Acute Myocarditis Caused by Francisella tularensis: a Case Report

Abstract

Myocarditis is an inflammatory disease of the myocardium with either focal or diffuse involvement and usually gives rise to chest pain, dyspnea, palpitations, and fatigue. In severe cases, arrythmias, syncope, and cardiogenic shock may occur. Acute myocarditis is most commonly caused by a variety of viruses with cardiotropic properties. Rare causes of myocarditis include bacterial infections. We, herein, describe a case of acute myocarditis caused by the intracellular bacterium Francisella tularensis. A young and previously healthy male in Northern Sweden was referred to the emergency department due to intense upper-chest pain and dyspnea. ECG exhibited minimal ST-segment elevations and laboratory parameters revealed pathological levels of high-sensitivity cardiac troponin and C-reactive protein. Radiological imaging showed increased metabolism in enlarged lymph nodes in the chest and signs that could be compatible with increased metabolism in the left ventricular of the heart. The combination of acute myocarditis and enlarged lymph nodes was believed to be caused by the intracellular bacterium Francisella tularensis, endemic in the Northern Sweden, and was verified with positive serology. The patient showed full recovery after antimicrobial treatment. As this is the fifth published case of myocarditis associated with Francisella tularensis, we suggest considering tularemia in acute myocarditis in tularemia-endemic area.