Identifying transudates misclassified by Light's criteria

Sonography of the pleura

The CME review presented here is intended to explain the significance of pleural sonography to the interested reader and to provide information on its application. At the beginning of sonography in the 80 s of the 20th centuries, with the possible resolution of the devices at that time, the pleura could only be perceived as a white line. Due to the high impedance differences, the pleura can be delineated particularly well. With the increasing high-resolution devices of more than 10 MHz, even a normal pleura with a thickness of 0.2 mm can be assessed. This article explains the special features of the examination technique with knowledge of the pre-test probability and describes the indications for pleural sonography. Pleural sonography has a high value in emergency and intensive care medicine, preclinical, outpatient and inpatient, in the general practitioner as well as in the specialist practice of pneumologists. The special features in childhood (pediatrics) as well as in geriatrics are presented. The recognition of a pneumothorax even in difficult situations as well as the assessment of pleural effusion are explained. With the high-resolution technology, both the pleura itself and small subpleural consolidations can be assessed and used diagnostically. Both the direct and indirect sonographic signs and accompanying symptoms are described, and the concrete clinical significance of sonography is presented. The significance and criteria of conventional brightness-encoded B-scan, colour Doppler sonography (CDS) with or without spectral analysis of the Doppler signal (SDS) and contrast medium ultrasound (CEUS) are outlined. Elastography and ultrasound-guided interventions are also mentioned. A related further paper deals with the diseases of the lung parenchyma and another paper with the diseases of the thoracic wall, diaphragm and mediastinum.

Meigs Syndrome and Elevated CA-125: Case Report and Literature Review of an Unusual Presentation Mimicking Ovarian Cancer

Background and Objectives: Meigs syndrome is represented by a benign adnexal tumor, ascites, and hydrothorax. Even though the ovarian mass is often characterized by a fibroma-like origin, cancer antigen-125 (CA-125) serum levels could be elevated as in the development of ovarian cancer. Here, we present the case of a patient with Meigs syndrome and increased CA-125. Materials and Methods: We performed systematic research for articles including similar cases in PubMed, EMBASE, and Scopus in February 2023, adopting the string of idioms: "Meigs syndrome AND Cancer antigen 125", and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results: Eligible records were 25. Hydrothorax was right-sided in 10 cases over 25; left-sided in two patients over 25. Concerning ascites, two patients showed more than 6 L of ascitic fluid, whereas three patients had 6 L or less. CA-125 elevation ranged from 149 IU/mL to 3803 IU/mL. Adnexal mass histotypes were: struma ovarii (12 cases), thecomas (two cases), fibrothecomas (five cases), fibromas (five cases), and one sclerosing stromal tumor (SST). Conclusions: In postmenopausal women with elevated CA-125 serum levels and an adnexal mass suspicious for malignancy at ultrasound (US), ascites and pleural effusion, surgery, and histopathological examination are necessary. MS is a diagnostic option, with an excellent prognosis after exeresis of the mass.

Comparison of the Efficacy of Light's Criteria With Serum-Effusion Albumin Gradient and Pleural Effusion Glucose

Introduction While Light's criteria exhibit high sensitivity (98%) in detecting exudative pleural effusions, the capacity to rule out transudates is relatively limited. A previous study showed that approximately one-fifth of patients with congestive cardiac failure on diuretics also met the criteria for exudate. This study compares the diagnostic value of Light's criteria, the serum-effusion albumin gradient (SEAG) method, and pleural effusion glucose levels for accurately categorizing pleural effusion as transudate or exudate. Methodology We conducted this cross-sectional observational study in a tertiary care hospital in Ahmedabad, India. Two hundred patients with pleural effusion undergoing thoracentesis were included. Laboratory parameters measured in pleural fluid analysis included pleural fluid protein, pleural fluid lactate dehydrogenase (LDH), pleural fluid albumin, and pleural fluid glucose. Serum protein, serum LDH, and serum albumin were also collected. Mean values and standard deviations (SDs) were calculated for analysis. Results A significant difference was observed in the mean value of exudative and transudative effusions for each parameter (pleural fluid protein/serum fluid protein ratio, pleural fluid LDH/serum fluid LDH ratio, pleural fluid LDH, SEAG, and pleural fluid glucose) (P < 0.001). Light's criteria demonstrated the highest efficacy in diagnosing exudates (accuracy = 97.50%), while SEAG demonstrated the highest efficacy in diagnosing transudates (accuracy = 97.50%). Conclusion SEAG is an effective alternative diagnostic tool for identifying transudates misclassified by Light's criteria. Its use can contribute to prompt diagnosis and timely treatment of patients with pleural effusion, improving patient outcomes.

