Comparison of polymorphonuclear- and lymphocyte-rich tuberculous pleural effusions

A retrospective study of extrapulmonary tuberculosis in the Khuzestan province of southwest Iran between 2002 and 2023

BACKGROUND

Worldwide, tuberculosis (TB) is among the most common causes of death. To our knowledge, there has been no study showing the prevalence of EPTB in Khuzestan province. Therefore, the objective of this research was to investigate the prevalence of EPTB in patients with or without pulmonary TB in different cities of Khuzestan province from 2002 to 2023. Additionally, the correlation between patient's gender, and age groups with the disease was also investigated.

METHODS

In this retrospective study, the existing records in Tuberculosis Regional Reference Laboratory of Khuzestan province related to patients were used. The research was carried out by investigating the archive information in 19 years (from 1st January 2002 to December 30, 2023). All confirmed cases of EPTB and simultaneous EPTB and PTB, based on laboratory results and medical examination were included in the study. Patients with incomplete information and military TB were excluded from the study. Information collected from patients includes age, gender, involved organ, place of residence, and year of disease.

RESULTS

A total of 12,900 EPTB-related medical records were extracted from Tuberculosis Regional Reference Laboratories in southwest Iran, Ahvaz. After excluding records, 12,836 clinically diagnosed or laboratory-confirmed tuberculosis patients were included in this study, including 5991 patients with simultaneous PTB and EPTB, and 6845 patients with EPTB only. The mean age of male EPTB patients was 37.5 years (SD ± 14.6), while the mean age of male patients with simultaneous PTB and EPTB was 45.8 years (SD ± 15.3). The mean age of female patients with EPTB only, and with simultaneous PTB and EPTB was 31.2 years (SD ± 12.6), and 31.5 years respectively.

DISCUSSION

tuberculosis is a systemic disease with different clinical manifestations. This study described different epidemiologic patterns of concurrent EPTB. The proportion of different types of EPTB was simultaneously determined for a group of hospitalized patients and shown to be different with gender and age. This study will likely increase clinicians' awareness of the disease and help them better address diagnostic challenges and improve treatment outcomes for patients with EPTB.

Validation of a diagnostic flowchart for tuberculous pleurisy in pleural fluid with high levels of adenosine deaminase

INTRODUCTION

Adenosine deaminase (ADA) in pleural fluid is a useful marker for diagnosing tuberculous pleurisy. However, recent studies have reported a lower specificity of pleural fluid ADA levels. We previously developed a diagnostic flowchart for patients with pleural fluid ADA ≥40 U/L, incorporating variables such as pleural fluid lactate dehydrogenase <825 U/L, predominant pleural fluid neutrophils or cell degeneration, and a pleural fluid ADA/total protein ratio <14. This flowchart was effective in distinguishing between tuberculous pleurisy and other diseases. Here, we conducted a validation analysis of this flowchart.

MATERIALS AND METHODS

We retrospectively collected data from 458 patients with pleural fluid ADA concentrations ≥40 U/L across eight institutions from January 2019 to December 2023. The diagnostic accuracy rate, sensitivity, and specificity of the diagnostic flowchart were analysed and compared to those in the original study.

RESULTS

Eighty-seven patients were diagnosed with tuberculous pleurisy, and 371 patients were diagnosed with other diseases. The diagnostic accuracy, sensitivity, and specificity for diagnosing tuberculous pleurisy were 77.7%, 86.2%, and 75.7%, respectively. Compared with that in the original study, the rate of tuberculous pleurisy was lower (19.0% vs. 44.5%, p < 0.001), but the diagnostic accuracy rates were not significantly different (p = 0.253). On the basis of the findings from this validation study, we have revised the flowchart to enhance its utility.

CONCLUSION

The diagnostic flowchart exhibited high diagnostic accuracy in this validation study, comparable to that in the original study. This validation confirms the effectiveness of the flowchart, even in settings with a low incidence of tuberculosis.

Diagnostic value of effusion adenosine deaminase, γ-interferon release assay and effusion lactatedehy drogenase/effusion adenosine deaminase for tuberculous pleural effusion in patients aged 60 years and above

Background

China is experiencing rapid growth in its population of older adults, which may lead to increased susceptibility to tuberculous pleural effusion (TPE) due to age-related changes in the immune system. This study aimed to investigate the diagnostic potential of multiple biomarkers in individuals aged 60 years and above with pleural effusion.

Methods

A total of 519 adult patients from Ningbo First Hospital were included in the study, with 7 biomarkers and their ratios in serum and pleural effusion analyzed using logistic regression analysis. Effusion Adenosine Deaminase(ADA), γ-Interferon Release Assay(IGRA), and Effusion lactatedehy drogenase(LDH)/Effusion ADA were identified as valuable parameters for differentiating TPE from non-TPE, particularly in individuals aged 60 years and older.

Results

Effusion ADA, IGRA, and Effusion LDH/Effusion ADA were identified as valuable parameters for the differential diagnosis of TPE from non-TPE, showing good diagnostic performance in individuals aged 60 years and older. The combined diagnosis of these three indexes achieved the highest diagnostic accuracy for TPE in this age group, with an AUC of 0.925, sensitivity of 85.23%, and specificity of 89.57%.

Conclusions

Overall, the study highlights the importance of using multiple indicators for a combined diagnosis to improve diagnostic efficacy in detecting tuberculous pleurisy in older individuals as for young patients.

Tuberculous pleuritis: clinical presentations and diagnostic challenges

PURPOSE OF REVIEW

Tuberculous pleuritis (TBP) is one of the most common types of extrapulmonary tuberculosis. We highlight the latest epidemiology of TBP, the heterogeneity of its presentation and the performance of different diagnostic strategies.

RECENT FINDINGS

There are differential trends in the incidences of TBP worldwide. Its incidence increased in China but decreased in the United States in the past decade. The presentation of TBP is heterogeneous regarding clinical symptoms, radiological findings and pleural fluid analysis results. Conventional microbiological tests have low sensitivities to diagnose TBP. Recent research focused on various diagnostic tools with better yield. The sensitivity of nucleic acid amplification tests (NAAT) in pleural fluid, including the latest generation of PCR and sequencing-based techniques for detecting tuberculosis, remains suboptimal. Various pleural fluid biomarkers have been explored, but there is a lack of consensus on their clinical utility and cutoff levels.

SUMMARY

The heterogeneity of clinical presentation poses obstacles to diagnosing TBP. Further development of diagnostic tools, including more robust NAAT and biomarkers with additional validation, is needed before incorporation into routine clinical practice.

Myeloid-derived suppressor cells in pleural effusion as a diagnostic marker for early discrimination of pulmonary tuberculosis from pneumonia

Introduction

Tuberculous pleural effusion (TPE) stands as one of the primary forms of extrapulmonary tuberculosis (TB) and frequently manifests in regions with a high prevalence of TB, consequently being a notable cause of pleural effusion in such areas. However, the differentiation between TPE and parapneumonic pleural effusion (PPE) presents diagnostic complexities. This study aimed to evaluate the potential of myeloid-derived suppressor cells (MDSCs) in the pleural fluid as a potential diagnostic marker for distinguishing between TPE and PPE.

Methods

Adult patients, aged 18 years or older, who presented to the emergency room of a tertiary referral hospital and received a first-time diagnosis of pleural effusion, were prospectively enrolled in the study. Various immune cell populations, including T cells, B cells, natural killer (NK) cells, and MDSCs, were analyzed in both pleural fluid and peripheral blood samples.

Results

In pleural fluid, the frequency of lymphocytes, including T, B, and NK cells, was notably higher in TPE compared to PPE. Conversely, the frequency of polymorphonuclear (PMN)-MDSCs was significantly higher in PPE. Notably, compared to traditional markers such as the neutrophil-to-lymphocyte ratio and adenosine deaminase level, the frequency of PMN-MDSCs emerged as a more effective discriminator between PPE and TPE. PMN-MDSCs demonstrated superior positive and negative predictive values and exhibited a higher area under the curve in the receiver operating characteristic curve analysis. PMN-MDSCs in pleural effusion increased the levels of reactive oxygen species and suppressed the production of interferon-gamma from T cells following nonspecific stimulation. These findings suggest that MDSC-mediated immune suppression may contribute to the pathology of both TPE and PPE.

Discussion

The frequency of PMN-MDSCs in pleural fluid is a clinically useful indicator for distinguishing between TPE and PPE.

Diagnostic and comparative performance for the prediction of tuberculous pleural effusion using machine learning algorithms

OBJECTIVE

Early diagnosis and differential diagnosis of tuberculous pleural effusion (TPE) remains challenging and is critical to the patients' prognosis. The present study aimed to develop nine machine learning (ML) algorithms for early diagnosis of TPE and compare their performance.

