A Rare Case of Overlapping Syndrome of ANCA-Associated Glomerulonephritis and Systemic Lupus Erythematosus

Introduction: Two very interesting rheumatologic diagnoses include Systemic Lupus Erythematosus (SLE) and Anti-Neutrophil Cytoplasmic Antibody (ANCA)-negative Vasculitis. It is rare to see these two conditions diagnosed in the same patient. This case analyzes the complex interactions between these two disease states. Case: This is the case of a 69 year old female who presented with shortness of breath, hematuria, and renal failure. Lab work was significant for elevated ANA (1:1280), positive double-stranded DNA antibody, normal complement levels and a negative Vasculitis panel. Renal biopsy was consistent with ANCA-associated Vasculitis (AAV). Thus the patient met diagnostic criteria for both SLE and AAV and was treated accordingly. Conclusion: A review of the literature reveals that these typically separate disease entities when diagnosed together may actually represent a completely new, overlapping syndrome. This case is unique in that there have not been any other cases of a simultaneous diagnosis of SLE and ANCA-negative Vasculitis without evidence of lupus nephritis reported in the literature. A deeper understanding of the mechanism driving these rare diseases can lead to improved prognostication and treatment of these conditions. Keywords: Systemic lupus erythematosus; ANCA; Vasculitis; Autoimmun