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.

Age affects the diagnostic accuracy of serum N-terminal pro-B-type natriuretic peptide for heart failure in patients with pleural effusion

BACKGROUND

Serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a well-recognized diagnostic marker for heart failure (HF) in patients with dyspnea or pleural effusion (PE). The effects of age on the diagnostic accuracy of NT-proBNP in dyspneic patients are widely known; however, whether its diagnostic accuracy is affected by age in patients with PE remains unknown. This study aimed to investigate the influence of age on the diagnostic accuracy of serum NT-proBNP for HF in patients with PE.

METHODS

Patients with PE were recruited from the BUFF (Biomarkers for patients with Undiagnosed pleural eFFusion) cohort and the SIMPLE (a Study Investigating Markers in PLeural Effusion) cohort. Serum NT-proBNP on admission and final diagnosis were extracted from the participant's medical records. The diagnostic accuracy of serum NT-proBNP was evaluated by a operating characteristic (ROC) curve analysis. The influence of age on the diagnostic accuracy of NT-proBNP was investigated through subgroup analyses.

RESULTS

One hundred and four participants were enrolled from the BUFF cohorts (HF, 32; non-HF, 72). One hundred and sixteen participants were enrolled from the SIMPLE cohort (HF, 21; non-HF, 95). The area under the ROC curve (AUCs) of NT-proBNP in the pooled cohort was 0.78 (95 %CI: 0.71 - 0.85). The AUC of NT-proBNP decreased in older patients.

CONCLUSION

Serum NT-proBNP has moderate diagnostic accuracy for HF in old patients with PE. The diagnostic accuracy of serum NT-proBNP in these patients decreases with the advancement of age.

The laboratory investigation of pleural fluids: An update based on the available evidence

Selecting appropriate laboratory tests based on available evidence is central to improve clinical effectiveness and impacting on patient outcome. Although long studied, there is no mutual agreement upon pleural fluid (PF) management in the laboratory context. Given the experienced confusion about the real contribution of laboratory investigations to guide clinical interpretation, in this update, we tried to identify useful tests for the PF analysis, aiming to unravel critical points and to define a common line in requesting modalities and practical management. We performed a careful literature review and a deepened study on available guidelines to finalize an evidence-based test selection, intended for clinicians' use to streamline PF management. The following tests depicted the basic PF profile routinely needed: (1) abbreviated Light's criteria (PF/serum total protein ratio and PF/serum lactate dehydrogenase ratio) and (2) cell count with differential analysis of haematological cells. This profile fulfils the primary goal to determine the PF nature and discriminate between exudative and transudative effusions. In specific circumstances, clinicians may consider additional tests as follows: the albumin serum to PF gradient, which reduces exudate misclassification rate by Light's criteria in patients with cardiac failure assuming diuretics; PF triglycerides, in differentiating chylothorax from pseudochylothorax; PF glucose, for identification of parapneumonic effusions and other causes of effusion, such as rheumatoid arthritis and malignancy; PF pH, in suspected infectious pleuritis and to give indications for pleural drainage; and PF adenosine deaminase, for a rapid detection of tuberculous effusion.

Pleural fluid biochemical analysis: the past, present and future

Identifying the cause of pleural effusion is challenging for pulmonologists. Imaging, biopsy, microbiology and biochemical analyses are routinely used for diagnosing pleural effusion. Among these diagnostic tools, biochemical analyses are promising because they have the advantages of low cost, minimal invasiveness, observer independence and short turn-around time. Here, we reviewed the past, present and future of pleural fluid biochemical analysis. We reviewed the history of Light’s criteria and its modifications and the current status of biomarkers for heart failure, malignant pleural effusion, tuberculosis pleural effusion and parapneumonic pleural effusion. In addition, we anticipate the future of pleural fluid biochemical analysis, including the utility of machine learning, molecular diagnosis and high-throughput technologies. Clinical Chemistry and Laboratory Medicine (CCLM) should address the topic of pleural fluid biochemical analysis in the future to promote specific knowledge in the laboratory professional community.

