What are the diagnostic tests and treatment options for cholecystitis?

Diagnostic Tests for Cholecystitis

Start with abdominal ultrasound as your initial imaging test for suspected acute cholecystitis in non-pregnant adults, as it remains the most appropriate first-line modality despite CT having higher sensitivity in some settings. 1

Initial Diagnostic Approach

Clinical Assessment

The diagnosis requires a combination of clinical, laboratory, and imaging findings—no single test is sufficient: 1, 2

Clinical signs to identify:

• Murphy's sign (focal tenderness over the gallbladder during inspiration, stopping the patient's breath) 2, 3
• Right upper quadrant pain and tenderness 1, 3
• Fever 1, 3
• Vomiting or food intolerance 1

Laboratory findings:

• Elevated white blood cell count (particularly neutrophil count) 1, 4
• Elevated C-reactive protein 1

Important caveat: Murphy's sign has limited diagnostic power alone (positive LR 2.8), and may be absent in elderly, diabetic, or immunocompromised patients despite severe disease. 1, 2 Pain medications given before examination invalidate a negative Murphy's sign. 2

Initial Imaging: Ultrasound First

For non-pregnant adults: Obtain abdominal ultrasound as the initial imaging modality. 1 Recent evidence shows ultrasound has 98.6% sensitivity using a one-sign criterion and 80.9% sensitivity using a two-sign criterion in community settings. 4

Key ultrasound findings:

• Cholelithiasis (gallstones) - detected with 95.9% sensitivity 4
• Thickened gallbladder wall (>3mm) - detected with 92.3% sensitivity 4
• Pericholecystic fluid 4
• Gallbladder distension 4
• Sonographic Murphy's sign 2

For pregnant patients: Either ultrasound or MRI can be used initially, though guidelines cannot recommend one over the other. 1

Sequential Imaging When Initial Tests Are Equivocal

If Ultrasound Is Non-Diagnostic

Obtain CT scan with IV contrast as the next step if clinical suspicion persists after an equivocal ultrasound. 1 While CT shows 92-93.4% sensitivity for acute cholecystitis 4, 5, it is particularly useful when:

• Patients lack typical clinical signs 5
• Patients are older, male, or have multiple comorbidities 5
• Complicated cholecystitis is suspected 2

CT advantages over ultrasound:

• More sensitive for pericholecystic fluid (83.6% vs lower on US) 4
• More sensitive for gallbladder distension (95.7%) 4
• Better for detecting complications 2

CT limitations:

• Less sensitive for detecting gallstones (60% vs 87% for ultrasound) 5

If Both Ultrasound and CT Are Non-Diagnostic

For suspected acute cholecystitis: Obtain either HIDA scan (hepatobiliary scintigraphy) or MRI/MRCP as third-line imaging. 1 HIDA scan is the most sensitive imaging modality for cholecystitis overall. 6

For suspected acute cholangitis: MRI/MRCP is the reasonable option, as it can identify biliary dilatation, strictures, stones, or obstructing masses. 1

Special Diagnostic Considerations

Acute Cholangitis Diagnosis

Requires the triad of: 1

• Clinical signs: jaundice, fever, chills, right upper quadrant pain
• Laboratory findings: indicators of inflammation and biliary stasis
• Imaging findings: biliary dilatation or evidence of etiology (stricture, stone, mass)

Acalculous Cholecystitis

This occurs in critically ill patients (trauma, surgery, shock, burns, sepsis, TPN, prolonged fasting) and is particularly difficult to diagnose. 7 Sequential ultrasounds and HIDA scans are most reliable. 7 Maintain high clinical suspicion as early diagnosis is critical—mortality is high without timely intervention. 7

Tokyo Guidelines Criteria

The validated diagnostic criteria include: 8

• One local sign (Murphy's sign, mass/pain/tenderness in RUQ)
• One systemic sign (fever, elevated WBC, elevated CRP)
• Confirmation by imaging

Note that validation studies show only 60.3% overall accuracy for these criteria, with neutrophil count being the most statistically significant laboratory marker. 1

Common Diagnostic Pitfalls

• Don't rely on physical examination alone—Murphy's sign and RUQ tenderness have insufficient diagnostic power as isolated findings. 1, 2
• Don't skip ultrasound and go straight to CT in typical presentations—ultrasound remains first-line despite CT's higher sensitivity in some studies. 1, 4
• Don't miss acalculous cholecystitis in ICU patients—maintain high suspicion even with atypical presentations. 7
• Don't assume negative imaging rules out disease in immunocompromised patients who may have minimal findings despite severe inflammation. 3