Acalculous Cholecystitis Presenting as a Septic Joint: A Case Report.

It is rare for acalculous cholecystitis to present with symptoms outside the abdomen; hence, making its diagnosis can be a challenge. We report a case of a 77-year-old male, with a relevant past medical history of left knee arthroplasty two years prior, who presented with left knee pain and swelling. Cultures from the arthrocentesis grew Clostridium perfringens, which led to a search for the source of infection. The right upper quadrant (RUQ) ultrasound (US) showed an enlarged gallbladder filled with sludge, but no cholelithiasis or secondary ultrasound findings were present to suggest acute cholecystitis. A computed tomography (CT) scan showed a distended gallbladder with diffuse gallbladder wall thickening and no stone but with suspicion for acalculous cholecystitis. A subsequent hepatobiliary (HIDA) scan confirmed the diagnosis of acalculous cholecystitis. Subsequently, the patient had a biliary drain placed. Bile cultures grew gram-positive rods consistent with Clostridium perfringens, confirming the source. With regards to the septic prosthetic joint, the patient underwent irrigation and debridement with polyethylene exchange without replacement of the prosthesis. The patient was also treated with six weeks of intravenous (IV) ertapenem (1 gram daily) and 12 months of moxifloxacin (400 mg daily). He had a cholecystectomy later and his symptoms were completely resolved.