Pleural effusion (PE) may occur during the coronavirus disease (COVID-19) especially in critic patients. The aim of this study is to analyze PE in COVID-19 patients, to understand whether it could be a useful diagnostic tool in suspected cases and to assess the PE impact on prognosis. Between April 8 and May 16 2020, 12 patients with positive nasopharyngeal swab (NPS) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n=7) or suspected (n=5) based on radiological findings showed PE. The pleural fluid was collected and preserved for future analysis. The PE of 6 patients have been tested for SARS-CoV-2.
PE was present at the admission in 3 patients; 4 patients had hydro-pneumothorax related to prolonged positive pressure ventilation and in 5 patients PE occurred during the hospitalization. In positive patients the thoracentesis was performed 21,75±5.4 days after diagnosis; in other suspected 5 after 25±8 days from the onset of symptoms. Among the 6 PE that have been tested, SARS- CoV-2 was detected only in 2 patients with already NPS positive. All of these patients had a concomitant cancer. Four patients had a negative COVID-19 PE; in 3 of them NPS was negative while 1 patients had both NPS and serologic tests positive for SARS-CoV-2. Mortality rate of COVID-19 patients with positive pleural fluid was 50%. The other COVID-19 patient with negative PE died 45 days after the diagnosis. All suspected radiological cases had repeated negative NPS and were transferred on COVID-free wards.
Among this first tested group, SARS-CoV-2 detection on PE seems to be related to positive NPS and don't contributed to diagnosis of COVID-19. The onset of PE in COVID-19 patients represents a negative prognostic factor regardless the presence of SARS-CoV-2 in PE. Future analysis of the preserved pleural fluid and on new samples that will be collect from suspected and COVID-19 patients might be useful to better understand the biological behavior of SARS-CoV-2.
