Unilateral Pleural Effusions with More Than One Apparent Etiology. A Prospective Observational Study

Frequent association of malignant effusions in plasmablastic lymphoma: a single-institutional experience of nine cases in Taiwan

PURPOSE

Plasmablastic lymphoma (PBL) is a rare, aggressive lymphoma that is characterized by terminal B-cell differentiation. In the West, PBL usually occurs in patients with immunodeficiencies, particularly those induced by human immunodeficiency virus (HIV) infection. We investigated the clinicopathological features of PBL at a single institute in Taiwan, where HIV infection is rare.

METHODS

This retrospective chart review identified PBL cases that were treated at a single institute in southern Taiwan between 2008 and 2024.

RESULTS

We identified nine patients (four males and five females; median age 71 years). Of the eight patients tested for HIV, only one tested positive. Pathologically, the tumors showed plasmablastic morphology and immunophenotype, and three (33%) cases tested positive for Epstein-Barr virus. Six (67%) patients presented with Stage IV disease, including five (56%) with malignant effusion. Six patients were treated with chemotherapy and the remaining three received only supportive care. During a median follow-up of 10 months, five patients died of progressive disease, two died of unrelated diseases, and two were alive with PBL relapse.

CONCLUSION

In Taiwan, PBL constitutes a rare and aggressive clinical condition and is frequently associated with malignant effusion. In contrast to Western patients, the PBL in most patients from Taiwan was unrelated to HIV infection.

ERS statement on benign pleural effusions in adults

The incidence of non-malignant pleural effusions far outweighs that of malignant pleural effusions and is estimated to be at least 3-fold higher. These so-called benign effusions do not follow a "benign course" in many cases, with mortality rates matching and sometimes exceeding those of malignant pleural effusions. In addition to the impact on patients, healthcare systems are also significantly affected, with recent US epidemiological data demonstrating that 75% of resource allocation for pleural effusion management is spent on non-malignant pleural effusions (excluding empyema). Despite this significant burden of disease, and by existing at the junction of multiple medical specialties, reflecting a heterogenous constellation of medical conditions, non-malignant pleural effusions are rarely the focus of research or the subject of management guidelines. With this European Respiratory Society Task Force, we assembled a multispecialty collaborative across 11 countries and three continents to provide a statement based on systematic searches of the medical literature to highlight evidence in the management of the following clinical areas: a diagnostic approach to transudative effusions, heart failure, hepatic hydrothorax, end-stage renal failure, benign asbestos-related pleural effusion, post-surgical effusion and nonspecific pleuritis.

DUETS for Light's in separating exudate from transudate

BACKGROUND

Fifty years since its inception, Light's criteria have aided in classifying pleural effusions (PEs) as exudates if 1 or more criteria are met. Thoracic ultrasound (US) emerges as a non-invasive technique for point of care use especially if pleural procedures are contemplated.

OBJECTIVE

We aimed to develop a score based on radiological and US features that could separate exudates from transudates without serum and pleural fluid biochemical tests necessary for Light's criteria.

METHODS

A prospective review of consecutive patients with PE who underwent thoracocentesis was performed. CXRs were evaluated for laterality followed by US for echogenicity, pleural nodularity, thickening and septations. PE was classified as exudate or transudate according to Light's criteria and corroborated with albumin gradient. A score combining radiological and US features was developed.

RESULTS

We recruited 201 patients with PE requiring thoracocentesis. Mean age was 64 years, 51% were females, 164 (81.6%) were exudates, and 37 (18.4%) were transudates. Assigning 1-point for Diaphragmatic nodularity, Unilateral, Echogenicity, Pleural Thickening and Septations, DUETS ranged from 1 to 5. DUETS ≥2 indicated high likelihood for exudate (PPV 98.8%, NPV 100%) with 1% misclassification versus 6.9% using Light's criteria (p < 0.001).

CONCLUSION

DUETS separated exudates from transudates with good accuracy, and could obviate paired serum and pleural fluid tests necessary for Light's criteria computation. Our study reflected real world practice where DUETS performed better than Light's criteria for PE that arose from more than one disease processes, and in the evaluation of patients with PE who have received diuretics.

Elusive Unilateral Pleural Effusion: Keys to Clinching the Diagnosis

Unilateral pleural effusions may sometimes be difficult to diagnose. The cause may vary widely, including congestive heart failure, chronic liver and kidney disease, various drugs, and underlying undiagnosed disorders of the lung and pleura. With advancements in chest imaging, new biomarkers, and less invasive methods for obtaining tissue samples, it may be possible to identify the cause of the unilateral pleural effusions whose etiology is unclear. Even reviewing patient history, re-examining pleural fluid, classifying effusions based on Light's criteria, and ruling out pseudoexudates can help understand the cause. We aim to discuss a case of unilateral pleural effusion and, on its backdrop, discuss an approach to elusive unilateral pleural effusion.

