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.
Although a relevant number of Coronavirus Disease-2019 (COVID-19) patients presented an interstitial pneumonia as main clinical feature, acute respiratory distress syndrome, pulmonary edema, multiple organ failure, or even death has been reported.
Feng Y et al divided patients in three clinical groups (moderate, severe, and critical group) according to the fifth version of the guidelines issued by the National Health Commission of China on Diagnosis and Treatment of COVID-19. Severe patients presented at least one within following clinical conditions: respiratory distress with respiratory rate >30 per min; Oxygen saturation on room air at rest 75 years) was a risk factor for mortality.
Li K. et al reported that severe/critical patients were significantly older and had more comorbidities (diabetes mellitus and chronic obstructive pulmonary disease) compared to mild group. The severe/critical group had higher incidences of dyspnea, probably related to the severe alveolar damage and chest pain which may result from the inflammatory pleural involvement. Severe/critical patients presented decreased lymphocytes could be used as an important index in the evaluation of disease severity. The Author suggested that an effective treatment of severe and critical cases is the key to reduce complications and mortality. Basic disease treatment, secondary infection prevention, and timely organ function support are needed for them. Therefore, it is very important to find the related factors of disease severity in clinical practice.
Presence of pleural effusion in COVID-19 patients is rare with a prevalence of 5.88% in COVID-19 population. A case of asymptomatic patient with small bilateral pleural effusion has been reported. But critical/severe patients case series reported a prevalence of pleural effusion up to 28%. Previous studies showed that pleural effusion was a poor prognostic indicator in H5N1 infection too.
Critical patients usually presented poor prognosis and high mortality. Analysis of clinical and imaging features in this setting could improve knowledge of mechanism of severe/critical conditions and promote its prompt clinical diagnosis and treatment.
It has been reported that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be detected in specimens from other sites. The presence of SARS-CoV-2 in pleural fluid has been detected by Lescure et al on a critical patients on day 12 from the onset of symptoms (5 days after the first positive nasopharyngeal swab). SARS-CoV-2 detection on pleural fluid has never be found on negative nasopharyngeal swab patient and it had never contributed to diagnosis of COVID-19.
Our study could contribute to better understand the biological behavior of SARS-CoV-2, above all in critical patients were a prompt clinical diagnosis and treatment could reduce morbidity and mortality.