What are the diagnostic criteria for acute cholecystitis according to the Tokyo Guidelines?

Diagnostic Criteria for Acute Cholecystitis

The diagnosis of acute cholecystitis requires a combination of local signs (Murphy's sign, right upper quadrant pain/tenderness, or palpable mass), systemic signs of inflammation (fever, elevated WBC, or elevated CRP), and confirmatory imaging findings—no single clinical or laboratory feature is sufficient to establish or exclude the diagnosis. 1

Tokyo Guidelines Diagnostic Framework

The Tokyo Guidelines establish a three-component diagnostic approach that requires:

1. Local Signs of Inflammation (at least one required)

• Murphy's sign (inspiratory arrest during palpation of the right upper quadrant) 2, 3, 4
• Right upper quadrant pain or tenderness 1, 2, 3
• Palpable mass, pain, or tenderness in the right upper quadrant 4, 5

2. Systemic Signs of Inflammation (at least one required)

• Fever (temperature elevation indicating systemic inflammatory response) 1, 2, 3
• Elevated white blood cell count (sensitivity 70%, specificity 65.8%, with neutrophil count showing strongest association) 1, 6
• Elevated C-reactive protein 1, 6, 2

3. Imaging Confirmation

• Ultrasound findings showing gallbladder inflammation (pericholecystic fluid, gallbladder wall thickening, distended gallbladder, gallstones) 2, 3
• Patients with suspected clinical findings confirmed by diagnostic imaging meet criteria for definite diagnosis 4, 5

Diagnostic Performance

The Tokyo Guidelines criteria demonstrate 91.2% sensitivity and 96.9% specificity when properly applied, though one validation study showed lower overall accuracy of 60.3% when all three components were strictly required 1, 5. The improved performance in the revised Tokyo Guidelines (TG13) came from clarifying the definition of "definite diagnosis" 5.

Essential Laboratory Workup

Beyond the basic inflammatory markers, obtain:

• Complete blood count with differential 6, 2
• Comprehensive metabolic panel including calcium (particularly critical in patients with prior parathyroidectomy, as hypocalcemia can mimic acute cholecystitis) 6
• Liver function tests (AST, ALT, alkaline phosphatase, bilirubin) to assess for common bile duct involvement 6
• Lipase or amylase to exclude pancreatitis 6

Imaging Algorithm

First-Line: Ultrasound

• Abdominal ultrasound is the initial imaging test of choice with sensitivity of 80.9-98.6% depending on criteria used (one-sign vs. two-sign criterion) 2
• Ultrasound has high sensitivity and specificity (81% and 83% respectively) and should be performed first 6, 2

Second-Line: CT with IV Contrast

• If ultrasound is equivocal but clinical suspicion remains high, proceed to CT scan with IV contrast 6, 2
• CT demonstrates 92-93.4% sensitivity for acute cholecystitis 6, 2

Third-Line: HIDA Scan or MRI/MRCP

• HIDA scan (hepatobiliary scintigraphy) is the most sensitive imaging modality overall for cholecystitis but is reserved for cases where ultrasound and CT are inconclusive 2
• MRI/MRCP can be used as an alternative third-line test 2

Critical Clinical Pitfalls

Do not rely on Murphy's sign alone—it has a positive likelihood ratio of only 2.8 (95% CI: 0.8-8.6), and the confidence interval crosses 1.0, indicating limited independent diagnostic value 1, 3. Murphy's sign may be absent in patients who received pain medication prior to examination 3.

Physical examination findings have limited standalone accuracy—right upper quadrant tenderness has a negative likelihood ratio of 0.4 (95% CI: 0.2-1.1), but again the confidence interval includes 1.0 1. No individual clinical sign or laboratory test achieves likelihood ratios higher than 1.6 or negative likelihood ratios lower than 0.4 1.

In patients with prior parathyroidectomy presenting with abdominal pain, always check serum calcium immediately, as severe hypocalcemia can cause abdominal cramping and tetany that mimics cholecystitis 6.

Immunocompromised patients may present atypically with minimal physical findings despite severe underlying inflammation 3.

Strength of Evidence

The combination approach using detailed history, complete clinical examination, laboratory tests, and imaging achieves a positive likelihood ratio of 25.7 and negative likelihood ratio of 0.24 when properly integrated 1. However, the optimal specific combination of these elements remains uncertain, with quality of evidence rated as very low for determining the best diagnostic algorithm 1.