Clinical overview of the physiology and pathophysiology of pleural fluid movement: a narrative review

In physiological conditions, the pleural space couples the lung with the chest wall and contains a small amount of fluid in continuous turnover. The volume of pleural fluid is the result from the balance between the entry of fluid through the pleural capillaries and drainage by the lymphatics in the most dependent areas of the parietal pleura. Fluid filtration is governed by Starling forces, determined by the hydrostatic and oncotic pressures of the capillaries and the pleural space. The reabsorption rate is 28 times greater than the rate of pleural fluid production. The mesothelial layer of the inner lining of the pleural space is metabolically active and also plays a role in the production and reabsorption of pleural fluid. Pleural effusion occurs when the balance between the amount of fluid that enters the pleural space and the amount that is reabsorbed is disrupted. Alterations in hydrostatic or oncotic pressure produce a transudate, but they do not cause any structural damage to the pleura. In contrast, disturbances in fluid flow (increased filtration or decreased reabsorption) produce an exudate via several mechanisms that cause damage to pleural layers. Thus, cellular processes and the inflammatory and immune reactions they induce determine the composition of pleural fluid. Understanding the underlying pathophysiological processes of pleural effusion, especially cellular processes, can be useful in establishing its aetiology.

Fluoroscopy-Guided Percutaneous Transthoracic Pleural Forceps Biopsy in Patients With Exudative Pleural Effusion

OBJECTIVE

This study aimed to evaluate the diagnostic performance and procedural characteristics of fluoroscopy-guided percutaneous transthoracic pleural forceps biopsy (PTPFB) in patients with exudative pleural effusion.

MATERIALS AND METHODS

Patients with exudative pleural effusion who underwent PTPFB between May 1, 2014, and February 28, 2023, were included in this retrospective study. The interval between percutaneous catheter drainage (PCD) and PTPFB, number of biopsies, procedural time, and procedure-related complications were evaluated. The sensitivity, specificity, and accuracy of diagnosing malignancy were computed for pleural cytology using PCD drainage, PTPFB, and combined PTPFB and pleural cytology.

RESULTS

Seventy-one patients, comprising 50 male and 21 female (mean age, 69.5 ± 15.3 years), were included in this study. The final diagnoses were benign lesions in 48 patients (67.6%) and malignant in 23 patients (32.4%). The overall interval between PCD and biopsy was 2.4 ± 3.7 days. The interval between PCD and biopsy in the group that underwent delayed PTPFB was 5.2 ± 3.9 days. The mean number of biopsies was 4.5 ± 1.3. The mean procedural time was 4.4 ± 2.1 minutes. Minor bleeding complications were reported in one patient (1.4%). The sensitivity, specificity, and accuracy for pleural cytology, PTPFB, and combined PTPFB and pleural cytology were 47.8% (11/23), 100% (48/48), and 83.1% (59/71), respectively; 65.2% (15/23), 100% (48/48), and 88.7% (63/71), respectively; and 78.3% (18/23), 100% (48/48), and 93.0% (66/71), respectively. The sensitivity and accuracy of cytology combined with PTPFB were significantly higher than those of cytological testing alone (P = 0.008 and 0.001, respectively).

CONCLUSION

Fluoroscopy-guided PTPFB is an accurate and safe diagnostic technique for patients with exudative pleural effusion, with acceptable diagnostic performance, low complication rates, and reasonable procedural times.

Ultrasound in predicting improvement in dyspnoea after therapeutic thoracentesis in patients with recurrent unilateral pleural effusion

Background

In patients with recurrent pleural effusion, therapeutic thoracentesis is one way of relief. Correct prediction of which patients will experience relief following drainage may support the management of these patients. This study aimed to assess the association between ultrasound (US) characteristics and a relevant improvement in dyspnoea immediately following drainage.

Methods

In a prospective, observational study, patients with recurrent unilateral pleural effusion underwent US evaluation of effusion characteristics and diaphragm movement measured by M-mode and the Area method before and right after drainage. The level of dyspnoea was assessed using the modified Borg scale (MBS). A minimal important improvement in dyspnoea was defined as delta MBS ≥ 1.

Results

In the 104 patients included, 53% had a minimal important improvement in dyspnoea following thoracentesis. We found no association between US-characteristics, including diaphragm shape or movement (M-mode or the Area method), and a decrease in dyspnoea following drainage. Baseline MBS score ≥ 4 and a fully drained effusion were significant correlated with a minimal important improvement in dyspnoea (OR 3.86 (1.42-10.50), p = 0.01 and 2.86 (1.03-7.93), p = 0.04, respectively).

