Clinical clues to the causes of large pericardial effusions

PURPOSE: To examine whether the size of the effusion, the presence of tamponade, and inflammatory signs are useful in determining the causes of moderate or severe pericardial effusions. SUBJECTS AND METHODS: All echocardiograms performed at a general hospital between January 1990 and April 1996 were screened for pericardial effusion. Patients with moderate (echo-free space of 10 to 20 mm during diastole) or severe (echo-free space >20 mm) effusions were studied. RESULTS: We identified 322 patients (166 [52%] men, mean [± SD] age 56 ± 17 years [range 15 to 88 years]), 132 (41%) with moderate and 190 (59%) with severe pericardial effusion. The most frequent etiologic diagnoses were acute idiopathic pericarditis (n = 66 [20%]), iatrogenic effusions (n = 50 [16%]), cancer (n = 43 [13%]), and chronic idiopathic pericardial effusion (n = 29 [9%]). In 192 (60%) of the patients, the cause of the effusion was a known medical condition. In the 130 other patients, inflammatory signs were associated with acute idiopathic pericarditis (likelihood ratio = 5.4, P< 0.001), severe effusions without inflammatory signs or tamponade were associated with chronic idiopathic pericardial effusion (likelihood ratio = 20, P< 0.001), and tamponade without inflammatory signs was associated with malignant effusions (likelihood ratio = 2.9, P< 0.01). CONCLUSIONS: In many patients, pericardial effusions are due to a known underlying disease or condition. In patients without underlying diseases, inflammatory signs, the size of effusion, and the presence or absence of cardiac tamponade can be helpful in establishing cause.