Application of Contrast-Enhanced Ultrasound to Detect Hepatic Hydrothorax in Patients with Liver Cirrhosis

PURPOSE

 Hepatic hydrothorax (HH) is defined as transudate in the pleural cavity in patients with decompensated liver cirrhosis (DC) without concomitant cardiopulmonary or pleural disease. It is associated with high short-term mortality. HH can evolve via translocation through diaphragmatic gaps. The aim of this study was to evaluate the feasibility and safety of injecting ultrasound contrast medium into the peritoneal cavity to detect HH.

MATERIALS AND METHODS

 This study included patients with concomitant ascites and pleural effusion who were admitted to our hospital between March 2009 and February 2019. A peritoneal catheter was inserted and ultrasound contrast medium was injected into the peritoneal cavity. In parallel, the peritoneal and pleural cavities were monitored for up to 10 minutes.

RESULTS

 Overall, 43 patients were included. The median age was 60 years and the majority of patients were male (n = 32, 74 %). Most patients presented with right-sided pleural effusion (n = 32, 74 %), 3 (7 %) patients with left-sided and 8 (19 %) patients had bilateral pleural effusion. In 12 (28 %) patients ascites puncture was not safe due to low volume ascites. Thus, the procedure could be performed in 31 (72 %) patients. No adverse events occurred. In 16 of 31 (52 %) patients we could visualize a trans-diaphragmic flow of microbubbles. The median time until transition was 120 seconds.

CONCLUSION

 Our clinical real-world experience supports the safety and feasibility of intraperitoneal ultrasound contrast medium application to detect HH in patients with DC, as a non-radioactive real-time visualization of HH. Our study comprises the largest cohort and longest experience using this method to date.

Diagnosis of parapneumonic pleural effusion with serum and pleural fluid Activin A

OBJECTIVE

The aim is to evaluate the diagnostic value of Activin A levels in serum and pleural fluid on Parapneumonic Pleural Effusion (PPE).

METHODS

The authors collected serum and pleural fluid from 86 PPE and 37 Non-PPE (NPPE) patients. Including Activin A, levels of biomarkers such as Lactate Dehydrogenase (LDH), Procalcitonin (PCT), and C-Reactive Protein (CRP) were measured. All factors were calculated for association with days after admission. The diagnostic potential of biomarkers on PPE was considered by Receiver Operating Characteristic (ROC) curve analysis.

RESULTS

Levels of Activin A in serum and pleural fluid of PPE patients were significantly higher than those of the NPPE patients. Moreover, concentrations of Activin A in pleural fluid showed a more obvious relevant days after admission. ROC curve analysis found that Activin A in pleural fluid had AUCs of 0.899 with 93% sensitivity and 84% specificity for PPE diagnosis.

CONCLUSION

Activin A in pleural fluid correlated with disease severity could act to diagnose PPE.

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!

A Predictive Model for the Identification of Cardiac Effusions Misclassified by Light's Criteria

OBJECTIVES

The application of Light's criteria misidentifies approximately 30% of transudates as exudates, particularly in patients on diuretics with cardiac effusions. The purpose of this study was to establish a predictive model to effectively identify cardiac effusions misclassified by Light's criteria.

METHODS

We retrospectively studied 675 consecutive patients with pleural effusion diagnosed by Light's criteria as exudates, of which 43 were heart failure patients. A multivariate logistic model was developed to predict cardiac effusions. The performance of the predictive model was assessed by receiver operating characteristic (ROC) curves, as well as by examining the calibration.

