A 28-year-old man with a bicuspid aortic valve presented with facial droop and slurred speech with several months of constitutional symptoms of night sweats, weight loss and productive cough. Examination confirmed aortic regurgitation, palpable spleen and left facial droop. Multiple peripheral blood cultures were negative. Inflammatory markers, cytoplasmic staining antineutrophil cytoplasmic antibodies (cANCA) and anti-PR3 antibody were all elevated. MRI of the brain and CT of the chest and abdomen confirmed embolic infarcts to brain, kidney and spleen. Transoesophageal echocardiogram (ECG) showed valve vegetations and severe aortic regurgitation. Endocardial Wegener's granulomatosis was considered. Aortic valve replacement was performed. Grindings from aortic valve leaflets were analysed for rpoB gene, which confirmed the presence of Bartonella henselae. Serological assays demonstrated B henselae IgM 20 (normal <20) and IgG >2048 (normal < 64). The patient completely recovered after prolonged antibiotic treatment. Culture-negative infective endocarditis may mimic vasculitis and be associated with positive cANCA. Serology and molecular techniques may aid diagnosis.