Predictors of acute myocarditis in complicated scrub typhus: an endemic province in the Republic of Korea

Abstract

Background/AimsScrub typhus is known as a self-limited infectious disease. Cardiac complication is uncommon and usually not life-threatening. Until now, few cases of fulminant myocarditis by scrub typhus have been reported. So, we investigated incidence and predictors of acute myocarditis in severe scrub typhus.MethodsWe retrospectively reviewed 89 patients among 91 scrub typhus confirmed patients who examined an echocardiogram and cardiac biomarkers from 2005 to 2015 in the intensive care unit at our hospital. We excluded two patients who didn’t have electrocardiography. Patients were divided into two groups and compared between scrub typhus with (n = 13) and without (n = 76) acute myocarditis. ResultsAge, sex, and underlying diseases were similar between the groups. The existence of eschar and duration of general ache and fever were similar between the groups. However, patients with acute myocarditis had more elevated total bilirubin, high incidence of ST elevations and paroxysmal atrial fibrillation (PAF) than those without acute myocarditis. Receiver operating characteristic analysis showed that the PAF was a predictor of myocarditis with a sensitivity of 70% and specificity of 84%. Predictive power of combination of ST-segment elevation and PAF was significantly associated with myocarditis in the multivariate analysis (odds ratio, 1.57; 95% confidence interval [CI], 1.21 to 11.7; p = 0.041) and area under the curve was 0.947 (95% CI, 0.878 to 0.983; p < 0.001).ConclusionsAcute myocarditis with scrub typhus may be more common than previously reported. Patients with high bilirubin and PAF are at increased risk of acute myocarditis with scrub typhus. These patients warrant closer follow-up and echocardiogram would be needed.

New‐onset atrial fibrillation predicting for complicating cardiac adverse outcome in scrub typhus infection

“…In particular, new‐onset AF was significantly associated with concurrent AHF or IHD during treatment for scrub typhus infection. Unlike the adverse cardiac complications occurring as a result of common infections, evidence to date has been unclear concerning an association between scrub typhus infection and adverse cardiac outcomes . The present study is the first to demonstrate that new‐onset AF was significantly associated with 3‐month mortality and adverse cardiac complications in scrub typhus infection.…”

“…The present study also demonstrates that AHF concurrent with new‐onset AF could develop within only a few days of the index diagnosis of scrub typhus infection (Figure A). In addition, new‐onset AF was also associated with a greater risk for developing IHD in the critically‐ill status including complicating scrub typhus infection . Coronary vasculitis also might induce direct endothelial dysfunction and vascular injury causing atherosclerotic plaque growth or rupture during the pathogenesis of IHD .…”

“…Coronary vasculitis also might induce direct endothelial dysfunction and vascular injury causing atherosclerotic plaque growth or rupture during the pathogenesis of IHD . In particular, ECG or rhythm surveillance for cardiac complications could be a necessary monitoring of scrub typhus infection because of the risk of developing atrial or ventricular arrhythmia and changes in the ST segment of ECG as a result of active inflammation in the myocardium . Available ECG‐based new‐onset AF or ST segment change could be more readily evaluated than time and cost‐consuming echocardiogram‐based AHF or angiogram‐based IHD under the care of non‐cardiologic department.…”

“…In particular, new‐onset atrial fibrillation (AF) has been reported as a poor prognostic factor in common infectious disorders, which points to the need for investigating the association between scrub typhus infection and subsequent adverse cardiac events. New‐onset AF, acute heart failure (AHF), and ischemic heart disease (IHD) have been recognized as the major cardiac manifestations of public health adverse outcomes and the primary end points of infection‐induced cardiovascular outcomes . Therefore, we investigated whether new‐onset AF was significantly associated with 3‐month mortality and concurrent AHF and IHD in a nationwide cohort of scrub typhus infection.…”

“…4 However, with regards to scrub typhus infection complications, [5][6][7] the overall mortality rate has been reported to range from overall 16% to 30%, which might be attributed to cardiovascular complications. 8,9 In particular, new-onset atrial fibrillation (AF) has been reported as a poor prognostic factor in common infectious disorders, 10,11 which points to the need for investigating the association between scrub typhus infection and subsequent adverse cardiac events. New-onset AF, acute heart failure (AHF), and ischemic heart disease (IHD) have been recognized as the major cardiac manifestations of public health adverse outcomes and the primary end points of infection-induced cardiovascular outcomes.…”