RESULTS

It was found that protein gradient of >23 g/L, pleural fluid lactate dehydrogenase (PF-LDH) levels, ratio of pleural fluid LDH to serum LDH level (P/S LDH), pleural fluid adenosine deaminase (PF-ADA) levels, and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels had a significant impact on the identification of cardiac effusions, and those were simultaneously analyzed by multivariate regression analysis. The area under the curve (AUC) value of the model was 0.953. The model also had higher discriminatory properties than protein gradients (AUC, 0.760) and NT-pro-BNP (AUC, 0.906), all at a P value of <.01.

CONCLUSION

In cases of suspected cardiac effusion, or where clinicians cannot identify the cause of an exudative effusion, this model may assist in the correct identification of exudative effusions as cardiac effusions.

Laboratory testing of extravascular body fluids: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Part I - Serous fluids

Extravascular body fluids (EBF) analysis can provide useful information in the differential diagnosis of conditions that caused their accumulation. Their unique nature and particular requirements accompanying EBF analysis need to be recognized in order to minimize possible negative implications on patient safety. This recommendation was prepared by the members of the Working group for extravascular body fluid samples (WG EBFS). It is designed to address the total testing process and clinical significance of tests used in EBF analysis. The recommendation begins with a chapter addressing validation of methods used in EBF analysis, and continues with specific recommendations for serous fluids analysis. It is organized in sections referring to the preanalytical, analytical and postanalytical phase with specific recommendations presented in boxes. Its main goal is to assist in the attainment of national harmonization of serous fluid analysis and ultimately improve patient safety and healthcare outcomes. This recommendation is intended to all laboratory professionals performing EBF analysis and healthcare professionals involved in EBF collection and processing. Cytological and microbiological evaluations of EBF are beyond the scope of this document.

Malignant Pleural Effusion and Its Current Management: A Review

Malignant pleural effusion (MPE) is an exudative effusion with malignant cells. MPE is a common symptom and accompanying manifestation of metastatic disease. It affects up to 15% of all patients with cancer and is the most common in lung, breast cancer, lymphoma, gynecological malignancies and malignant mesothelioma. In the last year, many studies were performed focusing on the pathophysiological mechanisms of MPE. With the advancement in molecular techniques, the importance of tumor-host cell interactions is becoming more apparent. Additionally, the process of pathogenesis is greatly affected by activating mutations of EGFR, KRAS, PIK3CA, BRAF, MET, EML4/ALK and RET, which correlate with an increased incidence of MPE. Considering all these changes, the authors aim to present a literature review of the newest findings, review of the guidelines and pathophysiological novelties in this field. Review of the just recently, after seven years published, practice guidelines, as well as analysis of more than 70 articles from the Pubmed, Medline databases that were almost exclusively published in indexed journals in the last few years, have relevance and contribute to the better understanding of the presented topic. MPE still presents a severe medical condition in patients with advanced malignancy. Recent findings in the field of pathophysiological mechanisms of MPE emphasize the role of molecular factors and mutations in the dynamics of the disease and its prognosis. Treatment guidelines offer a patient-centric approach with the use of new scoring systems, an out of hospital approach and ultrasound. The current guidelines address multiple areas of interest bring novelties in the form of validated prediction tools and can, based on evidence, improve patient outcomes. However, the role of biomarkers in a clinical setting, possible new treatment modalities and certain specific situations still present a challenge for new research.

Significance of congestive heart failure as a cause of pleural effusion: Pilot data from a large multidisciplinary teaching hospital

BACKGROUND

Epidemiological data on the causes of pleural effusion (PE) are scarce. Data on the local prevalence of various causes of PE may play a crucial role in the management strategy of patients with PE. The aim of the study was to investigate the causes of PE and to assess 30-day mortality rate in unselected adult patients treated in a large, multidisciplinary hospital.

METHODS

Retrospective analysis of medical records, including chest radiographs, of 2835 consecutive patients admitted to the hospital was performed. Radiograhic signs of PE were found in 195 of 1936 patients in whom chest radigraphs were available. These patients formed the study group.

