Circulating cardiac biomarkers and echocardiographic abnormalities in patients with scrub typhus: A prospective cohort study from a tertiary care center in North India

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.

Keywords

• scrub typhus; orientia tsutsugamushi; heart failure; cardiac injury; echocardiography; ecg; n-terminal pro-b-type natriuretic peptide; troponin t; ck-mb.