Giant Cell Arteritis Diagnosis and Treatment

Diagnosis

The American College of Rheumatology suggests that a 91-year-old patient with severe headache, markedly elevated ESR, and hypoxia is likely to have giant cell arteritis (GCA), and high-dose glucocorticoid therapy should be initiated immediately without waiting for temporal artery biopsy results 1, 2
ESR >100 mm/h has 92.2% specificity for GCA with a positive likelihood ratio of 3.11, according to the American College of Rheumatology 3
Negative head CT does not exclude GCA, as CT is used to rule out subarachnoid hemorrhage or mass lesions, not to diagnose vasculitis, as stated by the American Heart Association 4, 5, 6
Hypoxia suggests large vessel involvement, and GCA can affect the aorta and its branches, potentially causing pulmonary complications through thoracic aortic involvement, according to the American College of Cardiology 1, 2

The American College of Rheumatology recommends starting prednisone 60 mg daily (or equivalent IV methylprednisolone if unable to take oral) immediately, without waiting for temporal artery biopsy results 1, 2
Temporal artery biopsy should be performed but must not delay treatment, and it can be done within 1-2 weeks of starting steroids, as suggested by the American College of Rheumatology 1, 2
The American Heart Association suggests adding aspirin 75-150 mg daily to reduce the risk of cardiovascular and cerebrovascular events, and considering gastroduodenal protection (proton pump inhibitor) when starting aspirin 1, 2

The American College of Rheumatology recommends monitoring ESR and CRP to assess treatment response, though clinical improvement is more important, and relapse is usually associated with rising ESR 1, 2
Consider adjunctive immunosuppression (methotrexate, azathioprine) to facilitate steroid reduction, as suggested by the American College of Rheumatology 1, 2