Pericardial effusion has several etiologies, such as primary pericardial diseases, cardiac surgery, trauma and systemic conditions, including hypothyroidism, renal failure, chronic neoplastic infiltration, autoimmune inflammation, systemic lupus erythematosus, and rheumatoid arthritis.’ Queiroz et al., published an interesting paper on 254 patients with pericardial effusion at a quaternary institution, 40.4% with severe pericardial effusion and 44.1% with cardiac tamponade. Retrospective cohorts of critically ill patients are rare in the literature. The most frequent etiology was idiopathic, but postoperative, neoplasia, and postinterventional procedures were also common. Although the main etiology is idiopathic in developed countries, infectious causes are prominent in developing countries, such as tuberculosis, which reaches a frequency above 60%. During the current COVID-19 pandemic, SARS-CoV-2 is of great importance in etiological investigation.

In Queiroz et al., pericardial effusion was diagnosed by echocardiography, a widely available and inexpensive method that can be performed at bedside. In addition to clinical and epidemiological aspects, Doppler echocardiography, magnetic resonance imaging, nuclear medicine tests, and laboratory analysis of the pericardial fluid could provide additional information about the etiology. However, the gold standard diagnostic exam is pericardial biopsy, which is indicated for diagnostic investigation in patients with persistent pericarditis refractory to clinical treatment and no definitive diagnosis.

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