Renal Disease in Patients with Infective Endocarditis and Antineutrophil Cytoplasmic Antibodies

Infective endocarditis triggers the development of multiple immunological reactions, including the formation of autoantibodies. Certain categories of autoantibodies triggered by endocarditis, for example, antineutrophil cytoplamic antibodies (ANCA), may cause secondary diseases that require special diagnostic approaches and at times special interventions. Formation of ANCA secondary to endocarditis has been linked to vasculitis and renal disease. To evaluate the characteristics of renal disease in patients with infective endocarditis developing ANCA, we reviewed the reports of this syndrome. Forty-eight patients with endocarditis and positive ANCA serology were identified. Renal manifestations, including hematuria, proteinuria, and various levels of decrease in glomerular filtration rate, were almost ubiquitous. Renal histology, available from percutaneous kidney biopsy or autopsy in 28 subjects, revealed various pictures, including tubular injury, acute interstitial nephritis, post-infectious glomerulonephritis, pauciimmune glomerulonephritis, and others. The histological characterization of the renal and other lesions, along with the clinical picture, influenced the methods of treatment. Treatment of the underlying infection with antibiotics was associated with substantial improvement of clinical and laboratory features in most patients. However, a small number of patients with ANCA-mediated renal disease required immunosuppressive medications (corticosteroids, cyclophosphamide) or plasma exchange, with prompt and sustained response to these treatments. Ten patients died as a consequence of the endocarditis and 20 patients had surgical cardiac interventions. Disease secondary to autoantibodies triggered by endocarditis may require immunosuppressive medications in addition to antibiotics. Use of immunosuppressives carries the risk of sepsis in a setting of established infection. Defining the histology of the renal lesion in patients with infective endocarditis, ANCA formation, and renal involvement is required to identify patients who can potentially profit from the addition of immunosuppressive medication to antibiotics. Categories: Internal Medicine, Cardiology, Pathology