A patient with subacute bacterial endocarditis and positive PR3-ANCA: A case report and literature review

Patients with Subacute Bacterial Endocarditis (SBE) may present with multisystem disorders mimicking autoimmune diseases, such as An Antineutrophil Cytoplasmic Antibody (ANCA) - Associated Vasculitis (AAV). In this report, we present a 72-year-old female patient with streptococcal SBE who developed multiple inflammatory abnormalities, including ANCA positivity, which was complicated by the occurrence of leukocytoclastic vasculitis, glomerulonephritis, acute myocardial infarction, heart failure and subarachnoid hemorrhage. The patient had previously known mitral valve regurgitation. Repeated transthoracic echocardiography showed a floating lesion in the area of the mitral valve corresponding to chronic vegetation and confirmed the suspicion of SBE. Antibiotic treatment resulted in the decline of inflammatory parameters and complete recovery of renal function. Conservative treatment of acute myocardial infarction and neurorehabilitation were successful. Repeated ANCA tests were negative. Previously reported cases showed that ANCA-positive SBE can involve multiple organs. Distinguishing between AAV and SBE can sometimes be very difficult because of their clinical and serological similarities. Such a wide clinical presentation requires intensive monitoring of these patients. In conclusion, if systemic vasculitis is suspected, it is necessary to exclude diseases that mimic vasculitis, such as SBE.