Gas-Containing Biliary Calculi: Case Series and a Systematic Review

Background: Cholelithiasis is a common gallbladder finding leading to cholecystitis in 7% of cases. Sonographic imaging or computed tomography scans are commonly employed for the diagnosis of benign gallbladder disease. Air within the gallbladder might carry various diagnoses. As opposed to pathologic air in the gallbladder seen in emphysematous cholecystitis, gas-containing gallstones are no more pathological than the exclusive presence of gallstones. In the present report, we review the incidence, physiology, typical characteristics, and clinical significance of gas-containing gallstones within the gallbladder. Methods: We performed an institutional review of all patients with benign gallbladder disease over the past 16 years (2005 to 2021) to identify patients with gas-containing gallstones in the gallbladder. We performed a review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) to identify all reported cases of patients with gas-containing biliary calculi within the gallbladder. Results: Our institutional review identified 5 patients with gas-containing biliary calculi in 1252 consecutive cholecystectomies; 4 of which had cholecystitis, while 1 was an incidental finding. Our review of the literature identified 30 manuscripts documenting 54 unique patients with gas-containing biliary calculi. None of these patients had consequential pathology related to gas in the stones other than that caused by the gallstones (ie, biliary colic and cholecystitis). Conclusions: Gas-containing biliary calculi are uncommon. How gas finds itself within gallstones within the gallbladder is not entirely clear. Gas-containing gallstones should not be interpreted as free gas within the gallbladder or within an abscess.