Vasculitis Management

Introduction

• Systemic vasculitis is a complex disease characterized by inflammation and damage to blood vessel walls, involving immune mechanisms, and leading to organ dysfunction and potentially life-threatening complications, as supported by the European League Against Rheumatism and the American College of Rheumatology 1, 2

Diagnosis and Assessment

• Biopsy of affected tissue is strongly recommended to establish diagnosis, according to the European League Against Rheumatism, in patients with suspected vasculitis, with a diagnostic yield of over 70% when properly targeted 3, 4, 5
• Initial laboratory investigations should include complete blood count with differential, comprehensive metabolic panel, inflammatory markers (ESR, CRP), urinalysis with microscopic examination, ANCA testing (both MPO-ANCA and PR3-ANCA) 5
• ANCA testing should be considered in any patient with suspicious clinical manifestations, particularly nasal crusting and bleeding, especially if they feel disproportionally unwell, as recommended by the American College of Rhinology 6
• A negative ANCA does not exclude vasculitis, particularly in limited forms of disease or following corticosteroid therapy, as noted by the American College of Rhinology 6
• Select imaging based on suspected vessel size, including:

• The Birmingham Vasculitis Activity Score (BVAS) is a recommended measure of disease activity, according to the American College of Rhinology 6
• The Vasculitis Damage Index (VDI) is a useful tool for assessing disease damage, as noted by the American College of Rhinology 6
• Comprehensive disease assessment requires disease activity measurement (Birmingham Vasculitis Activity Score), Disease Extent Index, Vasculitis Damage Index, and functional assessment (Short Form 36), as suggested by the European League Against Rheumatism, with a strength of evidence level II 1

Treatment

• The European League Against Rheumatism recommends a combination of glucocorticoids and either cyclophosphamide or rituximab for remission induction in patients with vasculitis 3
• The American College of Rheumatology recommends high-dose corticosteroids, such as prednisone 1 mg/kg/day, combined with immunosuppressants like cyclophosphamide or rituximab, for the treatment of severe or systemic vasculitis, with cyclophosphamide dosed up to 2 mg/kg/day oral or intermittent IV and rituximab dosed at 375 mg/m² IV weekly for 4 doses or 1,000 mg on days 1 and 15 9
• Treatment should not be delayed while waiting for biopsy results in ANCA-positive patients with compatible clinical presentation, especially in rapidly deteriorating patients, as supported by the European League Against Rheumatism 2, 10
• Continue treatment with low-dose glucocorticoids and either azathioprine, rituximab, methotrexate, or mycophenolate mofetil, as recommended by the European League Against Rheumatism, to maintain remission 3
• For patients with severe renal involvement, consider plasma exchange, as recommended by the European League Against Rheumatism, for patients with serum creatinine ≥500 mmol/L (5.7 mg/dL) due to rapidly progressive glomerulonephritis 3

Monitoring and Prophylaxis

• Perform structured clinical assessment, rather than ANCA testing, to guide treatment decisions, as recommended by the European League Against Rheumatism and the American College of Rheumatology 3, 9
• Provide Pneumocystis jirovecii pneumonia prophylaxis for patients receiving rituximab or cyclophosphamide, as recommended by the American College of Rheumatology 9
• Monitor inflammatory markers and renal function every 1-3 months, as recommended by the European League Against Rheumatism, to screen for disease activity and drug toxicity 3
• Regular monitoring should include renal function tests, urinalysis with microscopic examination, inflammatory markers (ESR, CRP), and ANCA levels, which can be useful for predicting relapse in some patients, according to the American College of Rhinology 6
• Regular monitoring should include renal function tests, urinalysis with microscopic examination, inflammatory markers, ANCA levels, and complete blood count with differential, as recommended by the American College of Rheumatology and the National Kidney Foundation, with a strength of evidence level II 1, 3

Special Considerations

• Patients with Behçet's disease and c-ANCA positivity should be managed in close collaboration with, or at, centers of expertise in vasculitis, as recommended by the European League Against Rheumatism 3
• Investigate persistent unexplained hematuria, especially in patients with prior cyclophosphamide exposure, to screen for bladder cancer, as recommended by the European League Against Rheumatism 3
• The risk of bleeding following percutaneous renal biopsy is higher in patients treated with plasma exchange, in older patients, those with increased systolic blood pressure, and worse renal function, according to the European League Against Rheumatism 3
• Pauci-immune vasculitis, including GPA, MPA, and EGPA, is characterized by ANCA positivity in most cases, and often presents with necrotizing glomerulonephritis, microscopic hematuria, red cell casts, moderate proteinuria, and rapidly declining glomerular filtration rate, with a prevalence of 10% for diffuse alveolar hemorrhage in AAV patients, as reported by the European League Against Rheumatism 2
• The activity state of systemic vasculitis can be classified into remission, response, relapse, refractory disease, and low-activity disease, based on the presence and severity of active inflammation, as defined by the American College of Rheumatology, with the following table summarizing the activity states and their pathophysiological basis: