Influenza B-Induced Fulminant Myocarditis Leading to Cardiogenic Shock
Introduction: A significant association between myocarditis and influenza A virus infection was seen in the 1918 influenza pandemic. However, since then the link between influenza B virus and fulminant myocarditis or cardiogenic shock requiring mechanical circulatory support has been rarely reported.
Case Presentation: 60 year old man with undiagnosed hypertension, 40 pack year smoker and strong family history of coronary artery disease presented with myalgias and nasal congestion for the past three days then started having exertional dyspnea and resting chest pain on the morning of his presentation. His initial examination was unremarkable except for BP of 180/100mmHg. EKG showed 1mm inferior ST depressions with a troponin of 0.60ng/ml peaking to 14.40ng/ml. CT angiogram of the chest was negative for pulmonary embolism or aortic dissection. An urgent transthoracic echocardiogram showed normal wall motion and ejection fraction (EF) without pericardial effusion. His nasal swab came positive for influenza B with negative blood, urine and sputum cultures. He was started on aspirin, clopidogrel, atorvastatin, carvediolol in addition to heparin and nitroglycerin infusions. However, the next morning his BP started to drop despite turning off nitroglycerin infusion and became hypoxic for which he was intubated and transferred to intensive care unit for vasopressors. Due to cold extremities and worsening hemodynamics a repeat echocardiogram was done that showed EF of 25% and global hypokinesis. Therefore, he was taken for combined heart catheterization that showed only mild luminal irregularities in the coronaries with elevated pulmonary capillary wedge pressures of 24mmHg and severely reduced cardiac index of 1.3L/min/m2. Decision was made to place Impella CP and do VA ECMO cannulation to maintain circulatory support. He continued to require norepinephrine and dopamine infusions for hemodynamic support so he was transferred to a heart transplant center where his hemodynamics started improving leading to successful VA ECMO decannulation five days later and eventual initiation of metoprolol succinate and lisinopril on discharge with an EF improvement to 40%.
Conclusion: Patients with influenza B infection presenting with cardiac symptoms should be carefully evaluated and closely monitored as it can be complicated by fulminant myocarditis within a day leading to cardiogenic shock. Usually myocardial recovery does occur however intensive mechanical circulatory support with Impella and VA ECMO might be required in the interim.
Published In/Presented At
Sabzwari, S. R. A., Mann, K. Ayele, H. Kimber, J. Burke, J. (2018, Nov). Influenza B-Induced Fulminant Myocarditis Leading to Cardiogenic Shock. Circulation, 138 Suppl_1.
Department of Medicine, Department of Medicine Faculty, Department of Medicine Fellows and Residents, Cardiology Division