Evolution of Secondary Findings in Acute Cholecystitis: A Temporal Analysis from Point-of-Care Ultrasound to Subsequent Imaging

Abstract

Background: Early sonographic signs of cholecystitis include cholelithiasis and gallbladder tenderness, while gallbladder wall changes (GWC), such as wall thickening and pericholecystic fluid, occur later. Surgeons often rely on GWC to guide admission decisions.

Study objectives: We sought to assess the prevalence and timing of the detection of GWC among patients without baseline GWC on initial point-of-care ultrasound (PoCUS). Secondary aims were to determine whether the presence or absence of GWC was associated with differences in hospital length of stay (LOS) or the proportion of acute cholecystitis.

Methods: This dual-site retrospective cohort study included admitted adult emergency department (ED) patients (11/1/20-5/1/24) who underwent biliary PoCUS and subsequent diagnostic imaging. Exclusions included known cholecystitis, hepatobiliary malignancy, liver or heart failure, renal failure, or prior cholecystectomy. Cholecystitis was defined by inpatient cholecystectomy, percutaneous cholecystostomy, or intravenous antibiotics with delayed cholecystectomy and chart diagnosis of cholecystitis. Time intervals between PoCUS and subsequent imaging, dynamic GWC prevalence, and associations with cholecystitis and LOS were analyzed.

Results: Of 440 patients screened, 352 were included; 174 (49.4%) had cholecystitis. Among 252 patients without initial GWC, 49 (19.4%) developed GWC over a median of 4 hours, while 203 remained unchanged. Stones and a positive sonographic Murphy's sign were associated with dynamic GWC (p = 0.019) and a cholecystitis diagnosis (p = 0.006). Patients with dynamic GWC had longer hospital LOS (p = 0.002).

Conclusion: Cholecystitis progresses dynamically, and GWC may not be present during ED assessments. Serial imaging, including PoCUS, could enable earlier identification of disease progression, informing timely clinical decision-making.

Keywords: Biliary ultrasound; Cholecystitis; Gallbladder wall thickening; Pericholecystic fluid; Point-of-care ultrasound.