An Unusual Presentation of Renal Failure: A Case of Myeloperoxidase-Antineutrophil Cytoplasmic Antibody (MPO-ANCA) Vasculitis.

Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) vasculitis manifests as a neutrophilic inflammation impacting small vessels across multiple organs, notably the lungs, kidneys, and skin. We present a unique case of MPO-ANCA vasculitis in a 77-year-old female characterized by glomerulosclerosis, rapidly progressive renal failure necessitating hemodialysis (HD), bullous skin lesions, and hypoxic respiratory failure. The patient, who had a history of type 2 diabetes, presented with progressive dyspnea, hypoxia, and acute kidney injury superimposed on chronic kidney disease (CKD) progressing to renal failure requiring dialysis. A renal biopsy highlighted globally sclerosed glomeruli, interstitial fibrosis, and tubular atrophy, along with increased immunoglobulin M (IgM) deposits on immunofluorescence, differing from typical findings. Prompt initiation of prednisone led to respiratory and cutaneous improvement; however, despite therapy, extensive renal damage led to the permanent requirement of dialysis.  MPO vasculitis primarily targets small vessels, frequently affecting kidneys, with only a subset of patients progressing rapidly to end-stage renal failure necessitating HD, as observed in our case. Contrary to classical histopathological patterns, our patient exhibited augmented IgM deposits. Left untreated, MPO vasculitis with renal involvement poses a mortality risk of up to 90%, underscoring the significance of prompt detection and corticosteroid intervention to avert renal failure and improve patient outcomes. Early recognition and timely treatment are pivotal in mitigating the dire consequences of this condition, emphasizing the importance of considering MPO vasculitis in patients with rapidly deteriorating renal function.