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

Treatment of Giant Cell Arteritis

For newly diagnosed GCA, initiate high-dose oral glucocorticoids (40-60 mg/day prednisone) combined with tocilizumab 162 mg subcutaneously weekly to achieve rapid disease control while minimizing long-term steroid toxicity. 1, 2, 3

Initial Glucocorticoid Therapy

Standard Presentation (No Vision Threat)

• Start high-dose oral prednisone at 40-60 mg/day as a single daily dose rather than IV pulse steroids or moderate-dose regimens 1, 3
• Daily dosing is superior to alternate-day schedules for achieving remission 1
• High-dose oral therapy achieves rapid disease control within days, preventing irreversible ischemic complications 3, 4

Vision-Threatening Disease

• For patients with threatened vision loss, amaurosis fugax, or acute visual symptoms, initiate IV pulse methylprednisolone (15 mg/kg/day for 3 days) followed by high-dose oral prednisone 1, 5
• IV pulse therapy in this high-risk population allows more rapid oral steroid tapering and higher sustained remission rates compared to oral therapy alone 5
• However, IV steroids do not reverse established vision loss—only 4% of patients with visual loss show improvement regardless of route 4

Glucocorticoid-Sparing Agents: First-Line Tocilizumab

Add tocilizumab 162 mg subcutaneously weekly (or 8 mg/kg IV monthly) at diagnosis in combination with glucocorticoids rather than using glucocorticoids alone 1, 2, 6

Rationale for Tocilizumab

• Tocilizumab is FDA-approved specifically for GCA and demonstrates significant glucocorticoid-sparing effects with reduced relapse rates 6, 7
• The 2021 ACR/Vasculitis Foundation guidelines conditionally recommend tocilizumab over glucocorticoid monotherapy for all newly diagnosed patients 1
• This allows rapid prednisone tapering while maintaining disease control, reducing cumulative steroid exposure and toxicity 2, 3

Alternative: Methotrexate

• Methotrexate (15-25 mg weekly) can be used instead of tocilizumab in patients with contraindications to tocilizumab (active diverticulitis with recent perforation, recurrent severe infections, cost barriers) 1, 2
• Methotrexate has modest efficacy compared to tocilizumab but provides some glucocorticoid-sparing benefit 8, 7

Third-Line: Abatacept

• Abatacept is mentioned only as a third-line option when tocilizumab and methotrexate fail or are contraindicated 1

Special Clinical Scenarios

Large Vessel Involvement

• For extracranial large vessel GCA (limb claudication, imaging-confirmed aortitis), combine oral glucocorticoids with a non-glucocorticoid immunosuppressive agent (preferably tocilizumab) from the outset 1
• Obtain baseline noninvasive vascular imaging (CT/MR angiography of neck/chest/abdomen/pelvis) to detect large vessel involvement 1

Critical Vascular Stenosis

• Add aspirin for patients with critical or flow-limiting stenosis of vertebral or carotid arteries to reduce thrombotic risk 1, 3

Glucocorticoid Tapering Strategy

• Maintain initial high-dose prednisone (40-60 mg/day) until ESR and CRP normalize and stabilize at low levels, typically 2-4 weeks 3, 4
• Begin gradual tapering only after inflammatory markers stabilize, guided by ESR/CRP levels rather than symptoms alone 4
• Target prednisone dose of 10-15 mg/day by 3 months 3
• The optimal tapering schedule varies dramatically between individuals—median time to reach lowest maintenance dose is approximately 48 months, with median maintenance dose of 7 mg/day 4
• Most patients require 1-2 years of therapy, though some need low-dose glucocorticoids for several years 3, 8

Management of Relapse

Relapse on Moderate-to-High Dose Glucocorticoids

• Add a non-glucocorticoid immunosuppressive agent (tocilizumab preferred) rather than simply increasing glucocorticoid dose 1

Relapse with Cranial Ischemic Symptoms

• Add tocilizumab (preferred over methotrexate) AND increase glucocorticoid dose to prevent irreversible complications 1
• This dual approach is superior to glucocorticoid escalation alone for high-risk relapses 1

Monitoring and Long-Term Management

• All patients in apparent remission require long-term clinical monitoring to detect relapses early 1
• Monitor with clinical symptoms, ESR, and CRP at regular intervals 3
• Isolated elevation of inflammatory markers without symptoms warrants observation and monitoring without immediate treatment escalation 1
• Provide bone protection therapy (calcium, vitamin D, bisphosphonates) to all patients on long-term glucocorticoids 3

Critical Pitfalls to Avoid

• Never delay treatment while awaiting temporal artery biopsy—GCA is a medical emergency with imminent risk of permanent vision loss 3, 4
• Do not use IV pulse steroids routinely in patients without vision-threatening disease, as this increases infection risk without clear benefit in standard cases 1, 9
• Do not taper glucocorticoids based on symptom resolution alone—use ESR and CRP levels to guide tapering, as up to 60% of patients relapse during tapering 3, 4
• Avoid inappropriately withholding tocilizumab in all patients with any history of diverticulitis—only active/recent perforation is a true contraindication 2
• The risk of permanent vision loss, stroke, or aortic complications from undertreated GCA far exceeds theoretical perforation risk in patients with remote diverticulitis history 2