QJM Advance Access originally published online on December 5, 2005
QJM 2006 99(1):23-31; doi:10.1093/qjmed/hci150
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Clinical features remain important for the diagnosis of infective endocarditis in the modern era
From the 1University of Edinburgh, Cardiology Department, Western General Hospital, and 2Public Health Sciences, University of Edinburgh Medical School, Edinburgh, UK
Address correspondence to Dr M.A. Denvir, University of Edinburgh, Cardiology Department, Western General Hospital, Crewe Road, Edinburgh EH4 2XU. email: mdenvir{at}staffmail.ed.ac.uk
Received 15 April 2005 and in revised form 14 November 2005
Background: Infective endocarditis (IE) can be difficult to diagnose, due to multiple (often non-specific) presenting features.
Aim: To assess the predictive accuracy of classical clinical features and blood investigations readily available at the time of presentation.
Design: Cross-sectional analysis.
Methods: We studied 29 IE cases and 79 controls (clinically suspicious contemporaneous cases where IE was subsequently excluded) from a hospital-based group of patients referred to a cardiac department with possible infective endocarditis. Patients were identified from the echocardiography database. Cases were defined by final diagnosis. Symptoms, signs, risk factors for IE and blood investigations were recorded from case notes and examined by univariate and multivariate analyses.
Results: The sensitivity, specificity, and positive and negative predictive values of transthoracic echocardiography (TTE) for detection of IE in clinically suspected cases were 71%, 98%, 57% and 99%, respectively. Univariate analyses revealed a significant association between IE and several clinical features. Under multivariate analysis, previous heart valve surgery (OR 13.3, 90%CI 3.2–55.6), positive blood cultures (OR 17.2, 90%CI 4.9–58.8), signs of embolism (OR 11.4, 90%CI 3.0–43.5), a new, altered or changing murmur (OR 10.3, 90%CI 2.8–38.5) and splenomegaly (OR 18.2, 90%CI 3.6–90.9) were independent predictors for IE.
Discussion: Clinical features at presentation continue to be important for the diagnosis of IE. Features such as positive blood cultures, signs of embolism and a changing heart murmur should be used to guide investigation and treatment of IE prior to echocardiography, or when TTE is negative.