Myocarditis secondary to smallpox vaccination

Abstract

The development of vaccines ushered in the most profound advancement in 20th century medicine, and have widely been regarded as the one of the most important scientific discovery in the history of mankind. However, vaccines are not without risk; reactions can range from injection site reactions to life-threatening anaphylaxis. Among the more serious vaccine-related sequela is myocarditis. Although myocarditis has been reported following many different vaccines, the smallpox vaccine has the strongest association. We report a case of a 36-year-old active duty service member presenting with progressive dyspnoea, substernal chest pain and lower extremity swelling 5 weeks after receiving the vaccinia vaccination. The aetiology of his acute decompensated heart failure was determined to be from myocarditis. Although the majority of cases of myocarditis resolve completely, some patients develop chronic heart failure and even death. Vaccine-associated myocarditis should always be on the differential for patients that exhibit cardiopulmonary symptoms after recent vaccinations.

Keywords: heart failure; pericardial disease; radiology (diagnostics); vaccination/immunisation.

Figure 1

Four chamber cardiac MRI cine (A) with small pericardial effusion and left ventricular apical thrombus (red arrow). Late gadolinium enhancement short axis (B), four chamber (C) and two chamber (D) view demonstrating subendocardial enhancement (yellow arrows) in the midinferior segment and subepicardial enhancement (yellow arrows) in the basal to midanterior, basal anteroseptal and midanterolateral segment. There was no acute oedema indicating chronic process. Early gadolinium enhancement was abnormal. Two of three MRI criteria for myocarditis were met.