RESULTS

The leading causes of PE were as follows: congestive heart failure (CHF; 37.4%), pneumonia (19.5%), malignancy (15.4%), liver cirrhosis (4.2%) and pulmonary embolism. The cause of PE in 6.7% patients was not established. There was a significant predominance of small volume PE as compared to a moderate or large volume PEs (153, 28 and 14 patients, respectively). Almost 80% of patients with CHF presented with small volume PE, while almost 50% of patients with malignant PE demonstrated moderate or large volume PE. Thirty-day mortality rate ranged from 0% for tuberculous pleurisy to 40% for malignant PE (MPE).

CONCLUSIONS

Pleural effusion was found in 10.1% of patients treated in a large multidisciplinary hospital. CHF was the leading cause of PE. Although 30-day mortality in patients with CHF was rela-tively high, it was lower than that in parapneumonic PE and MPE.

Hepatic Hydrothorax

Hepatic hydrothorax (HH) is a pleural effusion that develops in a patient with cirrhosis and portal hypertension in the absence of cardiopulmonary disease. Although the development of HH remains incompletely understood, the most acceptable explanation is that the pleural effusion is a result of a direct passage of ascitic fluid into the pleural cavity through a defect in the diaphragm due to the raised abdominal pressure and the negative pressure within the pleural space. Patients with HH can be asymptomatic or present with pulmonary symptoms such as shortness of breath, cough, hypoxemia, or respiratory failure associated with large pleural effusions. The diagnosis is established clinically by finding a serous transudate after exclusion of cardiopulmonary disease and is confirmed by radionuclide imaging demonstrating communication between the peritoneal and pleural spaces when necessary. Spontaneous bacterial empyema is serious complication of HH, which manifest by increased pleural fluid neutrophils or a positive bacterial culture and will require antibiotic therapy. The mainstay of therapy of HH is sodium restriction and administration of diuretics. When medical therapy fails, the only definitive treatment is liver transplantation. Therapeutic thoracentesis, indwelling tunneled pleural catheters, transjugular intrahepatic portosystemic shunt and thoracoscopic repair of diaphragmatic defects with pleural sclerosis can provide symptomatic relief, but the morbidity and mortality is high in these extremely ill patients.

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.

Biomarkers in the diagnosis of pleural diseases: a 2018 update

The use of biomarkers on pleural fluid (PF) specimens may assist the decision-making process and enhance clinical diagnostic pathways. Three paradigmatic examples are heart failure, tuberculosis and, particularly, malignancy. An elevated PF concentration of the amino-terminal fragment of probrain natriuretic peptide (>1500 pg/ml) is a hallmark of acute decompensated heart failure. Adenosine deaminase, interferon-γ and interleukin-27 are three valuable biomarkers for diagnosing tuberculous pleurisy, yet only the first has been firmly established in clinical practice. Diagnostic PF biomarkers for malignancy can be classified as soluble-protein based, immunocytochemical and nucleic-acid based. Soluble markers (e.g. carcinoembryonic antigen (CEA), carbohydrate antigen 15-3, mesothelin) are only indicative of cancer, but not confirmatory. Immunocytochemical studies on PF cell blocks allow: (a) to distinguish mesothelioma from reactive mesothelial proliferations (e.g. loss of BAP1 nuclear expression, complemented by the demonstration of p16 deletion using fluorescence in situ hybridization, indicate mesothelioma); (b) to separate mesothelioma from adenocarcinoma (e.g. calretinin, CK 5/6, WT-1 and D2-40 are markers of mesothelioma, whereas CEA, EPCAM, TTF-1, napsin A, and claudin 4 are markers of carcinoma); and (c) to reveal tumor origin in pleural metastases of an unknown primary site (e.g. TTF-1 and napsin A for lung adenocarcinoma, p40 for squamous lung cancer, GATA3 and mammaglobin for breast cancer, or synaptophysin and chromogranin A for neuroendocrine tumors). Finally, PF may provide an adequate sample for analysis of molecular markers to guide patients with non-small cell lung cancer to appropriate targeted therapies. Molecular testing must include, at least, mutations of epidermal growth-factor receptor and BRAF V600E, translocations of rat osteosarcoma and anaplastic lymphoma kinase, and expression of programmed death ligand 1.

