Pericardial involvement in systemic inflammatory diseases

Systemic inflammatory diseases (SIDs) are inflammatory syndromes with involvement of at least two organ systems. Classical SIDs include vasculitis, connective tissue diseases, and granulomatous diseases (box 1).1 The term ‘connective tissue disease’ is increasingly used to designate genetic conditions that affect the structural integrity of connective tissue, such as Marfan syndrome, and not only systemic inflammatory conditions. On this basis, the term ‘rheumatologic disease’ or ‘systemic autoimmune disease’ is adopted instead of ‘connective tissue disease’ in this review. Box 1 ### Main systemic inflammatory diseases #### Vasculitides #### Rheumatologic diseases (also known as connective tissue diseases) #### Granulomatous diseases #### Autoinflammatory diseases Cardiac involvement is not uncommon in SIDs, although major cardiac problems rarely present. Cardiac involvement may affect the pericardium (pericarditis and pericardial effusion), the myocardium (myocarditis, cardiomyopathy, rhythm and conduction disturbances, heart failure), coronary arteries (acute coronary syndromes, ischaemic heart disease), the endocardium (valvular disease, thrombi), and major vessels (aneurysm formation, arterial and venous thrombosis).1 2 The reported frequency of cardiac involvement is variable, depending on the applied diagnostic method and patient selection. Technological improvements in imaging and the increasing spread of diagnostic methods have revealed higher frequencies of cardiac abnormalities in patients with SIDs than in older autopsy studies. The pericardium consists of a double layered sac that provides mechanical protection, reduces the friction between the heart and surrounding structures, and limits the distension of the heart contributing to diastolic coupling of the ventricles. Normally, this function is achieved by the presence of a small amount of pericardial fluid (25–50 ml) produced by the visceral pericardium. Infectious and non-infectious noxa are usually responsible for inflammation of the pericardial layers, with increased production of …