Assessment of Gallbladder Aetiology: Key Features and Laboratory Investigations
The diagnosis of gallbladder pathology requires a combination of specific clinical findings, targeted laboratory tests (elevated WBC, CRP, and neutrophil count), and imaging studies, with no single finding sufficient to establish or exclude disease. 1
Clinical Features to Assess
Cardinal Symptoms and Signs
- Right upper quadrant pain or tenderness - the most consistent finding in gallbladder disease 1, 2
- Murphy's sign - inspiratory arrest during palpation of RUQ (positive likelihood ratio 2.8, though limited diagnostic power alone) 1, 3
- Fever - indicates inflammatory process 1, 2
- Nausea, vomiting, or food intolerance - common associated symptoms 1, 3
- Palpable gallbladder mass - suggests advanced or complicated disease 3
- Jaundice - when present, raises concern for common bile duct involvement or cholangitis 4
Important Clinical Context
- Duration and onset of symptoms - acute versus chronic presentation affects management 1
- Immunocompromised status - may present atypically with minimal physical findings despite severe inflammation 3
Laboratory Tests to Order
Essential Initial Labs
- Complete blood count (CBC) with differential - elevated white blood cell count is a key inflammatory marker 1, 2
- Neutrophil count specifically - strongest laboratory association with acute cholecystitis (70% sensitivity, 65.8% specificity) 1
- C-reactive protein (CRP) - elevated in gallbladder inflammation 1, 2
Labs for Common Bile Duct Stone Risk Stratification
- Liver function tests (LFTs) - assess for biliary obstruction 1
- Total and direct bilirubin - elevated levels suggest bile duct involvement 1
- Alkaline phosphatase and GGT - indicators of biliary stasis 4
Important Caveat
No single laboratory test has sufficient diagnostic power (likelihood ratios >1.6 or <0.4) to establish or exclude acute cholecystitis definitively - combination with clinical and imaging findings is mandatory. 1
Imaging Investigations
First-Line Imaging
- Abdominal ultrasound - initial imaging modality of choice with 98.6% sensitivity (one-sign criterion) 4, 5
- Look for: gallstones, gallbladder wall thickening, pericholecystic fluid, distended gallbladder, sonographic Murphy's sign 3, 4
Second-Line Imaging (if ultrasound equivocal)
- CT scan with IV contrast - 92-93.4% sensitivity for acute cholecystitis, particularly useful for complications (emphysematous cholecystitis, perforation, hemorrhage) 4, 5
Third-Line/Problem-Solving Imaging
- HIDA scan (hepatobiliary scintigraphy) - most sensitive overall imaging modality for cholecystitis 4
- MRI/MRCP - reserved for cholestatic presentations, evaluating bile duct stones, or when diagnosis remains uncertain 4, 6
Risk Stratification for Common Bile Duct Stones
Patients must be stratified for common bile duct stone risk using clinical, laboratory, and imaging findings combined. 2
- High-risk patients require preoperative ERCP 2
- Moderate-risk patients need second-level examinations (MRCP, EUS, or intraoperative cholangiography) 2
Common Pitfalls to Avoid
- Murphy's sign may be absent in patients who received pain medication prior to examination 3
- Relying on physical examination alone without laboratory or imaging confirmation leads to missed diagnoses 3
- Single test interpretation - the combination of history, examination, labs, and imaging yields positive likelihood ratio of 25.7 versus individual findings 1
- Overlooking immunocompromised patients who may have severe disease with minimal clinical findings 3