Touch Not the Cat Bot a Glove*: ANCA-positive Pauci-immune Necrotizing Glomerulonephritis Secondary to Bartonella Henselae

A 36-year-old male presented with a secondary, but anti-neutrophil cytoplasmic antibody (ANCA) (proteinase-3) positive, vasculitis with renal insufficiency due to a pauci-immune necrotizing glomerulonephritis. An infective process was initially excluded by blood cultures and an echocardiogram prior to immunosuppression. The patient's condition failed to improve and re-evaluation confirmed infective endocarditis requiring valve replacement. Subsequent tissue cultures identified Bartonella henselae. Antibiotic treatment led to full resolution of physical, biochemical and immunological markers. This is the first case of B. henselae endocarditis-associated ANCA positivity with a pauci-immune glomerulonephritis. It demonstrates the importance of revisiting standard investigations in patients not improving expectantly on conventional therapy.