What is the initial treatment for Giant Cell Arteritis (GCA)?

Initial Treatment for Giant Cell Arteritis

Start high-dose oral glucocorticoids (40-60 mg/day prednisone or equivalent) immediately upon clinical suspicion of GCA, without waiting for biopsy confirmation. 1, 2

Immediate Treatment Based on Clinical Presentation

For GCA WITHOUT Threatened Vision Loss

• Initiate high-dose oral prednisone 40-60 mg/day (or 1 mg/kg/day, maximum 60 mg/day) as a single daily dose 1, 2
• Daily dosing is superior to alternate-day schedules for achieving remission 1
• Begin treatment immediately—do not delay for temporal artery biopsy, which can be performed within 2 weeks of starting therapy without compromising diagnostic accuracy 3, 2

For GCA WITH Threatened Vision Loss or Acute Visual Symptoms

• Administer IV pulse methylprednisolone 500-1000 mg/day (or 0.25-1 g/day) for 3 consecutive days, followed immediately by high-dose oral prednisone 40-60 mg/day 1, 2
• This represents a neuro-ophthalmic emergency requiring immediate intervention 4
• The EULAR guidelines specifically recommend IV methylprednisolone for acute visual loss or amaurosis fugax, though evidence quality is limited 1
• Do not delay oral glucocorticoid initiation while arranging IV therapy 1

First-Line Adjunctive Therapy

Tocilizumab as Glucocorticoid-Sparing Agent

• Add tocilizumab 162 mg subcutaneously weekly to oral glucocorticoids as first-line therapy, particularly for patients at high risk of steroid-related complications 1, 2
• The 2021 ACR/Vasculitis Foundation guidelines conditionally recommend tocilizumab with oral glucocorticoids over glucocorticoids alone based on high-quality evidence demonstrating significant glucocorticoid-sparing effects 1
• Tocilizumab reduces relapse rates and minimizes cumulative steroid exposure 2
• Consider methotrexate as an alternative if tocilizumab is contraindicated due to recurrent infections, gastrointestinal perforation history, diverticulitis, or cost concerns 1, 2

Aspirin Therapy

• Add low-dose aspirin (75-150 mg/day) for all patients unless contraindicated 2
• Aspirin is particularly important for patients with critical or flow-limiting involvement of vertebral or carotid arteries 1

Special Considerations for Large Vessel Involvement

• For patients with active extracranial large vessel involvement, combine oral glucocorticoids with a non-glucocorticoid immunosuppressive agent (tocilizumab or methotrexate) rather than glucocorticoids alone 1
• Obtain noninvasive vascular imaging (ultrasound, CT, PET-CT, or MRI) at diagnosis to evaluate large vessel involvement 1, 3

Supportive Care from Day One

• Initiate bone protection with calcium and vitamin D supplementation immediately 3, 4
• Consider proton pump inhibitor for peptic ulcer prophylaxis 4
• Monitor blood pressure closely, as high-dose glucocorticoids may worsen hypertension 3

Critical Pitfalls to Avoid

• Never delay treatment while awaiting temporal artery biopsy results—vision loss can be permanent and irreversible 2, 4
• Do not use moderate-dose glucocorticoids (e.g., 20-30 mg/day) as initial therapy; evidence supporting lower doses is of insufficient quality 1
• Avoid rapid steroid withdrawal, which leads to disease exacerbation 2
• Do not use statins specifically for GCA treatment (though they may be indicated for cardiovascular risk reduction) 1
• Do not use infliximab, as it is associated with recurrent ocular symptoms and disease activity 2

Evidence Quality Considerations

The recommendation for high-dose oral glucocorticoids is based on decades of clinical experience, though the evidence level is rated as "very low to low" by GRADE methodology due to lack of placebo-controlled trials (which would be unethical given the risk of permanent vision loss) 1. The 2021 ACR/Vasculitis Foundation guidelines represent the most recent high-quality guidance, superseding earlier recommendations 1. The addition of tocilizumab is supported by high-quality randomized controlled trial evidence from 2017 1.