Giant Cell Arteritis Diagnosis and Management

Clinical Presentation and Diagnosis

The American College of Rheumatology suggests considering GCA even without typical temporal headache if the patient presents with limb claudication, constitutional symptoms alone, large vessel involvement, polymyalgia rheumatica symptoms, or unexplained stroke or cerebral ischemia in patients over 50 years 1, 2, 3, 4
Limb claudication has a positive likelihood ratio of 6.01 for GCA, making it the strongest predictor 3, 4
Jaw claudication has a positive likelihood ratio of 4.90 for GCA 3, 4
Temporal artery abnormalities, such as thickening, loss of pulse, or tenderness, also have positive likelihood ratios for GCA 3, 4

ESR and CRP are essential for diagnosing GCA, as they provide complementary information 3, 4, 5
An ESR >100 mm/h has a positive likelihood ratio of 3.11 for GCA, while a normal ESR (<40 mm/h) argues strongly against GCA (negative likelihood ratio 0.18) 3, 4
A normal CRP (<2.5 mg/dL) also argues strongly against GCA (negative likelihood ratio 0.38) 3, 4
Thrombocytosis >400 × 10³/μL supports GCA (positive likelihood ratio 3.75) 3, 4

The American College of Rheumatology recommends starting high-dose oral glucocorticoids (40-60 mg/day prednisone) immediately for patients with suspected GCA, even before diagnostic confirmation 1, 2, 6, 7
For patients with threatened vision loss, IV pulse glucocorticoids should be started immediately, followed by high-dose oral glucocorticoids 6, 7, 8
Tocilizumab (IL-6 receptor antibody) can be added to oral glucocorticoids to reduce cumulative glucocorticoid dose and relapse frequency 6, 7
Low-dose aspirin (100 mg daily) can be added for patients with critical or flow-limiting involvement of vertebral or carotid arteries 6, 7

The American College of Rheumatology recommends obtaining a long-segment temporal artery biopsy (>1 cm) rather than short-segment (<1 cm) to maximize diagnostic yield with minimal added morbidity 9
The American College of Rheumatology suggests performing unilateral temporal artery biopsy initially rather than bilateral biopsies 9
Temporal artery biopsy should be obtained within 2 weeks of starting glucocorticoids, as histopathologic changes are more likely to be detected within this timeframe 9
The American College of Rheumatology recommends starting high-dose glucocorticoids immediately when GCA is suspected, even before diagnostic confirmation, and not waiting for biopsy results or imaging before starting treatment 9

For patients with suspected GCA and negative temporal artery biopsy, noninvasive vascular imaging of the large vessels should be obtained to aid in diagnosis 9
Noninvasive vascular imaging should be used to evaluate large vessel involvement in patients with newly diagnosed GCA, to assess disease extent and guide management 9
Patients with GCA require long-term clinical monitoring, including history, examination, and laboratory studies, to guide glucocorticoid tapering and prevent catastrophic outcomes 10, 11, 12
Isolated elevation of inflammatory markers without clinical symptoms does not warrant escalation of immunosuppressive therapy, and instead, observation and more frequent monitoring are recommended 10, 11, 12