cardiovascular disorders
Pericarditis
Pathophysiology of Pericarditis
Pericarditis may be Acute Subacute Chronic Acute pericarditisdevelops quickly, causing inflammation of the pericardial sac and often a pericardial effusion. Inflammation can extend to the epicardial myocardium (myopericarditis). Adverse hemodynamic effects and rhythm disturbance are rare, although cardiac tamponade is possible. Acute disease may resolve completely, resolve and reoccur (up to 30% of acute cases) or become subacute or chronic. These forms develop more slowly; their prominent feature is effusion. Subacute pericarditisoccurs within weeks to months of an inciting event. Chronic pericarditisis defined as pericarditis persisting > 6 months. Pericardial effusionis accumulation of fluid in the pericardium. The fluid may be serous fluid (sometimes with fibrin strands), serosanguineous fluid, blood, pus, or chyle. Cardiac tamponadeoccurs when a large pericardial effusion impairs cardiac filling, leading to low cardiac output and sometimes shock and death. If fluid (usually blood) accumulates rapidly, even small amounts (eg, 150 mL) may cause tamponade because the pericardium cannot stretch quickly enough to accommodate it. Slow accumulation of up to 1500 mL may not cause tamponade. Loculated effusion may cause localized tamponade on the right or left side of the heart. Occasionally, pericarditis causes a marked thickening and stiffening of the pericardium (constrictive pericarditis). which is now less common than in the past, results from marked inflammatory, fibrotic thickening of the pericardium. Sometimes the visceral and parietal layers adhere to each other or to the myocardium. The fibrotic tissue often contains calcium deposits. The stiff, thickened pericardium markedly impairs ventricular filling, decreasing stroke volume and cardiac output. Significant pericardial fluid accumulation is rare. Rhythm disturbance is common. The diastolic pressures in the ventricles, atria, and venous beds become virtually the same. Systemic venous congestion occurs, causing considerable transudation of fluid from systemic capillaries, with dependent edema and, later, ascites. Chronic elevation of systemic venous pressure and hepatic venous pressure may lead to liver scarring, called cardiac cirrhosis, in which case, patients may initially present for evaluation of Cirrhosis . Constriction of the left atrium, the left ventricle, or both may elevate pulmonary venous pressure. Occasionally, There are several variants of constrictive pericarditis: Chronic constrictive pericarditis, usually requiring pericardiectomy as definitive treatment Subacute (early stage) constrictive pericarditis,developing weeks to months after an inciting injury and managed initially with medical therapy Transient constrictive pericarditis (typically subacute), is that which resolves spontaneously or after medical therapy Effusive-constrictive pericarditis characterized by pericardial constriction involving the visceral pericardium with significant pericardial effusion sometimes requiring treatment for Cardiac Tamponade None 