Clonorchis sinensis infection are associated with calcium phosphate gallbladder stones: A single-center retrospective observational study in China

Limited studies have been conducted on calcium phosphate gallbladder stones, to enhance our comprehension of the formation, we investigated the clinical characteristics and the potential link between calcium phosphate gallbladder stones and Clonorchis sinensis (C sinensis) infection. A retrospective observational study was conducted involving 4451 patients who underwent gallbladder-preserving cholelithotomy between January 2013 and January 2022. Based on the regional prevalence of C sinensis infection, the patients were categorized into 2 groups: those from high-incidence regions and those from low-incidence regions. We analyzed their appearance, texture, and clinical attributes. Furthermore, we utilized light microscopy to detect C sinensis eggs and χ2 tests to analyze the detection rate. Additionally, Fourier transform infrared spectroscopy was employed to analyze stone composition, and scanning electron microscopy combined with element distribution analysis (SEM-EDAX) was used to observe microstructure and element distribution. A total of 245 cases were identified as calcium phosphate stones, which constituted 5.50% (245/4451) of all gallbladder stone cases. These stones exhibited various degrees of bilirubinate mixing, with nearly 19.18% (47/245) being combined with calcium carbonate (CaCO3). The presence of C sinensis eggs in calcium phosphate stones was significantly higher compared to non-calcium phosphate-CaCO3-bilirubinate stones (P < .05). Moreover, the prevalence of calcium phosphate stones was notably greater in C sinensis high-incidence regions than in low-incidence regions (P < .05). Calcium phosphate stones represent a significant subset of gallbladder stones. They frequently occur in combination with bilirubinate in varying proportions, and less commonly with other components. The development of calcium phosphate stones was associated with C sinensis infection. Therefore, effective prevention of this parasitic infection is essential for reducing the risk of calcium phosphate stone formation.