What is the recommended workup and treatment for suspected giant cell arteritis and vasculitis?

Workup and Treatment for Giant Cell Arteritis and Vasculitis

The recommended workup for suspected giant cell arteritis includes temporal artery biopsy as the gold standard diagnostic test, with high-dose glucocorticoids initiated immediately upon suspicion, especially with visual symptoms, and consideration of tocilizumab as a first-line adjunctive agent. 1

Diagnostic Workup for Giant Cell Arteritis

Clinical Presentation to Consider

• Headache, scalp tenderness (affects up to two-thirds of patients)
• Jaw claudication (affects approximately 50% of patients)
• Visual symptoms including amaurosis fugax, diplopia, blurry vision (up to 20% of patients)
• Constitutional symptoms: weight loss, night sweats, malaise, fever (about 50% of patients)
• Polymyalgia rheumatica symptoms (affects approximately 50% of patients)
• Fatigue, reduced pulsation, and bruits particularly in the axilla

Laboratory Tests

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) - elevated in >95% of cases
• Complete blood count - anemia present with sensitivity of 87.4%

Imaging and Biopsy

1. Temporal Artery Biopsy (Gold Standard) 2, 1

   • Conditionally recommended over ultrasound or MRI for establishing diagnosis
   • Long-segment specimen (>1 cm) over short-segment (<1 cm)
   • Should be obtained within 2 weeks of starting glucocorticoids
   • Pathology shows arterial wall thickening, narrowed lumen, inflammatory cell infiltration, and multinucleated giant cells in the media

2. Noninvasive Vascular Imaging 2

   • Recommended when temporal artery biopsy is negative
   • Recommended for newly diagnosed GCA to evaluate large vessel involvement
   • Options include:
     • Ultrasound: "halo" sign has 77% sensitivity and 96% specificity
     • MRI of cranial arteries (alternative when ultrasound unavailable)

Treatment Algorithm for Giant Cell Arteritis

Initial Treatment

1. For patients with visual symptoms (emergency treatment) 1, 3

   • IV methylprednisolone 500-1000 mg/day for 3 days
   • Then transition to oral prednisone 40-60 mg/day

2. For patients without visual symptoms 2, 1, 3

   • Oral prednisone 40-60 mg/day (1 mg/kg)
   • Daily dosing is conditionally recommended over alternate-day schedule 2

3. Adjunctive Therapy 2, 1, 4

   • Tocilizumab (FDA approved for GCA): 162 mg subcutaneously weekly

     • Conditionally recommended with oral glucocorticoids over oral glucocorticoids alone
     • Reduces glucocorticoid requirements and relapse rates

   • Aspirin 75-150 mg/day for patients with critical or flow-limiting involvement of vertebral or carotid arteries

Maintenance and Monitoring

• Treatment typically requires 1-2 years with gradual tapering
• Taper prednisone by approximately 10 mg per month based on clinical response
• Monitor:
  • Symptoms
  • Physical examination
  • Inflammatory markers (ESR and CRP)
  • Glucocorticoid-related adverse effects

Management of Relapse 2, 1

• For relapse with symptoms of cranial ischemia:
  • Add tocilizumab (preferred) and increase glucocorticoid dose
  • Alternative: add methotrexate and increase glucocorticoid dose
• For relapse without cranial ischemia:
  • Add non-glucocorticoid immunosuppressive drug

Special Considerations

• For patients with GCA undergoing vascular surgical intervention with active disease, high-dose glucocorticoids are conditionally recommended during the periprocedural period 2
• For patients with isolated increases in inflammatory markers without clinical symptoms, clinical observation and monitoring without escalation of immunosuppressive therapy is conditionally recommended 2

Pitfalls and Caveats

• Delayed treatment: Vision loss occurs in 15-35% of untreated GCA patients and is often permanent; treatment should not be delayed while awaiting biopsy results
• Inadequate initial dosing: Underdosing glucocorticoids initially may lead to irreversible complications
• Tapering too quickly: Rapid tapering increases risk of relapse
• Relying solely on ESR/CRP: While useful, inflammatory markers may not always correlate with disease activity
• Missing large vessel involvement: Always consider noninvasive vascular imaging even with negative temporal artery biopsy

Takayasu Arteritis Workup and Treatment

For Takayasu arteritis, the American College of Rheumatology conditionally recommends:

• High-dose oral glucocorticoids over IV pulse glucocorticoids for initial treatment 2
• Adding a non-glucocorticoid immunosuppressive agent plus glucocorticoids over glucocorticoids alone 2
• Medical management over surgical intervention for renovascular hypertension and cranial/cervical vessel stenosis 2

The diagnostic and treatment approach to other vasculitides should be tailored to the specific type, but generally follows similar principles of early diagnosis, prompt immunosuppression, and monitoring for disease activity and treatment complications.