Introduction: Point-of-care ultrasound (POCUS) is a rapid bedside tool, particularly in undifferentiated emergency department patients. Point-of-care ultrasound can investigate potential intra-abdominal infections in febrile patients, especially in the elderly, who often present atypically without abdominal pain or localizing symptoms.

Case Report: We highlight the important POCUS findings of cholecystoduodenal fistula and staghorn calculus in a febrile, elderly patient with dementia.

Conclusion: Early recognition of cholecystoduodenal fistula and staghorn calculus using POCUS can expedite appropriate antibiotic and interventional treatment for improved patient outcomes.