From the Guidelines
Biopsy is strongly recommended in suspected ANCA vasculitis to confirm diagnosis, particularly when clinical presentation and serologic testing are inconclusive, as stated in the 2024 EULAR recommendations for the management of ANCA-associated vasculitis 1. The optimal tissue for biopsy depends on organ involvement, with renal biopsy recommended for patients with active urinary sediment or declining kidney function, lung biopsy for pulmonary infiltrates or nodules, skin biopsy for cutaneous manifestations, and nerve biopsy for neuropathy.
- Key considerations for biopsy include:
- Performing biopsy before initiating immunosuppressive therapy whenever possible, as treatment can alter histopathological findings 1
- Urgent biopsy is warranted in rapidly progressive glomerulonephritis or diffuse alveolar hemorrhage
- Even with positive ANCA serology, biopsy remains important as ANCA positivity can occur in other conditions Histopathological findings typically show necrotizing vasculitis with little or no immune deposits (pauci-immune) in small vessels, with features varying by specific syndrome (granulomatosis with polyangiitis, microscopic polyangiitis, or eosinophilic granulomatosis with polyangiitis) 1. Biopsy results guide treatment decisions, help assess disease severity, and provide prognostic information, making it a crucial diagnostic tool in the management of ANCA vasculitis 1.
From the Research
ANCA Vasculitis Indication of Biopsy
- ANCA-associated vasculitis is a group of rare, primary, systemic necrotizing small-vessel vasculitides, and biopsy may be necessary for confirmation of the diagnosis 2.
- A structured clinical assessment should be conducted, evaluating all the organs possibly involved, and tissue biopsy may be necessary for confirmation of the diagnosis 2.
- The diagnosis of ANCA-associated vasculitis is based on clinical manifestation, ANCA-testing, and histology 3.
- Biopsy-proven pauci-immune GN is one of the indicators of renal involvement in ANCA-associated vasculitis 4, 5.
- Renal biopsy is an important tool for diagnosing and managing ANCA-associated vasculitis, especially in patients with renal involvement 4, 5, 6.
Treatment and Management
- Rituximab is a preferable option for both induction and maintenance of remission in ANCA-associated vasculitis 2, 6.
- Cyclophosphamide and glucocorticoids have been the cornerstone of remission-induction therapy for severe ANCA-associated vasculitis, but rituximab may be safer and more effective 4, 5, 6.
- The treatment of ANCA-associated vasculitis has changed from a standardized protocol to an individualized less toxic strategy taking into consideration disease severity, organ manifestation, age of the patient, and individual risk factors 3.
Clinical Characteristics
- ANCA-associated vasculitis can present with a range of clinical characteristics, including multisystem organ dysfunction, chronic recurrent rhinosinusitis, cavitated lung nodules, palpable purpura, and acute kidney injury 2.
- The clinical diagnosis and ANCA specificity are important factors in determining the treatment approach for ANCA-associated vasculitis 2, 3.