Conclusions

In our study population, US-characteristics including assessment of diaphragm movement or shape was not associated with a minimal important improvement in dyspnoea immediately following thoracentesis.

Diagnostic accuracy of thoracic CT to differentiate transudative from exudative pleural effusion prior to thoracentesis

BACKGROUND

Computed tomography (CT) scan is commonly performed for pleural effusion diagnostis in the clinic. However, there are limited data assessing the accuracy of thoracic CT for the separation of transudative from exudative effusions. The study aimed to determine the diagnostic value of thoracic CT in distinguishing transudates from exudates in patients with pleural effusion.

METHODS

This is a two-center retrospective analysis of patients with pleural effusion, a total of 209 patients were included from The First Affiliated Hospital of Henan University of Science and Technology as the derivation cohort (Luoyang cohort), and 195 patients from the First Affiliated Hospital of Zhengzhou University as the validation cohort (Zhengzhou cohort). Patients who underwent thoracic CT scan followed by diagnostic thoracentesis were enrolled. The optimal cut-points of CT value in pleural fluid (PF) and PF to blood CT value ratio for predicting a transudative vs. exudative pleural effusions were determined in the derivation cohort and further verified in the validation cohort.

RESULTS

In the Derivation (Luoyang) cohort, patients with exudates had significantly higher CT value [13.01 (10.01-16.11) vs. 4.89 (2.31-9.83) HU] and PF to blood CT value ratio [0.37 (0.27-0.53) vs. 0.16 (0.07-0.26)] than those with transudates. With a cut-off value of 10.81 HU, the area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CT value were 0.85, 88.89%, 68.90%, 43.96%, and 95.76%, respectively. The optimum cut-value for PF to blood CT value ratio was 0.27 with AUC of 0.86, yielding a sensitivity of 61.11%, specificity of 86.36%, PPV of 78.57%, and NPV of 73.08%. These were further verified in the Validation (Zhengzhou) cohort.

CONCLUSIONS

CT value and PF to blood CT value ratio showed good differential abilities in predicting transudates from exudates, which may help to avoid unnecessary thoracentesis.

Effect of sugammadex on postoperative complications in patients with severe burn who underwent surgery: a retrospective study

This retrospective study investigated the association of sugammadex with postoperative pulmonary complication risk between 2013 and 2021 in patients with severe burn of five hospitals. Postoperative pulmonary complications included atelectasis, pulmonary edema, pulmonary effusion, pneumothorax, pneumonia, pulmonary thromboembolism, respiratory failure and acute respiratory distress. To identify whether sugammadex reduced the risk of postoperative pulmonary complication in patients with severe burn who underwent surgery, Kaplan-Meier curve were used to check the difference of incidence according to surgical cases and time-varying Cox hazard regression were used to calculate the hazard ratio. The study included 1213 patients with severe burn who underwent 2259 surgeries. Postoperative pulmonary complications were occurred in 313 (25.8%) patients. Among 2259 surgeries, sugammadex was used in 649 (28.7%) surgeries. Cumulative postoperative pulmonary complication were 268 (16.6%) cases in surgeries without sugammadex, and 45 (6.9%) cases in surgeries with sugammadex, respectively (P < 0.005). The postoperative pulmonary complications risk was reduced significantly in patients who use sugammadex than those who did not use sugammadex. (Adjusted hazard ratio, 0.61; 95% confidence interval, 0.42-0.89; P = 0.011). In conclusion, sugammadex reduced risk of postoperative pulmonary complications compared with nonuse of sugammadex in patients with severe burn who underwent surgery.

Expert Review on Contemporary Management of Common Benign Pleural Effusions

Heart failure (HF) and cirrhosis are frequently associated with pleural effusions (PEs). Despite their apparently benign nature, both HF-related effusions and hepatic hydrothorax (HH) have poor prognosis because they represent an advanced stage of the disease. Optimization of medical therapy in these two entities involve not only the use of diuretics, but also other pharmacological therapies. For instance, all HF patients with reduced or mildly reduced left ventricular ejection fraction can benefit from angiotensin receptor-neprilysin inhibitors, beta blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter 2 inhibitors. Conversely, it is better for HH patients to avoid nonselective beta blockers. Refractory cardiac- and cirrhosis-related PEs are commonly managed by iterative therapeutic thoracentesis. When repeated aspirations are needed, thereby diminishing quality of life, the insertion of an indwelling pleural catheter (IPC) may be warranted. However, in selected HH patients who are diuretic-resistant or diuretic-intractable, placement of transjugular intrahepatic portosystemic shunts should be considered as a bridge to liver transplantation, whereas in transplant candidates the role of IPC is debatable. Another benign condition, pleural tuberculosis (TB) is a serious health problem in developing countries. Diagnostic certainty is still a concern due to the paucibacillary nature of the infection, although the use of more sensitive nucleic acid amplification tests is becoming more widespread. Its treatment is the same as that of pulmonary TB, but the potential drug interactions between antiretroviral and anti-TB drugs in HIV-coinfected patients as well as the current recommended guidelines for the different types of anti-TB drugs resistance should be followed.

Parapneumonic effusions related to Streptococcus pneumoniae: serotype and disease severity trends from 2006 to 2018 in Bristol, UK

RATIONALE

Streptococcus pneumoniae epidemiology is changing in response to vaccination and some data suggest that empyema incidence is increasing. However, differences exist between the UK and US studies. We describe trends in the clinical phenotype of adult pneumococcal pleural infection, including simple parapneumonic effusions (SPE) in the pneumococcal conjugate vaccination (PCV) era.

OBJECTIVES

To determine whether there were differences in pneumococcal disease presentation and severity associated with pleural infection.

METHODS

A retrospective cohort study, all adults ≥16 years admitted to three large UK hospitals, 2006-2018 with pneumococcal disease. 2477 invasive pneumococcal cases were identified: 459 SPE and 100 pleural infection cases. Medical records were reviewed for each clinical episode. Serotype data were obtained from the UK Health Security Agency national reference laboratory.

RESULTS

Incidence increased over time, including non-PCV-serotype disease. PCV7-serotype disease declined following paediatric PCV7 introduction, but the effect of PCV13 was less apparent as disease caused by the additional six serotypes plateaued with serotypes 1 and 3 causing such parapneumonic effusions from 2011 onwards.Patients with pleural infection had a median survival 468 days (95% CI 340 to 590) vs 286 days (95% CI 274 to 335) in those with SPE. Pleural infection associated with frank pus had lower 90-day mortality than pleural infection without pus (0% vs 29%, p<0.0001). 90-day mortality could be predicted by baseline increased RAPID (Renal, Age, Purulence, Infection source, and Dietary factors) score (HR 15.01, 95% CI 1.24 to 40.06, p=0.049).

CONCLUSIONS

Pneumococcal infection continues to cause severe disease despite the introduction of PCVs. The predominance of serotype 1 and 3 in this adult UK cohort is in keeping with previous studies in paediatric and non-UK studies. Rising non-PCV serotype disease and limited impact of PCV13 on cases caused by serotypes 1 and 3 offset the reductions in adult pneumococcal parapneumonic effusion disease burden observed following the introduction of the childhood PCV7 programme.

Optimal diagnostic strategies for pleural diseases and identifying high-risk patients

INTRODUCTION

Pleural diseases encompass a broad range of conditions with diverse and heterogenous etiologies. Diagnostics in pleural diseases thus represents a challenging field with a wide array of available testing to distinguish between the numerous causes of pleural disease. Nonetheless, deploying best practice diagnostics in this area is essential in reducing both duration o the investigation pathway and symptom burden.

AREAS COVERED

This article critically appraises the optimal diagnostic strategies and pathway in patients with pleural disease, reviewing the latest evidence and key practice points in achieving a treatable diagnosis in patients with pleural disease. We also cover future and novel directions that are likely to influence pleural diagnostics in the near future. PubMed was searched for articles related to pleural diagnostics (search terms below), with the date ranges including June 2012 to June 2022.

EXPERT OPINION

No single test will ever be sufficient to provide a diagnosis in pleural conditions. The key to reducing procedure burden and duration to diagnosis lies in personalizing the investigation pathway to patients and deploying tests with the highest diagnostic yield early (such as pleural biopsy in infection and malignancy). Novel biomarkers may also allow earlier diagnostic precision in the near future.

Diagnosis and Treatment of Pleural Effusion. Recommendations of the Spanish Society of Pulmonology and Thoracic Surgery. Update 2022

Pleural effusion (PE) is a common yet complex disease that requires specialized, multidisciplinary management. Recent advances, novel diagnostic techniques, and innovative patient-centered therapeutic proposals have prompted an update of the current guidelines. This document provides recommendations and protocols based on a critical review of the literature on the epidemiology, etiology, diagnosis, prognosis, and new therapeutic options in PE, and addresses some cost-effectiveness issues related to the main types of PE.