METHODS

A total of 1435 untreated patients with pleural effusions (PEs) were retrospectively included and divided into the training set (80%) and the test set (20%). The demographic and laboratory variables were collected, preprocessed, and analyzed to select features, which were fed into nine ML algorithms to develop an optimal diagnostic model for TPE. The proposed model was validated by an independently external data. The decision curve analysis (DCA) and the SHapley Additive exPlanations (SHAP) were also applied.

RESULTS

Support vector machine (SVM) was the best model in discriminating TPE from non-TPE, with a balanced accuracy of 87.7%, precision of 85.3%, area under the curve (AUC) of 0.914, sensitivity of 94.7%, specificity of 80.7%, and F1-score of 86.0% among the nine ML algorithms. The excellent diagnostic performance was also validated by the external data (a balanced accuracy of 87.7%, precision of 85.2%, and AUC of 0.898). Neural network (NN) and K-nearest neighbor (KNN) had better net benefits in clinical usefulness. Besides, PE adenosine deaminase (ADA), PE carcinoembryonic antigen (CEA), and serum CYFRA21-1 were identified as the top three important features for diagnosing TPE.

CONCLUSIONS

This study developed and validated a SVM model for the early diagnosis of TPE, which might help clinicians provide better diagnosis and treatment for TPE patients.

Features which discriminate between tuberculosis and haematologic malignancy as the cause of pleural effusions with high adenosine deaminase

BACKGROUND

Adenosine deaminase (ADA) is a useful biomarker for the diagnosis of tuberculous pleurisy (TBP). However, pleural effusions with high ADA can also be caused by other diseases, particularly hematologic malignant pleural effusion (hMPE). This study aimed to investigate the features that could differentiate TBP and hMPE in patients with pleural effusion ADA ≥ 40 IU/L.

METHODS

This was a retrospective observational study of patients with pleural effusion ADA ≥ 40 IU/L, conducted at a Korean tertiary referral hospital with an intermediate tuberculosis burden between January 2010 and December 2017. Multivariable logistic regression analyses were performed to investigate the features associated with TBP and hMPE, respectively.

RESULTS

Among 1134 patients with ADA ≥ 40 IU/L, 375 (33.1%) and 85 (7.5%) were diagnosed with TBP and hMPE, respectively. TBP and hMPE accounted for 59% (257/433) and 6% (27/433) in patients with ADA between 70 and 150 IU/L, respectively. However, in patients with ADA ≥ 150 IU/L, they accounted for 7% (9/123) and 19% (23/123), respectively. When ADA between 40 and 70 IU/L was the reference category, ADA between 70 and 150 IU/L was independently associated with TBP (adjusted odds ratio [aOR], 3.11; 95% confidence interval [CI], 1.95-4.95; P < 0.001). ADA ≥ 150 IU/L was negatively associated with TBP (aOR, 0.35; 95% CI, 0.14-0.90; P = 0.029) and positively associated with hMPE (aOR, 13.21; 95% CI, 5.67-30.79; P < 0.001). In addition, TBP was independently associated with lymphocytes ≥ 35% and a lactate dehydrogenase (LD)/ADA ratio < 18 in pleural effusion. hMPE was independently associated with pleural polymorphonuclear neutrophils < 50%, thrombocytopenia, and higher serum LD. A combination of lymphocytes ≥ 35%, LD/ADA < 18, and ADA < 150 IU/L demonstrated a sensitivity of 0.824 and specificity of 0.937 for predicting TBP.

CONCLUSION

In patients with very high levels of pleural effusion ADA, hMPE should be considered. Several features in pleural effusion and serum may help to more effectively differentiate TBP from hMPE.

The tuberculous pleural effusion

Pleural tuberculosis (TB) is a common entity with similar epidemiological characteristics to pulmonary TB. It represents a spectrum of disease that can variably self-resolve or progress to TB empyema with severe sequelae such as chronic fibrothorax or empyema necessitans. Coexistence of and progression to pulmonary TB is high. Diagnosis is challenging, as pleural TB is paucibacillary in most cases, but every effort should be made to obtain microbiological diagnosis, especially where drug resistance is suspected. Much attention has been focussed on adjunctive investigations to support diagnosis, but clinicians must be aware that apparent diagnostic accuracy is affected both by the underlying TB prevalence in the population, and by the diagnostic standard against which the specified investigation is being evaluated. Pharmacological treatment of pleural TB is similar to that of pulmonary TB, but penetration of the pleural space may be suboptimal in complicated effusions. Evidence for routine drainage is limited, but evacuation of the pleural space is indicated in complicated disease.

