By Dr. Liji Thomas, MD Reviewed by Dr. Jennifer Logan, MD, MPH Giant cell arteritis (GCA), along with polymyalgia rheumatica (PMR), are autoimmune disorders involving the medium and large arteries which have muscular walls and vasa vasorum in their adventitial coats. What is GCA? GCA is one form of vascular inflammatory disorder that affects the large aortic branches, especially those of the carotid...