Background: Myocarditis frequently occurs in the acute phase of Kawasaki syndrome (KS), and a few severe cases have been reported. Four cases of myocarditis in KS required additional catecholamine treatment because of severe left ventricular dysfunction (LVD).
Case reports: Three cases were relatively older children and 2 cases were complicated with encephalopathy. All 4 developed coronary artery abnormalities during convalescence. There was 1 case of LVD because of prolonged severe inflammation prior to administration of intravenous immunoglobulin (IVIG). The remaining 3 patients had normal values for ejection fraction before the administration of IVIG but decreased values (42-51%) and increased C-reactive protein levels after IVIG administration. These cases demonstrate an association between myocarditis in KS and severe or worsened inflammation.
Conclusions: Even with prior normal echocardiography, careful observation of cardiac function may be necessary for patients with KS, especially older children, when inflammation deteriorates after administration of IVIG.