vasculitisrelated

Vasculitis refers to a group of disorders characterized by inflammation of blood vessel walls, which can cause vessel narrowing, occlusion, and tissue injury. The term vasculitis-related describes manifestations or complications that arise from vasculitis or its treatment.

Classification typically follows vessel size: large-vessel vasculitis includes giant cell arteritis and Takayasu arteritis; medium-vessel vasculitis includes polyarteritis nodosa and Kawasaki disease; small-vessel vasculitis includes granulomatosis with polyangiitis (formerly Wegener), microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis (Churg-Strauss), and IgA vasculitis. Other schemes distinguish mechanisms such as ANCA-associated vasculitides, immune complex–mediated vasculitis, and eosinophilic vasculitis.

Pathophysiology involves immune-mediated inflammation of vessel walls that can lead to leakage, thrombosis, and organ ischemia. ANCA antibodies can activate neutrophils and monocytes, immune complexes can deposit in vessels, and complement activation may contribute to tissue injury. The specific pathways vary by type.

Clinical features are highly variable and depend on the organs affected. Common systemic symptoms include fever, weight loss, and fatigue. Organ-specific manifestations may include skin purpura, mononeuritis multiplex, nasal or sinus involvement, cough or hemoptysis, renal impairment with proteinuria or hematuria, and abdominal pain from mesenteric vessel involvement.

Diagnosis combines clinical assessment with laboratory tests (elevated ESR/CRP, complete blood count, urinalysis, kidney function, autoantibodies such as ANCA), imaging (ultrasound, CT/MRI, PET), and tissue biopsy when feasible, which provides a definitive diagnosis in many cases.

Treatment usually starts with systemic corticosteroids and is often complemented by immunosuppressants such as cyclophosphamide, azathioprine, methotrexate, or rituximab, depending on the type and severity. Plasma exchange may be used in select ANCA-associated vasculitides. Infection prevention and vaccination are important due to immunosuppressive therapy. Disease activity requires ongoing monitoring for relapse and treatment-related adverse effects.