**4. Pathogenesis**

Initially, activated inflammatory cells, particularly monocytes, macrophages, T-cells, and subsequently platelets, adhere to the endothelial cells that line medium-size elastic arteries. Other mediators contribute to destruction of the extra-cellular matrix, leading to vessel dilatation, and subsequent smooth muscle proliferation in the media contributes to later pathology. There is destruction of the intimal layer of the affected artery with inflammatory infiltrate during the acute phase, and histologic findings of myocarditis and fibrosis are found in virtually all cases with Kawasaki disease (Yutani et al., 1981).
