Pleural effusions in acute idiopathic pericarditis and postcardiac injury syndrome

PURPOSE OF REVIEW: Pleural effusions are frequent in the context of acute idiopathic pericarditis and following pericardiotomy, but they have seldom been characterized. This review summarizes their most relevant clinical features. RECENT FINDINGS: In acute idiopathic pericarditis, pleural effusions tend to be left-sided and, if bilateral, they are usually larger on the left. Less than 5% are unilateral right-sided. About 90% of the effusions occupy less than one-third of the hemithorax, and 99% meet Light's exudative criteria with a predominance of lymphocytes in three fourths of the cases. Although postcardiac injury syndrome (PCIS)-related effusions share similar characteristics, they present some differential features: more than 15% are unilateral on the right (except for Dressler syndrome), one-fourth opacify half or more of the hemithorax, and nearly two thirds are bloody. The combination of nonsteroidal anti-inflammatory drugs and colchicine, along with therapeutic thoracenteses for moderate-to-large effusions, is the mainstay treatment approach. The postoperative use of colchicine is also a reasonable option for preventing PCIS in patients who have undergone cardiac surgery. SUMMARY: Pleural effusions because of pericardial diseases remain a clinical diagnosis. If unilateral right-sided, massive, or transudative effusions are seen, an alternative diagnosis to acute pericarditis should be considered.