Recurrent Pericarditis Recurrent pericarditis is defined as the reappearance of pericardial inflammation after an initial attack of acute pericarditis with an asymptomatic period of 4 weeks or longer The recurrence is thought to be related to a repeat episode of acute pericarditis or an autoimmune response While recurrent pericarditis is seen in 15% to 30% adults, it is uncommon among children.16,22 Symptoms are usually not as severe and findings of pericardial rub, ECG changes, and pericardial effusion are less frequent The pericardial pain is treated using NSAIDs Colchicine or corticosteroids are used for pericardial inflammation The risk of future recurrences increases to 50% after the first recurrence if treated with corticosteroids Colchicine, on the other hand, is useful in preventing future recurrences.13,26,27 A longer course of colchicine therapy for 6 to 12 months is usually recommended.3 Pericarditis refractory to NSAIDs, steroids, and colchicine is challenging and may need immunosuppressive agents such as azathioprine, cyclophosphamide, or intravenous immunoglobulins.3,4,13 Newer agents such as interleukin-1β inhibitor, anakinra, and tumor necrosis factor-α inhibitors are also effective in refractory pericarditis.28–30 Pericardiectomy may be considered for debilitating symptoms despite advanced immunosuppression.3,31 Recurrent pericarditis may be part of a generalized autoinflammatory disease resulting from abnormal activation of the immune system Most extensively studied autoinflammatory syndromes are familial Mediterranean fever (FMF) and tumor necrosis factor receptor-1–associated periodic syndrome (TRAPS).32 Clinically, both the conditions present with fever, rash, polyserositis, arthralgia, and arthritis FMF is an autosomal-recessive disorder due to mutation in a gene on chromosome 16p13 and presents during adolescence and adulthood Colchicine is effective in aborting and preventing its recurrence TRAPS result from mutation in tumor necrosis factor receptor (TNFRSF1A) gene located on chromosome 12p13 and has an autosomal-dominant inheritance.33–35 TRAPS typically has childhood onset Unlike FMF, the inflammation in TRAPS is mediated by tumor necrosis factor and interleukin-1 Steroids may be useful in treating an episode but the inflammation responds poorly to colchicine Tumor necrosis factor-α inhibitor (etanercept) is shown to reduce frequency and severity of flares Refractory cases respond to interleukin- 1 inhibitors (anakinra).28–30 Pericardial Effusion and Cardiac Tamponade All causes of pericarditis can potentially result in pericardial effusion.3,5 Pericardial effusions can be classified based on its onset (acute, subacute, or chronic), distribution (loculated or circumferential), composition (exudative, transudative, blood, or pus), and hemodynamic impact (none, cardiac tamponade, or effusion constrictive).3,4,36–39 Pathophysiology In most clinical conditions with inflammation, infection, or injury, the pericardial fluid is exudative while in cases with fluid overload and elevated systemic venous pressure, it is transudative The hemodynamic consequences of pericardial effusion are determined by the amount of fluid and rapidity of accumulation Gradual accumulation of fluid shifts the pericardial pressurevolume curve to the right As a result, even large effusion has no compressive effect on cardiac chambers and consequently may remain asymptomatic The nonlinear pressure-volume curve of pericardium results in an almost vertical rise in pericardial pressure after an initial slow ascent (see Fig 57.1) This late steep rise in pressure is responsible for “last drop” phenomenon: the final increment of fluid producing critical cardiac compression while the first decrement during pericardial drainage leads to the largest relative decompression.4 Cardiac filling is altered as the cardiac chambers compete with the pericardial fluid in the relatively fixed pericardial space The filling pressures in cardiac chambers are elevated and are equal to intrapericardial pressure Elevated filling pressures limit the early diastolic filling of the ventricles and manifests as a distinctive loss of “y” descent in jugular venous pressure (JVP).3,4 Due to fixed cardiac volume, the atriums can fill only during the phase of ventricular systole when the blood exits the heart This explains preserved “x” descent in JVP in patients with cardiac tamponade Pericardial fluid allows normal transmission of thoracic pressure to cardiac chambers As a result, during inspiration, the right ventricle is preferentially filled while constrains of fixed cardiac volume limit left ventricular filling The filling of the left and right ventricle, therefore, is 180 degrees out of phase with