Giant Cell Arteritis

Giant cell arteritis is a vasculitis of the vessel wall, not the joint

In genetically and immunologically susceptible older adults, T cells and macrophages infiltrate the wall of medium and large arteries (classically the cranial branches of the external carotid), forming granulomas containing multinucleate giant cells. This inflammatory infiltrate causes intimal hyperplasia, thickening the vessel wall from the inside and progressively narrowing the lumen. The disease is therefore a problem of blood flow through inflamed arteries, and every clinical feature follows from which artery is narrowed and how much flow it still carries.