Hepatic hydrothorax: An update and review of the literature

This review considers the modern concepts of pathogenesis, diagnostic methods, and treatment principles of hepatic hydrothorax (HH). HH is the excessive (> 500 mL) accumulation of transudate in the pleural cavity in patients with decompensated liver cirrhosis but without cardiopulmonary and pleural diseases. It causes respiratory failure which aggravates the clinical course of liver cirrhosis, and the emergence of spontaneous bacterial pleural empyema may be the cause of death. The information was collected from the PubMed database, the Google Scholar retrieval system, the Cochrane reviews, and the reference lists from relevant publications for 1994-2016 using the keywords: “liver cirrhosis”, “portal hypertension”, “hepatic hydrothorax”, “pathogenesis”, “diagnostics”, and “treatment”. To limit the scope of this review, only articles dealing with uncomplicated hydrothorax in patients with liver cirrhosis were included. The analysis of the data showed that despite the progress of modern hepatology, the presence of HH is associated with poor prognosis and high mortality. Most patients suffering from it are candidates for orthotopic liver transplantation. In routine clinical practice, stratification of the risk for an adverse outcome and the subsequent determination of individual therapeutic strategies may be the keys to the successful management of the patient’s condition. The development of pathogenetic pharmacotherapy and optimization of minimally invasive treatment will improve the quality of life and increase the survival rate among patients with HH.

Proteomic characterization of pleural effusion, a specific host niche of Mycoplasma mycoides subsp. mycoides from cattle with contagious bovine pleuropneumonia (CBPP)

Mycoplasma mycoides subsp. mycoides (Mmm) is the causative agent of contagious bovine pleuropneumonia (CBPP), a severe pleuropneumonia in cattle. The abnormal accumulation of pleural fluid, called pleural effusion (PE), is one of the characteristics of this disease. We performed a proteomic analysis of seven PE samples from experimentally infected cattle and characterized their composition with respect to bovine and Mmm proteins. We detected a total of 963 different bovine proteins. Further analysis indicated a strong enrichment of proteins involved in antigen processing, platelet activation and degranulation and apoptosis and an increased abundance of acute phase proteins.With regard to the pathogen, up to 108 viable mycoplasma cells per ml were detected in the PE supernatant. The proteomic analysis revealed 350 mycoplasma proteins, including proteins involved in virulence-associated processes like hydrogen peroxide (H2O2) production and capsule synthesis. The bovine proteins detected will aid to characterize the inflammasome during an acute pleuropneumonia in cattle and the identified mycoplasma proteins will serve as baseline data to be compared with in vitro studies to improve our understanding of pathogenicity mechanisms. Based on our results, we named the pleural effusion an “in vivo niche” of Mmm during the acute phase of CBPP. Biological significance: This is the first study on bovine pleural effusions derived from an infectious disease and the first approach to characterize the proteome of Mycoplasma mycoides in vivo. This study revealed a high number of viable Mmm cells in the pleural effusion. The bovine pleural effusion proteome during Mmm infection is qualitatively similar to plasma, but differs with respect to high abundance of acute phase proteins. On the other hand,Mmm in its natural host produces proteins involved in capsule synthesis, H2O2 production and induction of inflammatory response, supporting previous knowledge on mechanisms underlying the survival and virulence of this pathogen while inside the natural host. This knowledge forms a profound basis for testing the identified protein candidates for diagnostics or vaccines.

The diagnosis of pleural effusions

Pleural effusions arise from a variety of systemic, inflammatory, infectious and malignant conditions. Their precise etiological diagnosis depends on a combination of medical history, physical examination, imaging tests and pertinent pleural fluid analyses; including specific biomarkers (e.g., natriuretic peptides for heart failure, adenosine deaminase for tuberculosis, or mesothelin for mesothelioma). Invasive procedures, such as pleuroscopic biopsies, may be required for persistently symptomatic effusions which remain undiagnosed after the analysis of one or more pleural fluid samples. However, whenever parietal pleural nodularity or thickening exist, image-guided biopsies should first be attempted. This review addresses the current diagnostic approach to pleural effusions secondary to heart failure, pneumonia, cancer, tuberculosis and other less frequent conditions.

Adenosine deaminase activity in pleural effusions of lymphoma patients

BACKGROUND AND AIM

The purpose of this study was to assess the relationship of pleural adenosine deaminase (P-ADA) and non-Hodgkin's lymphoma (NHL).

