Kawasaki syndrome.

Kawasaki syndrome is a leading cause of pediatric acquired heart disease in the United States. Coronary artery aneurysms or ectasia develop in approximately 15 to 25 per cent of affected children; treatment with intravenous gamma globulin in the acute phase reduces this risk three- to five-fold. Angiographic resolution occurs in approximately one half of aneurysmal arterial segments, but these show persistent histologic and functional abnormalities. The remainder may continue to be aneurysmal, often with development of progressive stenosis or occlusion. Myocarditis is a universal feature of acute Kawasaki syndrome, but the occurrence of late abnormalities of myocardial function among children without coronary artery disease is controversial. Aortic and mitral regurgitation may occur in the acute illness, and late-onset valvar regurgitation has been reported as a rare complication. Continued long-term surveillance in patients with and without detected coronary abnormalities is necessary to determine the nature history of Kawasaki syndrome with respect to coronary artery status, myocardial function, and valvar regurgitation.