How do you make the decision to empirically treat for GCA when a patient is referred but cannot be immediately seen in clinic?

This is an important question because referrals for possible GCA are common scenarios when a rheumatologist may be asked to recommend a treatment before seeing the patient which are often challenging scenarior. The factors I typically rely on to rate the probability of GCA include:

- Specific symptoms - such as jaw claudication, PMR, scalp tenderness

- Highly concerning symptoms - such as visual changes

- Inflammatory markers

The presence of common symptoms (such as headache) in the setting of markedly elevated inflammatory markers without an alternative explanation, the presence of specific or concerning symptoms particularly in the setting of elevated inflammatory markers make the risk of GCA to me at least intermediate and merit empiric ...

This case is a prime example of the "art of rheumatology". A real-life scenario where medical decision-making is mostly based on personal and anecdotal experience. Recently developed algorithms such as GCAPS can help identify those patients who are more likely to have GCA, but this is an imperfect tool. And one of the great fears of rheumatologists is missing the undiagnosed GCA patient who goes on to catastrophic visual loss.

In the optimal situation, the rheumatologist has access to temporal artery ultrasonography. There are many centers that now offer "same day" testing. I have frequently relied on these results (which hopefully can be ordered and obtained quickly) along with the results of the ESR and C-RP. Unlike PMR, where a small but...

I must commend Dr. @Dr. First Last for his concise and brilliantly crafted response; I wholeheartedly agree with his approach. Ultrasound is such a critical tool in this setting since it allows you to screen the temporal arteries and its branches as well as the facial artery, carotid artery, subclavian artery and axillary arteries for a halo with a compression sign (the most sensitive indications of GCA) as well as sites of focal stenosis (less specific but helpful nonetheless); a skilled provider can assess the abdominal aorta as well. In cases when PMR is suspected but less clear, ultrasound can help in assessment for subdeltoid bursitis, long-head bicipital tenosynovitis, glenohumoral synovitis, femoroacetabular synovitis (hip joint), an...

Treatment should not be withheld pending temporal artery biopsy. Although glucocorticoids to reduce the positive rate of biopsies a nice retrospective study of 183 cases out of Sweden showed that 80% of biopsied taken 1-4 weeks after glucocorticoid treatment were still positive

Jakobsson et al., PMID 27558589