DESIGN AND METHODS

We retrospectively analysed 63 NHL patients with pleural effusions who accepted a diagnostic thoracentesis and who had P-ADA available at the China Medical University Hospital (Taichung, Taiwan) between January 2003 and April 2012.

RESULTS

There were 46 exudates [40 malignant pleural effusions (MPE), 5 complicated para-pneumonic effusions and 1 undiagnosed effusion] and 17 transudates. The P-ADA activity was significantly different between the two groups (P < 0.005). Among 40 MPE cases, 29 were due to B-cell and 11 due to T-cell NHL. There was no pleural transudative effusion with P-ADA value higher than 26 U/l in our study, but simultaneously 48% (22/46) of exudative pleural effusions showed a P-ADA value under that cut-off point. The P-ADA level reached the diagnostic cut-off for tuberculosis (40 IU/l) in 11 cases of MPE (11/40 = 27.5%): 9 B-cell NHL (9/29 = 31%) and 2 T-cell NHL (2/11 = 18%). The median levels (25th, 75th percentiles) of P-ADA were 28 IU/l (14-50) in the MPE of B-cell NHL and 26 IU/l (14-28) in the T-cell NHL (P = 0.693).

CONCLUSIONS

The use of P-ADA in NHL effusion could aid the separation of transudates from exudates. Around one-quarter MPE of NHL had abnormal P-ADA ( > 40 IU/l). There was no difference in the P-ADA activity in T-cell and B-cell NHL.

Diagnostic value of suPAR in differentiating noncardiac pleural effusions from cardiac pleural effusions

INTRODUCTION

Soluble urokinase plasminogen activator receptor (suPAR) is a newly discovered inflammatory biomarker. suPAR has not been previously studied in differentiating noncardiac pleural effusion (PF) from cardiac PF. The aim of our study was to assess the diagnostic value of suPAR in PF.

METHODS

The concentration of PF-suPAR was measured by a commercialized enzyme-linked immunosorbent assay in a prospective cohort of 74 patients with PF, 18 patients with PF due to cardiac failure (CF) and 56 patients with noncardiac PF. The area under the curve quantified the overall diagnostic accuracy of the tests.

RESULTS

The median pleural fluid suPAR level was found as 23 (5.4-102.8) ng/mL. The median PF-suPAR level in CF was significantly lower than that of noncardiac effusions [11.8 (5.4-28.9) ng/mL vs 26.7 (8.2-102.8) ng/mL, respectively, P < 0.001]. The area under the receiver operating characteristic curve was 0.878 (95% confidence interval: 0795-0.962, P < 0.001) for noncardiac pleural fluid suPAR. The sensitivity, specificity and positive predictive value of PF-suPAR for noncardiac effusions at the cutoff level of ≥17.6 n/mL was 88%, 83% and 94%, respectively. The suPAR level in PF was found to correlate with all of the biochemical parameters of PF.

CONCLUSIONS

suPAR is a potential new marker for the discrimination between cardiac and noncardiac PF.

Effectiveness and safety of diagnostic flexi-rigid thoracoscopy in differentiating exudative pleural effusion of unknown etiology: a retrospective study of 215 patients

BACKGROUND

The aim of this study was to evaluate the effectiveness and safety of diagnostic flexi-rigid thoracoscopy in differentiating exudative pleural effusion of unknown etiology.

METHODS

A total of 215 patients with undiagnosed exudative pleural effusion were consecutively recruited between January 2011 and February 2013. Thoracoscopy was carried out under local anesthesia, and multisite pleural biopsies were performed using a flexi-rigid thoracoscope. The tolerance of the patients, surgical complications and postoperative pathological diagnosis rate were used to evaluate the effectiveness and safety of the thoracoscopy procedures.

