Fulminant Myocarditis Associated with Pandemic H1N1 Influenza A Virus

Fulminant myocarditis associated with influenza A virus is exceedingly rare, with only a few cases reported in the literature. We describe a previously healthy 10-year-old boy, with a three-day history of flu-like symptoms without antiviral treatment. He was hospitalized with dehydration and hypothermia in the context of persistent vomiting, when he suddenly developed heart failure secondary to fulminant myocarditis. Despite aggressive management, including circulatory support and cardiopulmonary resuscitation measures, the patient died of cardiogenic shock. The postmortem histopathology was compatible with a multisystem viral infection with myocarditis and pulmonary involvement, and H1N1v polymerase chain reaction was positive. The prevalence of influenza-associated fulminant myocarditis remains unknown. Findings reported in the literature raise the possibility that the novel H1N1 influenza A virus is more commonly associated with a severe form of myocarditis than previously encountered influenza strains.