Pleural homocysteine for malignant pleural effusion: A prospective and double-blind diagnostic test accuracy study

OBJECTIVE

To assess the accuracy of pleural fluid homocysteine for discriminating malignant pleural effusion (MPE) and benign pleural effusion (BPE).

METHODS

A total of 194 patients from two cohorts (Hohhot and Changshu) with undiagnosed pleural effusion were prospectively enrolled. Their pleural homocysteine was measured, and its diagnostic accuracy and net benefit for MPE were analyzed by receiver operating characteristic (ROC) curve analysis and decision curve analysis, respectively.

RESULTS

In the Hohhot cohort (n = 136) and the Changshu cohort (n = 58), MPE patients had significantly higher homocysteine levels than BPE patients. The areas under the ROC curves of homocysteine for the diagnosis of MPE were 0.61 (p = 0.027) and 0.59 (p = 0.247), respectively. The decision curves of homocysteine were close to the reference line in both the Hohhot cohort and the Changshu cohort.

CONCLUSION

The diagnostic accuracy of pleural fluid homocysteine for MPE was low.

Pleural Fluid Analysis: Are Light's Criteria Still Relevant After Half a Century?

Fifty years from their initial description, Light's criteria are still unhesitatingly accepted as the default reference test for separating pleural transudates and exudates. Efforts should be focused not so much on trying to find an even more reliable technique for categorizing PEs but on improving the misclassification rate of transudates that characterize Light's criteria. Despite their shortcomings, Light's criteria may well continue their reign for another 50 years. Long live the Light's criteria!

Modern day management of a unilateral pleural effusion

Over 50 systemic conditions may affect the pleura and, thus, unilateral pleural effusions may present for a variety of reasons. Investigating the cause is essential to providing appropriate management. Various pleural interventions are available in current practice, but have varying diagnostic sensitivity. It is, therefore, vital to consider the intervention with the highest diagnostic yield appropriate to the particular clinical situation. The diagnostic pathway in unilateral pleural effusion is increasingly outpatient based, avoiding hospitalisation, which is particularly relevant with the recent COVID-19 pandemic.

Associated Pleural and Pericardial Effusions: An Extensive Differential Explored

Concurrent pleural and pericardial effusions are not an unusual finding, but their differential diagnosis remains uncertain. Medline-based review identified an extensive list of infectious, inflammatory, neoplastic, iatrogenic, and myriad other etiologies. A single retrospective study had addressed this presentation. Several principles of a diagnostic workup are suggested, acknowledging that a significant minority of patients may not require a comprehensive workup and remain 'idiopathic'.

Exposure to PM2.5 is associated with malignant pleural effusion in lung cancer patients

Air pollution has been recognized to be a risk factor for lung cancer. The objective of this study was to investigate the effects of air pollution on heavy metal alterations in the pleural effusion of lung cancer patients. Pleural effusion was collected from patients with lung cancer and congestive heart failure (CHF). One-year average levels of particulate matter with an aerodynamic diameter of < 10 µm (PM₁₀), PM_2.5, NO₂, and SO₂ were linked to the exposure of these subjects. Traffic-related metals, included Al, Fe, Cu, Zn, and Pb, were determined in the pleural effusion. Logistic regression models were used to examine their associations. There were 63 lung cancer patients and 31 CHF patients enrolled in the current study. We found that PM₁₀, PM_2.5, and NO₂ were negatively correlated with Al in the pleural effusion, whereas PM_2.5 was positively correlated with Zn in the pleural effusion. Increases in 1 μg/m³ of PM_2.5 and 1 ng/mL of Zn were associated with lung cancer (adjusted OR=2.394, 95% CI= 1.446-3.964 for PM_2.5; adjusted OR=1.003, 95% CI=1.000-1.005 for Zn). Increases in PM_2.5 and Zn in the pleural effusion increased the risk of malignant pleural effusion in lung cancer patients (adjusted OR=1.517; 95% CI=1.082-2.127 for PM_2.5; adjusted OR=1.002, 95% CI=1.000-1.005 for Zn). Furthermore, we observed that adenocarcinomas increased in association with a 1-μg/m³ increase in PM_2.5 (crude OR=1.683; 95% CI=1.006-2.817) in lung cancer patients. In conclusion, PM_2.5 exposure and the possible resultant Zn in the pleural effusion associated with the development of malignant pleural effusion in lung cancer.

Diagnostics in Pleural Disease

Pleural disease diagnostics represent a sprawling topic that has enjoyed a renaissance in recent years from humble beginnings. Whilst pleural patients are heterogeneous as a population and in the aetiology of the disease with which they present, we provide an overview of the typical diagnostic approach. Pleural fluid analysis is the cornerstone of the diagnostic pathway; however, it has many shortcomings. Strong cases have been made for more invasive upfront investigations, including image-guided biopsies or local anaesthetic thoracoscopy, in selected populations. Imaging can guide the diagnostic process as well as act as a vehicle to facilitate therapies, and this is never truer than with the recent advances in thoracic ultrasound.

