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Abstract: PO1955

Rare Case of Silicosis-Induced Pauci-Immune Glomerulonephritis

Session Information

Category: Trainee Case Report

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Venkataraman, Sandheep, University of Colorado, Denver, Colorado, United States
  • Ray, Matthew, University of Colorado, Denver, Colorado, United States
  • Dylewski, James F., University of Colorado, Denver, Colorado, United States
Introduction

Pauci-immune glomerulonephritis(GN) caused by ANCA was first described in 1982. Most cases are idiopathic, however, ANCA vasculitis may induced due to certain exposures. Here we report a case of ANCA vasculitis associated with pulmonary silicosis.

Case Description

A 37-year-old man with no prior history presented with anorexia, weight loss, fatigue, and arthralgias for 6 months. He was employed as a sandblaster, stonecutter, and as a mason. On initial exam he was found to have dactylitis and Raynaud’s phenomenon. His presenting creatinine(Cr) was 2.9 mg/dL with urinalysis showing 3+ blood and 1.2 gm proteinuria. Renal ultrasound demonstrated enlarged kidneys bilaterally. Notable serologies were ANA positive 1:1280, p-ANCA positive 1:2560, C3 77 mg/dL, C4 6 mg/dL, and MPO at 78 AU/ml. CT Chest revealed innumerable pulmonary nodules, extensive fibrosis, and mediastinal lymph nodes with eggshell calcifications. Infectious workup was negative. Transbronchial biopsy demonstrated collection of histiocytes containing black pigment without granulomas. Kidney biopsy showed necrotizing crescentic GN, with marked interstitial inflammation and focal intralobular vessel infiltrates. IF and EM was negative, consistent with pauci-immune ANCA vasculitis. Given his history and presentation, he was diagnosed with silica-induced ANCA vasculitis. He was treated with 3 days of IV methylprednisolone, followed by a rapid prednisone taper. He also received IV Rituximab 1 gm on days 0 and 14, plus IV cyclophosphamide 500 mg every 2 weeks for 6 doses starting on day 0. The patient responded well with Cr improving to 1.0 and decreased proteinuria. Unfortunately he relapsed 3 months after last rituximab dose.

Discussion

Silica exposure is most often associated with pulmonary disease but there have been case reports of RPGN associated with it too. The majority of these patients were MPO positive. T-cell dysregulation and endothelial damage from PMNL free radical generation is a proposed mechanism for this disease. Duration and intensity of silica exposure are known risk factors. In addition to pulmonary-renal symptoms, these patients may have systemic manifestations of lupus, rheumatoid arthritis, scleroderma, or dermatomyositis. More research is needed to further understand the management of these patients. This patient represents a rare case of silica-induced ANCA pulmonary-renal vasculitis.