LAUSR

External iliac artery endofibrosis (EIAE), also known as ‘cyclist’s iliac syndrome’, is an uncommon condition typically affecting young high-endurance athletes. Though EIAE was first described in the 1980s as a cause of lower leg pain in professional cyclists, it is still largely misdiagnosed.1 Moreover, arriving at the correct diagnosis can be difficult since vascular disease is unexpected in young healthy athletes. Arteries are the blood vessels that carry oxygenated blood to the organs and tissues of the body. The external iliac arteries are the main blood supply to the muscles in the legs. EIAE leads to restriction of blood flow that is not related to atherosclerotic plaque (calcification from cholesterol plaque or fatty deposits). The vessel blockage (stenosis) in EIAE can be caused by endofibrosis – a thickening of the intima, the inner layer of the vessel wall – or by kinking of the artery. In either scenario, the blood flow to the leg is reduced, which decreases oxygen delivery to the muscles and causes symptoms. EIAE has been mostly reported in cyclists, but cases have been reported in other endurance athletes including triathletes, runners, cross-country skiers, rowers, and rugby players.2