Acute pericarditis, an acute inflammation of the parietal and visceral surfaces of the pericardium, may be infectious or noninfectious and can be associated with pericardial effusion. Viral infections are the most common etiology, particularly in infancy (eg, Coxsackie B virus, Adenovirus, enteroviruses, echoviruses, cytomegalovirus, HIV, influenza virus). Other etiologies include but are not limited to acute rheumatic fever, purulent pericarditis (eg, S aureus, S pneumoniae, Haemophilus influenzae, Neisseria meningitides, and streptococci), tuberculosis (constrictive pericarditis), heart surgery (postpericardiotomy syndrome), collagen vascular diseases (eg, rheumatoid arthritis), and uremia (uremic pericarditis). Pericardial effusion may be sero-fibrinous, hemorrhagic, or purulent. Effusion may be completely absorbed or may result in pericardial thickening or chronic constriction (constrictive pericarditis). A rapid accumulation of a large amount of fluid produces cardiac tamponade that is classically associated with a triad of low arterial blood pressure, jugular venous distention, and distant, muffled heart sounds (Beck triad). Narrowed pulse pressure and pulsus paradoxus may be observed. Cardiac tamponade occurs more commonly with purulent pericarditis.
History may reveal preceding upper respiratory tract infection. Fever and chest pain may be present. Chest pain may be relieved by leaning forward and may be made worse by supine position or deep inspiration. Pericardial friction rub (a grating to-and-fro sound in phase with the heart sounds) is the cardinal physical sign. Heart murmur is usually absent. Presence of a cardiac murmur should alert the consideration of acute rheumatic fever or endocarditis.