Coronary Artery Vasculitis

Coronary artery vasculitis is an inflammatory injury of the coronary vessel wall rather than a single disease. In a young child, the leading diagnosis is Kawasaki disease (KD), an acute, self-limited medium-vessel vasculitis with a particular affinity for the coronary arteries. In adults, systemic vasculitides such as polyarteritis nodosa (PAN) or Takayasu arteritis can affect the coronary circulation, although their vascular patterns differ. KD inflammation can extend through the full thickness of the arterial wall. Enzymatic destruction of the elastic tissue and media weakens the vessel, producing dilation or an aneurysm. Aneurysmal segments disturb blood flow and promote thrombosis; later healing may produce fibrosis and stenosis. This is why a child can move from fever and inflammation to myocardial ischemia even after the systemic illness seems to be settling. Without treatment, approximately 25% of children with KD develop coronary dilation or aneurysm. A single 2 g/kg infusion of intravenous immune globulin (IVIG) given promptly reduces that risk to under 5%. The clinical priority is therefore not simply to lower the fever. It is to identify the inflammatory illness before coronary...