Churg-Strauss syndrome: remember cardiac complications too

Editor – Llewellyn et al describe an important case and overview of Churg-Strauss syndrome (CSS) (Clin Med February 2013 pp103–5). In terms of its multisystem involvement, it is important to also consider cardiac involvement, which was not specifically discussed in the paper. Although the patient had a normal echocardiogram and did not display obvious cardiac involvement, it is important to remember this possibility when treating such cases. Cardiomyopathy is the main independent predictor of death in CSS, with a hazard ratio of 4.11 for death after multivariate analysis.¹ In a large recent retrospective series, cardiomyopathy occurred in over 16% of CSS patients, and interestingly anti-neutrophil cytoplasmic antibody (ANCA) negative patients had more cardiac involvement.¹ The median time to death was 14 months from fatal cardiac events after diagnosis with CSS. Vasculitic lesions can occur in the myocardium and coronary vessels with coronary occlusion and subsequent scarring and fibrosis. Cardiac involvement can therefore present as myocarditis, heart failure, valvular disease (especially mitral regurgitation) and pericardial effusion. This can also be compounded by pulmonary hypertension secondary to lung disease.

An observational study of 32 ambulatory CSS patients detected cardiac involvement in 62%.² In those with abnormal cardiac magnetic resonance imaging (MRI), echocardiography could detect cardiac involvement with 83% sensitivity and 80% specificity. In those with echocardiographic abnormalities, cardiac MRI detected cardiac involvement with 88% sensitivity, but only 72% specificity. Notably, 38% of CSS patients had cardiac involvement (on echocardiography or cardiac MRI) despite the absence of cardiac symptoms and a normal ECG (after controlling for diabetes, hypertension and coronary artery disease). Therefore, echocardiography should be used in all CSS patients (cardiac MRI is an alternative but is not always available or practical in a critical care setting).

In summary, it is important for physicians to look beyond symptoms and an ECG for cardiac involvement in CSS with either echocardiography or cardiac MRI as this has prognostic implications.

• © 2013 Royal College of Physicians