Overlap Syndrome in Late-Onset Systemic Lupus Erythematosus With Lupus Nephritis and MPO-ANCA Pauci-Immune Glomerulonephritis and Tuberculosis: An Uncommon Association.

Systemic lupus erythematosus is a systemic autoimmune pathology that generally presents in young people and manifests acutely, while its late presentation in people over 50 years of age is rare and insidious. Vasculitis is a pathology that affects any vessel producing fibrinoid necrosis, and presents with a positive antineutrophil cytoplasmic antibody. The concomitance of these two entities is rare and leads to worse clinical outcomes. We present a 73-year-old female patient who presented with rapidly progressive glomerulonephritis requiring renal replacement therapy, pulmonary tuberculosis, late-onset lupus erythematosus with lupus nephritis, and a positive result for neutrophil cytoplasmic antibody. An immune-mediated extracapillary proliferative glomerulonephritis was found when the biopsy was performed, with obvious signs of vasculitis, an overlap syndrome was found between these entities. She was initially treated with antituberculosis therapy, boluses of methylprednisolone and continued with intermittent renal replacement therapy; however, due to the severity of his pathologies, she had a fatal outcome. The concomitance between these autoimmune pathologies is unusual; there is a late-onset overlap syndrome between lupus nephritis accompanied by myeloperoxidase-antineutrophil cytoplasmic antibody and pauci-immune glomerulonephritis. The dual presentation establishes clinical challenges for its diagnosis as well as the initiation of immunosuppressive therapy when there are additional infectious pathologies.