What is the workup and treatment for large vessel vasculitis?

Workup and Treatment for Large Vessel Vasculitis

The diagnostic workup for large vessel vasculitis should include thorough vascular imaging, laboratory assessment, and temporal artery biopsy for GCA, followed by treatment with high-dose glucocorticoids and consideration of tocilizumab as adjunctive therapy to improve outcomes and reduce steroid exposure.

Diagnostic Workup

Clinical Assessment and Laboratory Testing

• Evaluate for constitutional symptoms (fever, weight loss, fatigue)
• Check for vascular symptoms (claudication, bruits, pulse deficits, asymmetric blood pressures)
• Laboratory markers:
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) - highly sensitive but not specific 1
  • Complete blood count - assess for anemia, thrombocytosis
  • Renal function tests and urinalysis - rule out other vasculitides
  • Liver function tests - baseline before treatment 1

Vascular Imaging

• For Takayasu arteritis: Thorough imaging assessment of the arterial tree is mandatory 1

  • MRI/MRA: Preferred for initial assessment and follow-up
  • PET-CT: Highly sensitive for detecting active inflammation, especially in early disease 2
  • Conventional angiography: Consider if advanced imaging unavailable

• For Giant Cell Arteritis (GCA):

  • Temporal artery ultrasound: 88% sensitive and 97% specific for temporal arteritis 1
  • Vascular imaging (MRI, PET-CT) for large vessel involvement assessment

Biopsy

• Temporal artery biopsy: Gold standard for GCA diagnosis 1
  • Should be performed whenever GCA is suspected
  • Obtain at least 1 cm sample length
  • Biopsy should not delay treatment initiation
  • Can remain positive up to 1-2 weeks after starting glucocorticoids 1

Treatment Algorithm

Initial Treatment

1. Immediate high-dose glucocorticoid therapy 1

   • Prednisone 40-60 mg/day (1 mg/kg/day, maximum 60 mg/day)
   • Maintain high dose for 1 month, then taper gradually
   • For GCA with visual symptoms: Consider initial IV methylprednisolone

2. Consider adjunctive therapy at initiation 1, 3

   • Tocilizumab: FDA-approved for GCA 3

     • Subcutaneous injection: 162 mg weekly or every other week based on weight
     • Significantly reduces relapse rates and cumulative steroid exposure 4, 5

   • For GCA: Methotrexate (10-15 mg/week) can be considered as alternative 1

   • For Takayasu arteritis: Methotrexate (20-25 mg/week) or azathioprine (2 mg/kg/day) 1, 4

Glucocorticoid Tapering

• Taper to 15-20 mg/day within 2-3 months
• Aim for ≤5 mg/day after 1 year 1
• Monitor for disease activity during tapering

Management of Relapses

• Major relapse (ischemic symptoms or progressive vascular inflammation):

  • Reinstitute high-dose glucocorticoids (40-60 mg/day) 1
  • Add or modify adjunctive therapy if not already prescribed 1

• Minor relapse (isolated PMR symptoms):

  • Increase glucocorticoid dose to last effective dose or 5-15 mg above 1

Monitoring

• Regular follow-up every 1-3 months during first year, then every 3-6 months 1
• Monitor:
  • Clinical symptoms and vascular examination
  • ESR and CRP (note: may be normal during relapse, especially with tocilizumab) 6
  • Periodic vascular imaging, especially for Takayasu arteritis 1
  • For patients on tocilizumab: CBC and liver function tests before each dose 3

Additional Considerations

• Low-dose aspirin (75-150 mg/day) for all GCA patients to reduce risk of ischemic complications 1
• Bone protection therapy for all patients on long-term glucocorticoids
• Pneumocystis jirovecii pneumonia prophylaxis for patients on multiple immunosuppressants 1

Special Situations

Vascular Complications

• Elective endovascular interventions or reconstructive surgery should be performed during stable remission 1
• For critical vascular ischemia or dissection, urgent vascular surgery consultation is required
• Collaborative decision-making between vascular surgeon and rheumatologist is essential 7

Refractory Disease

• Consider referral to centers with vasculitis expertise
• Alternative biologics may be considered:
  • For Takayasu arteritis: TNF inhibitors have shown efficacy in observational studies 4
  • For both GCA and Takayasu: Tocilizumab if not already tried 5

Pitfalls and Caveats

• Do not delay glucocorticoid treatment while awaiting biopsy results in suspected GCA 1
• Normal inflammatory markers do not rule out active disease; clinical assessment and imaging are crucial 1, 6
• Isolated elevation of inflammatory markers without symptoms should not automatically prompt treatment escalation; rule out infections first 1
• Tocilizumab suppresses inflammatory markers, making monitoring more challenging; clinical assessment becomes more important 6
• Vascular imaging may show persistent vessel wall changes even in clinical remission; interpret in clinical context 1