About a month after coming off of my prednisone taper for PMR, I started to have some jaw discomfort and occasional mild headaches. I did a bit of research and discovered those could be symptoms of GCA. I quickly requested an appointment with a rheumatologist and he immediately scheduled me for a temporal biopsy. The biopsy confirmed the diagnosis of GCA. I then started another 10 month prednisone taper (beginning at 60mg daily) and had my first Actemra infusion. I have had 12 infusions and will continue those for at least another year before reassessing.

Regarding diagnosing GCA, read page 4 of this document:
https://www.vasculitisfoundation.org/wp-content/uploads/2021/07/2021-ACR-VF-Guideline-for-Management-of-Giant-Cell-Arteritis-and-Takayasu-Artheritis.pdf