Vasculitis Classification and Treatment
Vasculitis should be classified according to vessel size (large, medium, small) as per the 2012 Chapel Hill Consensus Conference nomenclature, with treatment tailored to the specific type and severity of vasculitis to reduce morbidity and mortality. 1
Classification of Vasculitis
The classification of vasculitis is challenging due to the heterogeneous nature of these conditions. The most widely accepted classification system is based on the size of affected blood vessels:
Based on Vessel Size
Large vessel vasculitis: Affects the aorta and its major branches 1
- Giant cell arteritis (GCA) - typically affects patients >50 years old
- Takayasu arteritis (TAK)
Medium vessel vasculitis: Affects main visceral arteries and initial branches 1
- Polyarteritis nodosa (PAN)
- Kawasaki disease
Small vessel vasculitis: Affects intraparenchymal vessels 1
- ANCA-associated vasculitis:
- Granulomatosis with polyangiitis (GPA, formerly Wegener's)
- Microscopic polyangiitis (MPA)
- Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss)
- Immune complex small vessel vasculitis:
- Cryoglobulinemic vasculitis
- IgA vasculitis (Henoch-Schönlein purpura)
- ANCA-associated vasculitis:
Variable vessel vasculitis: Can affect vessels of any size 1
- Behçet's disease
- Cogan's syndrome
Other Classification Considerations
- Primary vs. Secondary: Primary vasculitis occurs independently, while secondary vasculitis is associated with another condition 1, 2
- Single-organ vs. Systemic: Vasculitis may be limited to a single organ or involve multiple systems 1
Treatment of Vasculitis
Treatment approaches vary based on the type of vasculitis, severity, and organ involvement:
General Treatment Principles
- Treatment goals: Induce remission, prevent relapse, minimize treatment toxicity 1
- Severity assessment: Evaluate extent of organ involvement to determine treatment intensity 1
Treatment by Vasculitis Type
ANCA-Associated Vasculitis (GPA, MPA, EGPA)
Induction Therapy for Severe Disease:
- First-line: Rituximab (375 mg/m² weekly for 4 weeks) or cyclophosphamide plus high-dose corticosteroids 3
Maintenance Therapy:
- Options include: Rituximab (500 mg every 6 months), azathioprine, or methotrexate 3
- Maintenance therapy typically continues for 18-24 months 1
For EGPA Specifically:
- Consider mepolizumab for eosinophilic manifestations 1
- ANCA status influences treatment approach (ANCA-positive patients more likely to need aggressive immunosuppression) 1
Large Vessel Vasculitis (GCA, Takayasu)
- Initial treatment: High-dose corticosteroids (prednisone 1 mg/kg/day) 1
- Steroid-sparing agents: Consider tocilizumab, methotrexate, or leflunomide 1
- Monitoring: Regular clinical assessment and vascular imaging 1
Medium Vessel Vasculitis (PAN, Kawasaki)
- PAN: Cyclophosphamide plus corticosteroids; consider plasma exchange for severe disease 1
- Kawasaki disease: Intravenous immunoglobulin plus aspirin 2
Special Considerations
- Infection prophylaxis: Consider Pneumocystis jirovecii pneumonia prophylaxis with trimethoprim-sulfamethoxazole during immunosuppressive therapy 1
- Monitoring: Regular assessment of disease activity, treatment toxicity, and infection 1
- Pregnancy: Modify treatment regimen to avoid teratogenic medications 1
Common Pitfalls and Caveats
- Diagnostic challenges: Vasculitis can mimic infection, malignancy, or other inflammatory conditions; biopsy is recommended when feasible but not always essential 1
- Treatment toxicity: Balance between disease control and treatment-related complications 1
- Relapse risk: Up to 50% of patients may relapse, requiring long-term monitoring 3
- Comorbidities: Consider cardiovascular risk factors, osteoporosis prevention, and infection risk 1