Rare pediatric case of two episodes of fulminant myocarditis and cardiac dysfunction after viral infection.

Unlabelled: Myocarditis presents with a broad spectrum of clinical severity, ranging from subclinical illness to sudden death. Children with fulminant myocarditis often require inotropic or mechanical circulatory support; however, recurrent acute myocarditis is extremely rare. There is limited evidence to guide the management of recurrent acute myocarditis because the relevant literature is sparse. Here, we present a rare pediatric case of recurrent acute myocarditis. This patient experienced two episodes of fulminant myocarditis and two episodes of suspected myocarditis over an eight-year period; each episode fully resolved with preserved cardiac function. Three episodes were associated with influenza virus infection. During each episode, the electrocardiography, echocardiogram, and laboratory findings improved. Autoimmune and chronic myocarditis were not suspected because of the rapid onset of myocarditis associated with viral infection. Genetic testing by next-generation sequencing was performed; however, no underlying genetic illnesses were identified. Human leukocyte antigen genotyping was performed, and the results determined the genotype to be HLA-DQB1*0302/0303, which reports indicate might be involved in the development of myocarditis in mice or humans. The combination of these genotypes in myocardial cells may be associated with susceptibility to influenza infection or acute myocarditis.

Learning Objective: There is little evidence regarding susceptibility to myocarditis. We present a pediatric patient who experienced two episodes of fulminant myocarditis and two episodes of suspected myocarditis associated with influenza infection and a specific human leukocyte antigen genotype. This case highlights the importance of understanding myocarditis susceptibility.