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

Treatment of Giant Cell Arteritis (GCA)

Immediate high-dose glucocorticoids must be initiated urgently upon clinical suspicion of GCA, without waiting for diagnostic confirmation, to prevent irreversible vision loss and other ischemic complications. 1, 2

Immediate Initial Treatment

Glucocorticoid Therapy

• Start high-dose oral glucocorticoids immediately at 1 mg/kg/day (maximum 60 mg/day, typically 40-60 mg/day) for patients without threatened vision loss 1, 2, 3
• Daily dosing is preferred over alternate-day schedules 2
• Treatment should begin even before temporal artery biopsy or imaging confirmation, as sight loss occurs almost exclusively before glucocorticoid initiation 1
• The risk of losing vision in the second eye is 50% if one eye is already affected without treatment 1, 2

Rationale for Urgency

GCA is a medical emergency because 15-35% of patients develop sight loss, which has devastating impact on quality of life 1, 2. Once glucocorticoids are started, the risk of visual impairment decreases dramatically 1.

Adjunctive Therapy at Diagnosis

Tocilizumab

• Consider adding tocilizumab (FDA-approved for GCA) at diagnosis in combination with glucocorticoids to reduce glucocorticoid requirements and flare rates 1, 2, 4
• Tocilizumab 162 mg subcutaneously weekly is the standard regimen 4
• This combination significantly improves outcomes compared to glucocorticoids alone 2

Antiplatelet Therapy

• Add aspirin (100 mg/day) for patients with critical or flow-limiting involvement of vertebral or carotid arteries 2
• Low-dose aspirin significantly decreases the rate of vision loss and stroke during disease course 3

Treatment Target and Monitoring Strategy

Primary Goal

• The treatment target is remission, defined as absence of clinical symptoms AND systemic inflammation 1, 2
• Treatment must also prevent tissue ischemia and vascular damage 1

Monitoring Frequency

• Monitor disease activity every 1-4 weeks until remission is achieved 1
• Once in stable remission, extend monitoring intervals to every 3-6 months 1
• Use clinical symptoms plus ESR and CRP for monitoring (though these can be nonspecific) 1, 2
• Obtain baseline noninvasive vascular imaging (ultrasound or PET/CT) to evaluate large vessel involvement 2

Critical caveat: Elevated inflammatory markers alone without clinical symptoms do not warrant treatment escalation, but should prompt more frequent clinical and radiographic assessments 1.

Glucocorticoid Tapering Protocol

• Maintain initial high-dose glucocorticoids for approximately one month 2
• Taper gradually based on clinical symptoms and normalization of inflammatory markers 2
• Target glucocorticoid dose at 3 months: 10-15 mg/day 2
• Aim for minimal effective dose to maintain remission 1
• Drug-free remission may be achieved in a proportion of patients 1

Important warning: Up to 60% of patients experience one or more relapses during glucocorticoid tapering 1, 2. Patients must be educated that premature discontinuation risks not only symptom return but also ischemic complications 1.

Management of Disease Relapse

Relapse with Cranial Ischemic Symptoms

• Add tocilizumab AND increase glucocorticoid dose (preferred over methotrexate) 1, 2
• Tocilizumab demonstrates superior glucocorticoid-sparing effect compared to methotrexate 1
• Methotrexate can be considered only if tocilizumab is unavailable or not tolerated 1

Relapse with Polymyalgia Rheumatica Symptoms Only

• Increasing glucocorticoid dose alone may be sufficient for PMR symptoms without cranial features 1

Relapse on Moderate-to-High Dose Glucocorticoids

• Add a non-glucocorticoid immunosuppressive agent (tocilizumab or methotrexate) rather than further increasing glucocorticoids 1, 2

Special Clinical Situations

Limb/Organ Ischemia

• Escalate immunosuppressive therapy first rather than immediate surgical intervention 1
• Patients can develop collateral blood vessels to improve distal blood flow 1
• Immediate surgical intervention is warranted only for: aortic aneurysms at high risk for rupture or impending/progressive tissue or organ infarction 1

GCA/PMR Overlap

• Monitor more carefully as PMR often signals GCA relapse 1, 2
• Patients with recurrent PMR relapses or inability to taper glucocorticoids may have underlying GCA that was initially masked 1

Multidisciplinary Management Requirements

GCA requires collaboration with multiple specialists because it affects different vascular territories 1:

• Ophthalmologists (for vision complications)
• Neurologists (for stroke risk)
• Vascular surgeons (for aneurysms, stenoses, limb ischemia)
• Plastic surgeons (for scalp/tongue necrosis)

Fast-track GCA clinics have proven effective in reducing symptom-to-therapy lag and improving outcomes 1.

Essential Supportive Care

• Provide bone protection therapy to all patients on long-term glucocorticoids 2
• Long-term clinical monitoring is mandatory even in apparent remission, given the catastrophic potential outcomes without surveillance 1