The cytopathological spectrum of lymphomas in effusions in a tertiary center in Taiwan

Lymphomas presenting in effusions could either be primary or secondary, with very limited data from Taiwan.

METHODS

We retrospectively reviewed effusion lymphomas from our archives in a tertiary center from July 2011 to June 2019.

RESULTS

We identified 59 specimens from 43 patients, including 7 cases with primary effusion lymphoma (PEL) and 36, secondary effusion involvement. Half of the secondary cases presented concurrently with effusion lymphoma, while the remaining half-experienced effusion lymphoma during disease progression. All patients with PELs were males with a median age of 77 and presented with massive pleural effusion. None was HIV-related. Two (29%) PEL cases were positive for human herpes virus 8 (HHV8). The only case with plasmablastic phenotype in the PEL group was positive for both HHV8 and EBV. Four patients died shortly after diagnosis; while the remaining three were alive at the last follow-up (two at 13 months and one at 99 months). Of the secondary cases, diffuse large B-cell lymphoma/high grade B-cell lymphoma was the most common (n = 16, 44%), followed by mantle cell lymphoma (n = 5, 14%). Only 8 cases (22%) were T-cell neoplasms. Prognosis for patients with secondary effusion involvement was dismal, with 1- and 2-year overall survival rates at 17% and 8%, respectively.

CONCLUSION

We found a wide cytopathological spectrum of effusion lymphoma in Taiwan. Most of our PEL cases were distinct from that defined in the World Health Organization scheme by a B-cell phenotype, HHV8-negativity, and absence of immunodeficiency. As compared to PEL cases, the prognosis of those with secondary involvement was extremely poor.

Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment

BACKGROUND

Pleural effusion is common in routine medical practice and can be due to many different underlying diseases. Precise differential diagnostic categorization is essential, as the treatment and prognosis of pleural effusion largely depend on its cause.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and on the authors' personal experience.

RESULTS

The most common causes of pleural effusion are congestive heart failure, cancer, pneumonia, and pulmonary embolism. Pleural fluid puncture (pleural tap) enables the differentiation of a transudate from an exudate, which remains, at present, the foundation of the further diagnostic work-up. When a pleural effusion arises in the setting of pneumonia, the potential devel- opment of an empyema must not be overlooked. Lung cancer is the most common cause of malignant pleural effusion, followed by breast cancer. Alongside the treatment of the underlying disease, the specific treatment of pleural effusion ranges from pleurodesis, to thoracoscopy and video-assisted thoracoscopy (with early consultation of a thoracic surgeon), to the placement of a permanently indwelling pleural catheter.

CONCLUSION

The proper treatment of pleural effusion can be determined only after meticulous differential diagnosis. The range of therapeutic options has recently become much wider. More data can be expected in the near future concerning diagnostic test- ing for the etiology of the effusion, better pleurodetic agents, the development of interventional techniques, and the genetic background of the affected patients.

A Study Investigating Markers in PLeural Effusion (SIMPLE): a prospective and double-blind diagnostic study

INTRODUCTION

Serum and fluid laboratory markers are valuable for exploring the aetiologies of pleural effusion (PE) because of their relative non-invasiveness, low cost, objective result and short turnaround time. The diagnostic accuracy of these potential markers needs to be rigorously evaluated before their widespread application in clinical practice. Here, we plan to perform a Study Investigating Markers in PLeural Effusion (SIMPLE).

METHODS AND ANALYSIS

This is a prospective and double-blind clinical trial which is being performed at the Affiliated Hospital of Inner Mongolia Medical University, China. Adult patients admitted for the evaluation of aetiology of PE from September 2018 to July 2021 will be enrolled after informed consent. Pleural fluid and serum specimens will be collected and stored at -80°C for the laboratory analysis. The final diagnosis will be concurred with further imaging, microbiology, cytology and biopsy if needed. The results of investigated laboratory markers will be unknown to the clinicians who will make diagnosis and the clinical diagnoses will be unknown to the laboratory technicians who will determine markers. The diagnostic accuracy of investigated markers will be assessed using receiver operating characteristics (ROC) curve analysis, multivariable logistic regression model, decision curve analysis (DCA), net reclassification index (NRI) and integrated discriminatory index (IDI).

