A Toolkit for Health Care Professionals Recurrent Pericarditis Initial Investigations Initial investigations in the assessment of inflammatory pericarditis include blood tests, electrocardiography and echocardiography. (See “Multimodality Imaging” on page 14.) Baseline blood tests include assessment of a complete blood count looking for neutrophilic leukocytosis, basic metabolic biochemical panel for baseline assessment of renal function and assessment of inflammatory markers, including erythrocyte sedimentation rate (ESR) and CRP. Given the inflammatory nature of recurrent pericarditis, recurrent flares of chest pain should be associated with elevated inflammatory markers. Normal inflammatory markers in the setting of chest pain should prompt evaluation for alternative non-pericarditic causes of chest pain. Troponin elevation may indicate the coexistent presence of myocardial involvement consistent with myopericarditis. Based on the history and clinical examination, consideration should be given to additional testing to determine etiology, including auto-antibody panels looking for autoimmune disease and myeloma screening. Viral serologies should not be performed typically given the ubiquitous nature of causative illnesses. ECG changes occur in approximately 60% of patients presenting with acute pericarditis and suggest coexistent epicardial inflammation. Characteristic ECG changes include widespread concave up ST-segment elevation with PR-segment depression. Typical ECG findings Stage 1, seen in the first hours to days, are characterized by widespread ST elevation (typically concave up) with reciprocal ST depression in leads aVR and V1. These ECG changes evolve with subsequent ST segments normalization with T wave flattening, followed by diffuse T-wave inversions; and, finally, ECG normalization.37 Echocardiography may identify a pericardial effusion, which is typically small, in up to 60% of patients. Additionally, it offers assessment for imaging evidence of cardiac tamponade, which may complicate this condition. CMR offers an additional useful tool in the assessment of inflammatory pericarditis by allowing assessment of pericardial thickness, pericardial delayed gadolinium enhancement and pericardial edema. It is essential that CMR is read by experts in pericardial assessment, as it is not infrequent for epicardial fat to inadvertently be misdiagnosed as delayed gadolinium enhancement of the pericardium. Additionally, it is important to note that following an index episode of acute pericarditis, pericardial delayed gadolinium enhancement is slow to resolve and may persist well beyond 12 months. Hence, the presence of delayed gadolinium enhancement of the pericardium should not be misinterpreted as representing acute pericardial inflammation in the absence of other clinical findings or elevated inflammatory markers. Echocardiography may identify a pericardial effusion, which is typically small, in up to 60% of patients. 13
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