Circulating cardiac biomarkers and echocardiographic abnormalities in patients with scrub typhus

Abstract

Background & objectives: Cardiac injury in scrub typhus is uncommonly reported. We studied the incidence and clinical significance of cardiac involvement among seventy consecutive adult patients of scrub typhus, using circulating cardiac biomarkers, including N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), troponin T, creatine kinase-muscle/brain isoenzyme (CK-MB) and 2D-echocardiography. Methods: This was a hospital-based prospective cohort study conducted in the medical emergency of PGIMER, Chandigarh, India. Seventy consecutive patients aged 12 years and above with the diagnosis of scrub typhus were enrolled. Results: Elevations of NT pro-BNP, troponin T, and CK-MB levels were observed in 70 (100%), 51 (72.8%), and 29 (41.4%) patients, respectively. Echocardiography detected reduced ejection fraction (EF) in 30 patients (42.8%) with mild reduction (EF 45-54 %) in 20 (28.5%) and moderate reduction (EF 30-44%) in 10 (14.3%). The age showed a significant difference with EF (p-value 0.003), and the patients with moderate reduction were younger (mean age of 20.7 ± 5.6 years). Pericardial effusion was found in nine patients (12.9%). Increased circulating levels of all the three cardiac biomarkers showed statistically significant association with a systolic dysfunction on echocardiography, and elevated CK-MB level further predicted a longer duration of hospital stay (p-value 0.002). No statistically significant association was observed between cardiac biomarkers or reduced EF and mortality. Interpretation & conclusion: Cardiac injury is a common condition among patients with scrub typhus admitted in a medical emergency; however, it does not influence in-hospital mortality.

The first case report of acute myocardial infarction in young adult caused by scrub typhus

“…Cardiac injury was commonly seen in patients with O tsutsugamushi infection, presenting as NT pro-BNP, troponin T, and CK-MB levels elevated as well as ejection fraction reduced in echocardiography, and ECG abnormalities. [ 6 , 17 ] Myocardial injury, myocarditis, and left ventricular systolic disfunction were frequently recognized and associated with increased morbidity but not mortality. [ 18 ] Due to this phenomenon, AMI as a rare cardiac disease in scrub typhus was easily misdiagnosed.…”

Cardiovascular Risks Associated with Patients Infected with Scrub Typhus: A Nationwide Cohort Study

“…Heart failure syndrome due to acute scrub typhus infection may underestimate in previous literature 16 . In fact, two prospective cohort studies evaluate cardiac manifestations in scrub typhus with echocardiography and cardiac biomarkers, showing 30.9-42.8% patients had reduced ejection fraction; 61.7-72.8% patients had elevated levels of troponin T or creatine kinase-muscle/brain isoenzyme 9,10 . The increased levels of cardiac biomarkers were correlated with the degree of systolic dysfunction.…”

“…The principal pathophysiologic finding of scrub typhus is widespread vasculitis, perivascular inflammation, altered capillary permeability, and microangiopathy in the involved organs 8 . Scrub typhus infection with cardiac involvement is common and have been reported in prospective cohort studies, with reduced left ventricular ejection fraction in 31-43% of patients; elevated cardiac troponin T levels in 62-73% of patients 9,10 . In addition, the abnormal electrocardiogram (ECG) finding of ST-segment changes and T wave inversion were also observed in 9.8-66% and 8.5-12.3% of patients, respectively 9,10 .…”

“…Scrub typhus infection with cardiac involvement is common and have been reported in prospective cohort studies, with reduced left ventricular ejection fraction in 31-43% of patients; elevated cardiac troponin T levels in 62-73% of patients 9,10 . In addition, the abnormal electrocardiogram (ECG) finding of ST-segment changes and T wave inversion were also observed in 9.8-66% and 8.5-12.3% of patients, respectively 9,10 . The degree of prolonged QT interval was found to be associated with the severity of scrub typhus infection 11 .…”