Acute Cholecystitis in an Elderly Patient With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Case Report.

A diagnosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is difficult to establish in elderly patients. Herein, we report a case of acute cholecystitis mimicking sepsis in an elderly patient with ANCA-associated vasculitis. A 99-year-old woman was transferred to a rural community hospital on account of anorexia and hypotension; there, she was initially diagnosed with sepsis and treated accordingly. However, she developed new-onset right upper quadrant tenderness on indirect fist percussion of the liver, and Murphy's sign was positive. While imaging did not reveal any findings suggestive of cholecystitis, the high index of suspicion for cholecystitis prompted an exploratory laparoscopy. Intraoperatively, the gallbladder wall was found to be inflamed, necessitating laparoscopic cholecystectomy. Histopathologic examination of the resected gallbladder showed neutrophilic infiltration and fibrinoid necrosis of the arterial walls. Perinuclear ANCA titers were elevated. These findings were consistent with a diagnosis of ANCA-associated vasculitis, and treatment with prednisolone markedly improved her condition. This case shows the difficulty encountered in differentiating between sepsis and ANCA-related vasculitis based on clinical features and relatively non-invasive diagnostic strategies alone. This study highlights the utility of invasive diagnostic procedures (e.g., biopsy) in elderly patients in whom a diagnosis of ANCA-associated vasculitis is difficult to establish.