Educational aims

To demonstrate that pleural TB incorporates a wide spectrum of disease, ranging from self-resolving lymphocytic effusions to severe TB empyema with serious sequelae.To emphasise the high coexistence of pulmonary TB with pleural TB, and the importance of obtaining sputum for culture (induced if necessary) in all cases.To explore the significant diagnostic challenges posed by pleural TB, and consequently the frequent lack of information about drug sensitivity prior to initiating treatment.To highlight the influence of underlying TB prevalence in the population on the diagnostic accuracy of adjunctive investigations for the diagnosis of pleural TB.To discuss concerns around penetration of anti-TB medications into the pleural space and how this can influence decisions around treatment duration in practice.

Biomarkers for distinguishing tuberculous pleural effusion from non-tuberculosis effusion: a retrospective study

BACKGROUND

Pleural effusion (PE) is a common clinical feature that presents a diagnostic challenge for clinicians. In this retrospective study, we aimed to assess the biomarkers, ratios, and multiple indicators in serum and Pleural effusion for the differential diagnosis of tuberculous pleural effusion (TPE) from non-tuberculosis effusion (non-TPE).

METHODS

The participants, who were divided into two groups: TPE and non-TPE (MPE and PPE), from Ningbo First Hospital, were incorporated in this study. The clinical and laboratory features were collected and analyzed using logistic regression analysis. Twelve biomarkers and their ratios in serum and PE were investigated for TPE versus non-TPE. Additionally, the value of multiple indicators for joint diagnosis was estimated.

RESULTS

Biomarkers and ratios showed good diagnostic performance. The five variables including Serum ADA, IGRA, Effusion ADA, Effusion ADA/Serum ADA and Effusion LDH/Effusion ADA were identified as valuable parameters for differential diagnosis of TPE from non-TPE. The combined diagnosis of the five indexes yielded the highest diagnostic accuracy for TPE with an AUC (0.919), sensitivity (90.30%), and specificity (94.50%).

CONCLUSIONS

The biomarkers and ratios demonstrated strong diagnostic performance, and the utilization of multiple indicators for joint diagnosis can improve the diagnostic efficacy of tuberculous pleurisy.

Construction of a multi-classified decision tree model for identifying malignant pleural effusion and tuberculous pleural effusion

OBJECTIVE

Pleural effusion (PE) is a common clinical complication associated with various disorders. We aimed to utilize laboratory variables and their corresponding ratios in serum and PE for the differential diagnosis of multiple types of PE based on a decision tree (DT) algorithm.

METHODS

A total of 1435 untreated patients with PE admitted to The First Affiliated Hospital of Ningbo University were enrolled. The demographic and laboratory variables were collected and compared. The receiver operating characteristic curve was used to select important variables for diagnosing malignant pleural effusion (MPE) or tuberculous pleural effusion (TPE) and included in the DT model. The data were divided into the training set and the test set at a ratio of 7:3. The training data was used to develop the DT model, and the test data was for evaluating the model. Independent data was collected as external validation.

RESULTS

Three PE indicators (carcinoembryonic antigen, adenosine deaminase [ADA], and total protein), two serum indicators (neuron-specific enolase and cytokeratin 19 fragments), and two ratios [high-sensitivity C-reactive protein (hsCRP)/ PE lymphocyte and hsCRP/PE ADA] were used to construct the DT model. The area under the curve (AUC), sensitivity, and specificity for diagnosing MPE were 0.963, 84.0%, 91.6% in the training set, 0.976, 84.1%, 88.6% in the test set, and 0.955,83.3%, 86.7% in the external validation set. The AUC, sensitivity, and specificity of diagnosing TPE were 0.898, 86.8%, 92.3% in the training set, 0.888, 88.8%, 92.7% in the test set, and 0.778, 84.8%, 94.3% in the external validation set.

CONCLUSION

The DT model showed good diagnostic efficacy and could be applied for the differential diagnosis of MPE and TPE in clinical settings.

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.

Adenosine deaminase-based measurement in the differential diagnosis of pleural effusion: a multicenter retrospective study

INTRODUCTION

The differential diagnosis of pleural effusion is difficult, and studies have reported on the potential role of adenosine deaminase (ADA) in the differential diagnosis of undiagnosed pleural effusion. This retrospective study aimed to investigate the diagnostic role of ADA in pleural effusion.

METHODS

266 patients with pleural effusion from three centers were enrolled. The concentrations of ADA and lactate dehydrogenase (LDH) were measured in pleural fluids and serum samples of the patients. The diagnostic performance of ADA-based measurement for tuberculous pleural effusion (TPE), malignant pleural effusion (MPE), and parapneumonic effusion (PPE) was examined by receiver operating characteristic (ROC) curve analysis.

