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Abstract: PO1757

Rare Case of Myeloperoxidase-ANCA-Positive Polyarteritis Nodosa

Session Information

Category: Trainee Case Report

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Makadia, Bhaktidevi, Stony Brook University Hospital, Stony Brook, New York, United States
  • Mallipattu, Sandeep K., Stony Brook University Hospital, Stony Brook, New York, United States
  • Revelo Penafiel, Monica Patricia, University of Utah Health, Salt Lake City, Utah, United States
Introduction

Polyarteritis Nodosa (PAN) is systemic necrotizing vasculitis involving medium-size vessels. PAN is typically not associated with positive antineutrophil cytoplasmic antibodies (ANCA) titter. Here, we report a patient who presented with abdominal pain, hematuria, sub-nephrotic range proteinuria, acute kidney injury (AKI) with high MPO ANCA titer who was diagnosed with PAN.

Case Description

40-year-old male with asthma presented with abdominal pain, generalized weakness and myalgia, weight loss of 25 pounds over the last 2 months. Two weeks prior to presentation, patient was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA) and started on prednisone at the outpatient clinic. Physical exam was significant for hypertension, abdominal tenderness and petechial rash in the lower extremities. Laboratory findings were significant for serum creatinine 1.6 mg/dl, ESR 93 mm/hr, CRP 25 mg/dl, ANCA titer 1:160 with MPO – 46 units. Urinalysis revealed 28 RBC/hpf with urine protein/creatine - 1.4 g/g. Esophagogastroduodenoscopy and skin biopsy of petechial rash were negative for vasculitis. Kidney biopsy reveled focal arterial fibrinoid necrosis with mixed interstitial inflammatory infiltrate consistent with necrotizing arteritis involving predominantly medium size arteries, leading to a diagnosis of PAN (fig 1). Patient was treated with pulse dose methylprednisolone and cyclophosphamide for PAN with maintenance prednisone.

Discussion

PAN is a rare disease involving multiple organ systems, including the kidney, and is typically not associated with a positive ANCA titer observed in small-vessel vasculitis. In the largest database of biopsy-proven PAN (n=348), French Vasculitis Study Group, 253 patients had ANCA titer done at the time of diagnosis with PAN, and all were negative. Kidney biopsy revealed a rare diagnosis of MPO-ANCA+ PAN which was critical to determining the management in this patient.

Arrow Shows necrotizing arteritis of medium size arteries