ETHICS AND DISSEMINATION

The study is approved by the Ethic Committee of the Affiliated Hospital of Inner Mongolia Medical University (NO: 2018011). The results of SIMPLE will be submitted to international scientific peer-reviewed journals or conferences in laboratory medicine or respiratory medicine, thoracic diseases.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR1800017449); Pre-results.

Computed tomography of the chest in unilateral pleural effusions: outcome of the British Thoracic Society guideline

Background

The guidelines from the British Thoracic Society (BTS) regarding the investigation of unilateral pleural effusions recommend computed tomography (CT) in exudates. We decided to investigate if clinicians follow BTS guidelines' recommendations with respect to CT in patients with unilateral pleural effusions. Secondly, to investigate the diagnostic consequences of following and not following this recommendation.

Methods

The study was a retrospective, non-randomized study including consecutive patients referred to our tertiary centers in 2013-2016 because of unilateral pleural effusion. Patients undergoing chest CT for unilateral pleural effusion of unknown cause after thoracentesis and chest X-ray were included. Patients were categorized as having pleural exudates or transudates, according to Light's criteria, if applicable. We registered use of CT, and calculated diagnostic values.

Results

In total, 323 of the 465 included patients underwent CT (69%). CT was performed in the majority of patients not having an exudate (transudates: n=40; 54%; Light's criteria not assessed: n=111; 67%). ¹⁸F-FDG positron emission tomography (PET)/CT without prior CT was performed in 32 patients with an exudate (58%). The sensitivity of a non-guideline supported CT (70%) was significantly higher compared to a guideline supported CT (47%), P value <0.045. The post-test probability of a positive guideline-supported CT [likelihood ratio (LR) positive 3.26] for a later diagnosis of thoracic malignancy increased the probability from 25% to 52%. A negative CT (LR negative 0.62) decreased the probability to 17%. For a non-guideline-supported CT the numbers were (LR positive 3.42) 53% and (LR negative 0.38) 11%, respectively.

Conclusions

Clinicians appear not to follow BTS guidelines when deciding to perform chest CT. The relevance of this deviation is supported by the superior sensitivity of CT non-guideline supported CT. Overall, CT is associated with suboptimal sensitivity and negative predictive values for the diagnosis of thoracic malignancy.

Mesothelium and Malignant Mesothelioma

The mesothelium is an epithelial structure derived from the embryonic mesoderm. It plays an important role in the development of a number of different organs, including the heart, lungs, and intestines. In this publication, we discuss aspects of the development of the mesothelium, where mesothelial structures can be found, and review molecular and cellular characteristics associated with the mesothelium. Furthermore, we discuss the involvement of the mesothelium in a number of disease conditions, in particular in the pathogenesis of mesotheliomas with an emphasis on malignant pleural mesothelioma (MPM)—a primary cancer developing in the pleural cavity.

The value of computed tomography in discriminating malignant from non-malignant causes of unresolved unilateral pleural effusions: a systematic review

The scientific background in expert-opinion papers for recommending Computed Tomography (CT) in unilateral pleural exudates is based on studies including patients with other findings than unilateral pleural effusions or selected patients undergoing thoracoscopy. Therefore, we performed a systematic review investigating the sensitivity of CT for predicting malignancy in patients with unilateral, non-transudative, pleural effusions. A search strategy was developed with the assistance of a medical information specialist at our university library. We searched PubMed/MEDLINE, EMBASE and Cochrane Library, ClinicalTrials.gov and articles citing the included studies. No date restrictions were applied (the first included paper was published in 2001 (1)), and only literature in English was included. We used the Quality Assessment of Diagnostic Accuracy Studies 2 for bias assessment. We registered the protocol at PROSPERO (CRD42018094830). Five studies were included, two prospective and three retrospective, all performed in Western Europe. No study reported diagnostic values for patients with unilateral, non-transudative pleural effusions only; one study did for unilateral pleural effusions. In the remaining studies, most patients had unilateral effusions and non-transudative effusions. Patients were primarily males and >70 years. All but one study found a high incidence of malignancy, dominated by malignant pleural mesothelioma. All studies were limited by risk of bias and applicability, predominantly regarding study population, pretests and index test. The current evidence supporting the sensitivity of CT for predicting malignancy in unilateral pleural effusions (both non-transudative and all types of effusion) is very low and did not allow meta-analysis. Standardization of patient population and CT protocol may facilitate conclusions of futures studies.

Incidence of malignancy and survival in patients with idiopathic pleuritis

Background

The long-term outcome after non-diagnostic thoracoscopy (idiopathic pleuritis) has not been investigated in nationwide studies, and the survival has never been estimated. Therefore, we decided to investigate the three-year incidence of malignancy and survival of patients with idiopathic pleuritis.

