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Microscopic polyangiitis

Key sources
The following summarized guidelines for the evaluation and management of microscopic polyangiitis are prepared by our editorial team based on guidelines from the European League Against Rheumatism (EULAR 2023), the Canadian Vasculitis Research Network (CanVasc 2023; 2021), the Kidney Disease: Improving Global Outcomes Foundation (KDIGO 2021), the Vasculitis Foundation (VF/ACR 2021), and the Single Hub and Access Point for Pediatric Rheumatology in Europe (SHARE initiative 2019).


1.Classification and risk stratification

Severity assessment: stratify patients with newly diagnosed or relapsing ANCA-associated vasculitides according to the extent and severity of the disease to tailor treatment accordingly.
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2.Diagnostic investigations

Antineutrophil cytoplasmic antibodies: as per EULAR 2023 guidelines, obtain both proteinase 3-ANCA and myeloperoxidase-ANCA testing, with a high-quality antigen-specific assay as the primary method of testing, in patients with signs and/or symptoms raising suspicion of a diagnosis of ANCA-associated vasculitis.

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  • Serum immunoglobulins

3.Diagnostic procedures

Biopsy: as per EULAR 2023 guidelines, perform biopsies to assist in establishing a new diagnosis of ANCA-associated vasculitis and for further evaluation of patients suspected of having relapsing vasculitis.

4.Medical management

General principles
As per EULAR 2023 guidelines:
Offer multidisciplinary management in centers with, or with ready access to, expertise in vasculitis in patients with ANCA-associated vasculitis.
Offer the best care based on shared decision-making between the patient and the physician, taking efficacy, safety, and costs into account, in patients with ANCA-associated vasculitis.

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  • Induction of remission (non-severe)

  • Induction of remission (severe)

  • Induction of remission (avacopan)

  • Induction of remission (IVIG and plasma exchange)

  • Maintenance of remission

  • Anticoagulant therapy

5.Therapeutic procedures

Plasma exchange
As per EULAR 2023 guidelines:
Consider performing plasma exchange as part of therapy to induce remission in patients with MPA with a serum creatinine > 300 mcmol/L due to active glomerulonephritis.
Do not perform plasma exchange routinely for the treatment of alveolar hemorrhage in patients with MPA.

6.Surgical interventions

Kidney transplantation: as per KDIGO 2021 guidelines, delay kidney transplantation until patients are in complete clinical remission for ≥ 6 months. Do not delay transplantation because of the persistence of ANCA.

7.Specific circumstances

Pediatric patients, diagnosis and classification
Recognize that there are no validated diagnostic criteria for MPA.
Use the Chapel Hill 2012 criteria for MPA in epidemiological and/or clinical studies.

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  • Pediatric patients (ANCA testing)

  • Pediatric patients (diagnostic imaging)

  • Pediatric patients (biopsy)

  • Pediatric patients (treatment)

  • Pregnant patients

  • Patients with renal involvement

  • Patients with respiratory tract involvement (topical therapy)

  • Patients with respiratory tract involvement (plasma exchange)

8.Patient education

General counseling: provide patients with ANCA-associated vasculitis education focusing on the impact of ANCA-associated vasculitis and its prognosis, key warning symptoms, and treatment (including treatment-related complications).

9.Preventative measures

Prophylaxis for Pneumocystis jirovecii pneumonia: administer TMP/SMX for prophylaxis against P. jirovecii pneumonia and other infections in patients with ANCA-associated vasculitis receiving rituximab, cyclophosphamide, and/or high doses of corticosteroids.

10.Follow-up and surveillance

Serial clinical assessment
As per EULAR 2023 guidelines:
Obtain periodic assessment for treatment-related adverse effects and comorbidities in patients with ANCA-associated vasculitis. Offer prophylaxis and lifestyle advice to reduce treatment-related complications and other comorbidities.
Obtain structured clinical assessment, rather than ANCA and/or CD19-positive B cell testing alone, to inform decisions on changes in treatment in patients with ANCA-associated vasculitis.

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  • Serial laboratory assessment

  • Management of refractory disease

  • Management of relapse (immunosuppressants)

  • Management of relapse (avacopan)