What is the initial workup and treatment for vasculitis?

Initial Workup and Treatment for Vasculitis

The initial workup for vasculitis should include comprehensive disease assessment with validated activity scores, specific laboratory tests including ANCA, inflammatory markers, and appropriate imaging or biopsy of affected tissues, followed by prompt initiation of high-dose glucocorticoids with or without immunosuppressive agents based on disease severity classification.

Diagnostic Workup

Classification and Assessment

• Patients with suspected vasculitis should be categorized according to vessel size (large, medium, or small) and disease severity to guide appropriate management 1
• Disease activity should be assessed using validated tools such as Birmingham Vasculitis Activity Score (BVAS), Disease Extent Index, Vasculitis Damage Index, and Short Form 36 1
• Patients with ANCA-associated vasculitis (AAV) should be categorized as: localized, early systemic, generalized, severe, or refractory disease 1

Laboratory Testing

• ANCA testing (including indirect immunofluorescence and ELISA) should be performed in appropriate clinical contexts 1
• Basic laboratory tests should include:
  • Complete blood count with differential
  • Comprehensive metabolic panel including renal function
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 1
  • Urinalysis with microscopic examination and quantification of proteinuria 1
• Serial ANCA measurements are recommended in clinical trials but have limited value in routine clinical practice for predicting disease activity 1

Imaging and Biopsy

• Biopsy of affected tissue is strongly recommended to confirm diagnosis and assist in further evaluation 1
• For giant cell arteritis (GCA), temporal artery biopsy should be performed but should not delay treatment initiation 1
  • Biopsy sample should be at least 1 cm in length 1
  • Contralateral biopsy is not routinely indicated 1
• For Takayasu arteritis, thorough clinical and imaging assessment of the arterial tree is recommended 1
• For CNS vasculitis, MRI with specialized sequences (ADC maps, diffusion, gradient echo) is the investigation of choice 2
• For peripheral nerve involvement, electromyography with neurophysiological tests and possibly nerve biopsy should be performed 1

Treatment Approach

Initial Treatment Based on Disease Classification

Large Vessel Vasculitis (GCA, Takayasu Arteritis)

• Early initiation of high-dose glucocorticoid therapy is recommended for induction of remission 1
  • Initial dose of prednisolone: 1 mg/kg/day (maximum 60 mg/day) 1
  • Maintain high-dose for one month, then taper gradually 1
• Consider immunosuppressive agents as adjunctive therapy 1
• For GCA, low-dose aspirin (75-150 mg/day) is recommended for all patients without contraindications 1

Small and Medium Vessel Vasculitis (ANCA-Associated Vasculitis)

• For generalized disease: Combination of cyclophosphamide (intravenous or oral) and glucocorticoids 1
  • Oral cyclophosphamide: 2 mg/kg/day (max 200 mg/day) with prednisolone 1 mg/kg/day (max 60 mg/day) 1
  • Pulsed cyclophosphamide may have lower risk of side effects but higher risk of relapse 1
• For severe disease (renal or vital organ failure): Consider addition of plasmapheresis 1
• For non-organ threatening disease: Methotrexate with glucocorticoids may be used as a less toxic alternative 1
• For refractory disease: Consider rituximab, which has shown 91% remission rate in open-label trials 1, 3

Special Considerations

• For HCV-associated cryoglobulinemic vasculitis: Antiviral therapy is recommended 1
• For CNS vasculitis: Combination of steroids and cyclophosphamide is generally recommended, with rituximab as an alternative option 2
• Prophylaxis against Pneumocystis jiroveci and osteoporosis should be considered for patients on immunosuppressive therapy 1
• All patients should have bone protection therapy in accordance with local guidelines 1

Monitoring and Follow-up

• Clinical monitoring aided by inflammatory markers should inform treatment decisions 1
• Regular assessment of disease activity using structured clinical examination and validated tools 1
• Monitor for drug toxicity:
  • Acute fall in white cell count or progressive leucopenia may require dose adjustment or discontinuation of immunosuppressive drugs 1
  • Periodic assessment of blood sugar for patients on glucocorticoid therapy 1
  • Renal function monitoring for appropriate dose adjustment 1

Common Pitfalls and Caveats

• Do not delay treatment with high-dose glucocorticoids when GCA is strongly suspected, even before biopsy confirmation 1
• Biopsy should be performed within 1-2 weeks of starting glucocorticoid therapy 1
• Normal ESR or CRP should raise suspicion for alternative diagnoses in suspected GCA 1
• Differentiation between infection and active vasculitis can be challenging but is crucial, as inappropriate immunosuppression can be fatal 4
• Drug-induced vasculitis should be considered in the differential diagnosis, as withdrawal of the offending agent may be sufficient for resolution without requiring immunosuppression 5