Methods

Retrospective, register-based, nationwide study of patients undergoing diagnostic video-assisted thoracoscopic surgery (VATS) thoracoscopy ≤30 days after thoracentesis, using The National Patient Registry and The Danish Cancer Registry. Idiopathic pleuritis was defined as; no diagnosis of malignancy within 31 days after VATS. Patients were followed for 36 months after VATS.

Results

In total, idiopathic pleuritis were identified in 547 out of 658 patients undergoing VATS (83%), and 29 (5%) were diagnosed with malignancy during the 3 years follow-up period after VATS. Of these, 93% were diagnosed with malignancy within the first year. Numbers-needed-to-follow-up for detecting one case of malignancy was 18 during the first year after VATS and 250 in the two subsequent years. Survival was independent on type of malignancy (MPM vs. other malignancies; P=0.13) and of time from VATS to diagnosis (≤31 days vs. 1-36 months; P=0.15). Median survival in the non-malignant group was 1,095 days.

Conclusions

Our study confirms a low incidence of malignancy in idiopathic pleuritis after VATS. Nearly all incident cases of malignancy were diagnosed within 12 months from VATS. No survival disadvantage was observed in patients with incident malignancy. Our data suggest that follow-up of idiopathic pleuritis could safely be limited to 1 year. The optimal follow-up strategy remains to be investigated.

Development and validation of a scoring system for the identification of pleural exudates of cardiac origin

BACKGROUND

Light's criteria misclassify about 30% of cardiac effusions as exudates, possibly leading to unnecessary testing. Our purpose was to derive and validate a scoring model to effectively identify these falsely categorized cardiac effusions, in the setting of natriuretic peptide lacking data.

METHODS

We retrospectively analyzed data from 3182 patients with exudative pleural effusions based on Light's criteria, of whom 276 had heart failure (derivation set). A scoring model was generated with those variables identified as independent predictors of cardiac effusions in a logistic regression analysis, and further evaluated in an independent population of 1165 patients.

RESULTS

The score consisted of age ≥75years (3 points), albumin gradient >1.2g/dL (3 points), pleural fluid lactate dehydrogenase <250U/L (2 points), bilateral effusions on chest radiograph (2 points), and protein gradient >2.5g/dL (1 point). At the best cutoff of ≥7 points, the score yielded 92% diagnostic accuracy, a likelihood ratio positive of 12.7 and a likelihood ratio negative of 0.39 for labeling cardiac effusions in the derivation sample. The respective figures in the validation sample were 87%, 6.5 and 0.33. Notably, the score had higher discriminatory properties than protein and albumin gradients in both the derivation (respective area under the curve - AUC - of 0.925, 0.825, and 0.801) and validation (respective AUC of 0.908 0.862 and 0.802; all p≤0.01) cohorts.

CONCLUSIONS

A simple scoring system can assist clinicians in accurately identifying false cardiac exudates when natriuretic peptides are not available.

Association of immunoglobulin G4 and free light chain with idiopathic pleural effusion

The cause of pleural effusion remains uncertain in approximately 15% of patients despite exhaustive evaluation. As recently described immunoglobulin (Ig)G4-related disease is a fibroinflammatory disorder that can affect various organs, including the lungs, we investigate whether idiopathic pleural effusion includes IgG4-associated etiology. Between 2000 and 2012, we collected 830 pleural fluid samples and reviewed 35 patients with pleural effusions undiagnosed after pleural biopsy at Yamaguchi-Ube Medical Center. Importantly, IgG4 immunostaining revealed infiltration of IgG4-positive plasma cells in the pleura of 12 patients (34%, IgG4⁺ group). The median effusion IgG4 level was 41 mg/dl in the IgG4⁺ group and 27 mg/dl in the IgG4^- group (P < 0·01). The light and heavy chains of effusion IgG4 antibodies of patients in the IgG4⁺ group were heterogeneous by two-dimensional electrophoresis, indicating the absence of clonality of the IgG4 antibodies. Interestingly, the κ light chains were more heterogeneous than the λ light chains. The measurement of the κ and λ free light chain (FLC) levels in the pleural fluids showed significantly different κ FLC levels (median: 28·0 versus 9·1 mg/dl, P < 0·01) and κ/λ ratios (median: 2·0 versus 1·2, P < 0·001) between the IgG4⁺ and IgG4^- groups. Furthermore, the κ/λ ratios were correlated with the IgG4⁺ /IgG⁺ plasma cell ratios in the pleura of the IgG4⁺ group. Taken together, these results demonstrate the involvement of IgG4 in certain idiopathic pleural effusions and provide insights into the diagnosis, pathogenesis and therapeutic opportunities of IgG4-associated pleural effusion.