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Abstract: PO1492

A Case of ANCA-Associated Vasculitis (AAV) in Mixed Connective Tissue Disease (MCTD) Manifesting as Pulmonary Renal Syndrome

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation


  • Chandra, Samira Zannat, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
  • Krause, Michelle W., University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Newly diagnosed microscopic polyangiitis (MPA) with positive anti-MPO in the background of MCTD is quite uncommon. Not every patient with positive Anti-MPO titers develops clinical manifestations of microscopic polyangiitis. Prompt diagnosis and early intervention is necessary to prevent end organ damage.

Case Description

56-year-old malnourished AAF with history of MCTD (diffuse systemic sclerosis and SLE since 2005), restrictive lung disease, recurrent URI, CKD stage 3, diastolic heart failure with moderate MR, and pulmonary hypertension was transferred to ICU for worsening pneumonia and acute on chronic kidney injury. Admission serum creatinine was 2.6mg/dl (baseline s. creat 2.0mg/dl) which increased to 4.7 mg/dl during the hospital course. Lab was significant for Hgb 6.3 gm/dl, ESR 120 mm and CRP 30. Non-contrast CT chest showed bilateral interstitial opacities with superimposed consolidation. Evaluation for infectious etiologies and malignancies were negative. Bronchoscopy was concerning for diffuse alveolar hemorrhage. UA was positive for large blood with proteinuria >200mg/dl. Vasculitis work up came back positive for p- ANCA (1:1280) and anti-MPO 4 AU/ml (reference range <19) but negative for anti-PR3 and anti-GBM antibody. Renal biopsy revealed focal crescentic and necrotizing glomerulonephritis with severe interstitial fibrosis and tubular atrophy indicating MPA. Patient was treated with pulse steroid and plasma pheresis initially, later received Rituximab. Patient improved clinically with therapy. Later, serum creatinine plateaued around 3.6 with eGFR 15.6 indicating patient’s CKD had progressed to advanced CKD stage 4/ 5.


Though the presence of AAV is not common in MCTD, this case illustrates the importance of considering AAV for worsening pulmonary and renal function in overlap syndrome. Microscopic polyangiitis is one of the most common cause of pulmonary- renal syndrome, often manifested as diffuse alveolar hemorrhage and RPGN. Prompt diagnosis and early intervention can dramatically improve the patient outcome.