Acute cholecystitis caused by granulomatosis with polyangiitis: A rare case

Granulomatosis with polyangiitis (GPA) most commonly affects the kidneys and lungs, while the involvement of other organs is rare. We present a case of vasculitic changes in the gallbladder as the initial manifestation of GPA. A 65-year-old woman was admitted with fever and generalized weakness. Physical examination revealed signs of dehydration, mild hypotension and tachycardia without abdominal tenderness or a positive Murphy's sign. Laboratory evaluation revealed normocytic anemia and elevated markers of inflammation. Urinalysis revealed proteinuria and hematuria, but cultures and imaging were unremarkable. Despite empirical intravenous antibiotic therapy, the symptoms persisted. A subsequent computed tomography (CT) scan revealed calculous cholecystitis, leading to laparoscopic cholecystectomy. Histopathology of the gallbladder demonstrated small-vessel vasculitis. Further work-up revealed positive proteinase 3-anti-neutrophil cytoplasmic antibodies (PR3-ANCA) and declining renal function, consistent with a diagnosis of GPA. The patient was treated with glucocorticoids and intravenous cyclophosphamide, resulting in clinical and laboratory improvement. This case highlights the importance of considering systemic vasculitis in patients with persistent fever and non-specific systemic symptoms, especially when conventional causes are excluded. Gallbladder vasculitis, though extremely rare, can be the initial presentation of GPA.