Myeloperoxidase Antineutrophil Cytoplasmic Antibody-Associated Renal-Limited Vasculitis in a Young Adult Woman.

Yukihiro Otaka,Daiki Uchida,Nobuyoshi Ishiyama,Keiko Kawai-Kowase,Kinue Shimizu-Arii

doi:10.7759/cureus.21654

Abstract

Antineutrophil cytoplasmic antibody (ANCA)-associated renal-limited vasculitis (RLV) is a minor subtype of small vessel vasculitis characterized by the inflammation of blood vessels, tissue damage, and loss of renal function localized in the kidney without systemic involvements. Here, we report a case of myeloperoxidase (MPO) ANCA-associated RLV in a young adult woman in Japan presenting chronic hematuria and newly overt proteinuria. Percutaneous renal biopsy revealed focal fibro-cellular crescent glomerulonephritis and the absence of other small vasculitides, tubular atrophy, and interstitial fibrosis. Therapeutic intravenous methylprednisolone pulse followed by oral prednisolone was administered as a remission induction. The patient’s serum MPO-ANCA level gradually decreased, coinciding with dramatic changes in proteinuria and hematuria after therapeutic glucocorticoid administration. Renal function was maintained within the normal range, and disease activity was well-tolerated throughout the follow-up period for more than 14 weeks. While the incidence of RLV is rare among younger patients, it occurs with asymptomatic hematuria and proteinuria, which is important in differentiating RLV from typical glomerulonephritis. The overall prognosis of ANCA-associated RLV potentially depends on the severity of extrarenal involvements. Early diagnosis, appropriate treatment, and regular maintenance are essential for controlling and treating RLV. Due to the nontypical case presented here, further investigation is recommended to improve the diagnosis strategies and treatment options for this disease.

Highlights

Antineutrophil cytoplasmic antibody (ANCA)-associated renal-limited vasculitis (RLV) is a minor subtype of small vessel vasculitis characterized by the inflammation of blood vessels, tissue damage, and loss of renal function localized in the kidney without systemic involvements
While the incidence of RLV is rare among younger patients, it occurs with asymptomatic hematuria and proteinuria, which is important in differentiating RLV from typical glomerulonephritis
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease characterized by the inflammation of blood vessels, endothelial injury, and damage of surrounding tissues [1]

Summary

Introduction

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease characterized by the inflammation of blood vessels, endothelial injury, and damage of surrounding tissues [1]. ANCA-associated renal-limited vasculitis (RLV) is a small vessel vasculitis localized in the kidney without systemic involvement [1]. ANCA-associated RLV showed relatively better outcomes compared with typical MPA or granulomatosis presenting with polyangiitis in terms of renal relapse, long-term dialysis, kidney transplantation, and mortality [3]. Proteinuria and hematuria were dramatically reduced after glucocorticoid administration (Figures 2a-2b), serum MPO-ANCA remained well above the normal limit; the titer progressively decreased along with maintenance therapy (Figure 2c). During the follow-up period over the 14 weeks, the estimated glomerular filtration rate was maintained at the normal range between 90 and 110 mL/min/1.73 m2, and the reassessed BVAS-2003 was 5, accorded by the still persistent proteinuria and microscopic hematuria at week 15

Discussion

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Disclosures