Background: An association between influenza A viruses and myocarditis was noted during the 1918 influenza pandemic. Since then, the link between the influenza B virus and fulminant myocarditis or cardiogenic shock has been rarely reported.
Case presentation: In February 2013, a 50 year-old-woman without known heart disease presented in profound cardiogenic shock with a left ventricular ejection fraction of 10%. Her presentation was preceded by six days of fever, chills, myalgia and fatigue. She had a junctional tachycardia, a troponin I of 12.6 ng/ml and her coronary angiography demonstrated normal coronary arteries. Percutaneous extracorporeal membrane oxygenation was required. An endotracheal aspirate at admission was positive for influenza B. All other respiratory, blood and urine cultures were negative. On day 7, a repeat echocardiography demonstrated significant recovery of left ventricular function with an ejection fraction of 50%. She was later discharged home in good condition.
Conclusions: Influenza B infection can be complicated by fulminant cardiomyopathy leading to cardiogenic shock in adults without preexisting cardiac disease.