RESULTS

All patients, Karnofsky performance status (KPS) >70, could tolerate both the thoracoscopic surgery and pleural biopsy; there were no severe complications. Thoracoscopic findings included pleural hyperaemia, fibrinous adhesion, nodular bulge and fester. The pathological biopsy confirmed diagnoses of malignant tumor (97 cases), tuberculous pleuritis (91 cases), tuberculous empyema (one case), pulmonary schistosomiasis (one case) and unknown etiology (25 cases). The total diagnosis rate was 88.4%. Subcutaneous emphysema occurred in ten cases and fever in six cases, all of which recovered completely with conservative treatment.

CONCLUSIONS

Flexi-rigid thoracoscopy had a high diagnosis rate, differentiating exudative pleural effusion of unknown etiology with satisfactory effectiveness and safety. There was high degree of relationship between thoracoscopic appearance and primary disease or tumor classification.

Can cholesterol be used to distinguish pleural exudates from transudates? evidence from a bivariate meta-analysis

Background

Many studies have investigated whether pleural cholesterol levels can aid in diagnosis of pleural exudates, and the results have varied considerably. To gain a more reliable answer to this question, we meta-analyzed the literature on using pleural cholesterol or the ratio of cholesterol in pleural fluid to cholesterol in serum (P/S cholesterol ratio) as diagnostic tests to help identify pleural exudates.

Methods

Literature databases were systematically searched for studies examining accuracy of pleural cholesterol or P/S cholesterol ratios for diagnosing pleural exudates. Data on sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and diagnostic odds ratio (DOR) were pooled using bivariate-effects models. Summary receiver operating characteristic (SROC) curves and area under the curve (AUC) were used to summarize overall test performance.

Results

Our meta-analysis included up to 20 studies involving 3,496 subjects. Summary estimates for pleural cholesterol in the diagnosis of pleural exudates were as follows: sensitivity, 0.88 (95%CI 0.84 to 0.92); specificity, 0.96 (95% CI 0.92 to 0.98); PLR, 20.31 (95% CI 11.21 to 36.78); NLR, 0.12 (95% CI 0.09 to 0.17); DOR, 167.06 (95% CI 76.79 to 363.95); and AUC 0.97 (95% CI 0.95 to 0.98). The corresponding summary performance estimates for using the P/S cholesterol ratio were as follows: sensitivity, 0.94 (95% CI 0.92 to 0.96); specificity, 0.87 (95% CI 0.83 to 0.91); PLR 7.46 (95% CI, 5.47 to 10.19); NLR, 0.07 (95% CI 0.05 to 0.10); DOR, 107.74 (95% CI 60.91 to 190.60); and AUC 0.97 (95% CI 0.95 to 0.98).

Conclusions

Both pleural cholesterol level and the P/S cholesterol ratio are helpful for the diagnosis of pleural exudates. Nevertheless, the results of pleural cholesterol assays should be interpreted in parallel with the results of traditional tests and clinical information.

Etiology of pleural effusions: analysis of more than 3,000 consecutive thoracenteses

OBJECTIVE

To investigate the etiology of pleural effusions (PE) in adults and the accuracy of pleural fluid (PF) cytology and cultures in malignant and infectious PE, respectively.

PATIENTS AND METHODS

Retrospective analysis of all consecutive patients with PE undergoing diagnostic thoracentesis during the last 19 years in a university hospital.

RESULTS

The leading causes of PE among the 3,077 patients were: cancer (27%), heart failure (21%), pneumonia (19%), tuberculosis (9%), abdominal surgery (4%), pericardial diseases (4%) and cirrhosis (3%). Tuberculosis was the most common etiology in patients <34 years of age (52%), whereas heart failure predominated in octogenarians (45%). The most common primary tumors in malignant PE were lung (37%) and breast (16%). The overall accuracy of PF cytology was 59%, although it was significantly lower in mesotheliomas (27%) and squamous cell lung cancer (25%). In infectious PE, only 30% of cultures yielded positive results, a percentage which increased two-fold (66%) in purulent fluids (empyemas). Viridans streptococci were the most commonly isolated pathogens (25.5%). The sensitivity of solid media cultures of PF for Mycobacterium tuberculosis was low (18.5%).

CONCLUSIONS

Three-quarters of patients with PE in whom a diagnostic thoracentesis was indicated had cancer, heart failure, pneumonia or tuberculosis. PF cytology and cultures give false negative results in a significant number of cases.