory sign commonly present 4
• Vomiting or food intolerance - supportive but nonspecific findings 1
• Palpable gallbladder mass - rare (sensitivity 0.8%) but indicates complicated disease when present 2

Critical pitfall: Murphy's sign may be absent in patients who received pain medication before examination, and physical examination alone has limited accuracy 4

Step 2: Laboratory Testing

Order the following tests as part of the diagnostic combination 1:

• Elevated C-reactive protein - useful inflammatory marker; the combination of RUQ pain plus elevated CRP has 55.1% sensitivity for definitive diagnosis 2
• Elevated white blood cell count - sensitivity of 70%, specificity 65.8%; the combination of RUQ pain plus elevated WBC has 53.7% sensitivity 5, 2

Important caveat: Laboratory findings are not specific and must be interpreted with clinical and imaging findings 1

Step 3: Imaging Confirmation

Proceed with imaging in the following sequence 6:

First-line: Abdominal ultrasound 6

• Sensitivity of 81-98.6% and specificity of 83% 5, 6
• Look for: thickened gallbladder wall (92.3% sensitivity), pericholecystic fluid, gallbladder distension, and gallstones 4, 2
• Thickened gallbladder wall is the most sensitive imaging finding 2

Second-line: CT with IV contrast (if ultrasound equivocal) 6

• Sensitivity of 92-93.4% 6
• Can detect complications including perforation, gas formation, and hemorrhage 5

Third-line: HIDA scan (Tc-99m hepatobiliary scintigraphy) 6

• Most sensitive imaging modality overall for cholecystitis 5
• Use when clinical suspicion remains high despite negative or equivocal ultrasound 5

Tokyo Guidelines Framework

The Tokyo Guidelines provide a structured diagnostic framework requiring 6, 2:

• One local sign: Murphy's sign OR mass/pain/tenderness in RUQ
• One systemic sign: fever OR elevated WBC OR elevated CRP
• Imaging confirmation: evidence of gallbladder inflammation

Limitation to note: The Tokyo Guidelines have an overall accuracy of only 60.3%, emphasizing why you cannot rely on this framework alone 6

Diagnostic Performance of Combined Findings

The clinical gestalt combining history, physical examination, and laboratory tests achieves a positive likelihood ratio of 25-30, which is substantially better than any individual finding 3. The study by Eskelinen demonstrated that proper combination of findings yields a positive LR of 25.7 and negative LR of 0.24 1.

Special Clinical Scenarios

Patients without typical imaging findings (7.2% of cases) 2:

• More likely to be afebrile
• May have normal CRP values
• Require higher clinical suspicion and possibly advanced imaging

Immunocompromised patients 4:

• May present with minimal physical findings despite severe inflammation
• Require lower threshold for imaging and intervention