Also called Vasculitis.  An inflammation of blood vessels which causes changes in the walls of the blood vessels such as thickening,  weakening, narrowing, or scarring.  Can prevent proper blood flow.  May close off flow completely so that blood cannot get through at all (occlusion), or stretch and weaken causing bulging (aneurysm) or burst (rupture).  Symptoms include fever, fatigue, weight loss, muscle and joint pain, and loss of appetite.