THE ABSENCE OF GALLSTONES ON POINT-OF-CARE ULTRASOUND RULES OUT ACUTE CHOLECYSTITIS

Julian Villar, MD, MPH, Shane M. Summers, MD, RDMS, Michael D. Menchine, MD, MPH, J. Christian Fox, MD, RDMS, and Ralph Wang, MD, RDMS

Goal:

To evaluate a simplified screening (presence or absence of gallstones) to rule out acute cholecystitis (AC) with superior sensitivity and negative predictive value than traditional screenings (inflammation, biliary obstruction, increased wall thickness, pericholecystic fluid, sonographic Murphy’s sign)

Methods:

• Secondary analysis of a prospective, cross-sectional, single-center study of patients presenting with suspected cholecystitis (RUQ or epigastric pain, fever, or vomiting).

• Presence of gallstones alone on POCUS was considered a positive test; absence of gallstones was considered negative.

• Patients were classified as positive for Acute Cholecystitis if they had a cholecystectomy (& positive pathology report) within 2 weeks of initial visit, and negative if they never underwent cholecystectomy, underwent cholecystectomy greater than 2 weeks from initial visit, or had negative pathology)

Results:

• All (23) cases of AC were correctly identified by presence of gallstones

• 15 patients had secondary signs of cholecystitis, but no gallstones. None had AC on surgical pathology

• 77 Patients had POCUS negative for gallstones; none were diagnosed with AC

• Using gallstones alone to diagnose AC had:

o sensitivity of 100% (i.e. nobody who had AC was negative for gallstones)

o specificity of 54.6% (i.e. people with stones may have had diagnoses other than AC)

o Negative Predictive Value of 100% (i.e. nobody without stones had AC)

o Positive Predictive value of 26.4% (i.e. not all who had stones had AC)

Limitations:

- Single center study

- Ultrasound is operator-dependent by nature

- Secondary analysis of previously collected data (however, no data was missing)

- Cannot be generalized to acalculous cholecystitis (however, this is very rare in the ambulatory population)

Conclusion:

The absence of gallstones can reliably rule out acute cholecystitis. However, in the presence of gallstones, secondary signs should still be utilized to rule in acute calculous cholecystitis

Post by Lynnia Tuckfield, MS4