RESULTS

An area under the ROC curve (AUC) value of 0.909 was obtained using the pleural ADA values as the indicator for TPE identification (sensitivity: 87.50%, specificity: 87.82%). The ratio of serum LDH to pleural ADA (cancer ratio) provided the predictive capacity with an AUC of 0.879 for MPE diagnosis (sensitivity: 95.04%, specificity: 67.06%). At a cut-off value of 14.29, the pleural ADA/LDH ratio showed a sensitivity and specificity of 81.13% and 83.67%, respectively, and a high AUC value of 0.888 for the differential diagnosis of PPE from TPE.

CONCLUSION

ADA-based measurement is helpful for the differential diagnosis of pleural effusion. Further studies should be performed to validate these results.

The Value of Adenosine Deaminase 2 in the Detection of Tuberculous Pleural Effusion: A Meta-Analysis and Systematic Review

Adenosine deaminase 2 (ADA2) is reported as a novel diagnostic biomarker for tuberculous pleural effusion (TPE) in many studies. This meta-analysis was conducted to systematically evaluate the general diagnostic performance of pleural ADA2 in TPE. After searching for relevant studies that investigated the diagnostic performance of pleural ADA2 in TPE in several databases, we assessed and selected eligible studies to calculate pooled parameters by STATA 16.0 software. A final set of thirteen studies entirely met the inclusion standards and were used to calculate pooled parameters in our meta-analysis. Among them, there were nine English studies and four Chinese studies. The pooled parameters of pleural ADA2 in diagnosing TPE were summarized as follows: sensitivity, 0.91 (95% CI: 0.86-0.95); specificity, 0.93 (95% CI: 0.92-0.95); positive likelihood ratio, 13.9 (95% CI: 10.6-18.3); negative likelihood ratio, 0.09 (95% CI:0.06-0.16); diagnostic odds ratio, 147 (95% CI: 76-284); and the area under the curve, 0.95 (95% CI: 0.93-0.97). Pleural ADA2 is a reliable indicator with excellent accuracy in TPE diagnosis. However, we need to combine pleural ADA2 with diverse examinations to diagnose TPE in clinical practice.

Development and validation of a prediction model for tuberculous pleural effusion: a large cohort study and external validation

Background

Distinguishing tuberculous pleural effusion (TPE) from non-tuberculosis (TB) benign pleural effusion (BPE) remains to be a challenge in clinical practice. The aim of the present study was to develop and validate a novel nomogram for diagnosing TPE.

Methods

In this retrospective analysis, a total of 909 consecutive patients with TPE and non-TB BPE from Ningbo First Hospital were divided into the training set and the internal validation set at a ratio of 7:3, respectively. The clinical and laboratory features were collected and analyzed by logistic regression analysis. A diagnostic model incorporating selected variables was developed and was externally validated in a cohort of 110 patients from another hospital.

Results

Six variables including age, effusion lymphocyte, effusion adenosine deaminase (ADA), effusion lactatedehy drogenase (LDH), effusion LDH/effusion ADA, and serum white blood cell (WBC) were identified as valuable parameters used for developing a nomogram. The nomogram showed a good diagnostic performance in the training set. A novel scoring system was then established based on the nomogram to distinguish TPE from non-TB BPE. The scoring system showed good diagnostic performance in the training set [area under the curve (AUC) (95% confidence interval (CI)), 0.937 (0.917–0.957); sensitivity, 89.0%, and specificity, 89.5%], the internal validation set [AUC (95%CI), 0.934 (0.902–0.966); sensitivity, 88.7%, and specificity, 90.3%], and the external validation set [(AUC (95%CI), 0.941 (0.891–0.991); sensitivity, 93.6%, and specificity, 87.5%)], respectively.

Conclusions

The study developed and validated a novel scoring system based on a nomogram originated from six clinical parameters. The novel scoring system showed a good diagnostic performance in distinguishing TPE from non-TB BPE and can be conveniently used in clinical settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02051-4.

Investigating the appropriate adenosine deaminase cutoff value for the diagnosis of tuberculous pleural effusion in a country with decreasing TB burden

As the burden of tuberculosis (TB) in South Korea decreases while that of malignancy increases with an aging society, the composition of etiology for pleural effusion is changing. The aim of this study was to investigate the diagnostic value of adenosine deaminase (ADA) for diagnosis of tuberculous pleural effusion (TPE) in this circumstance. Medical records of patients who underwent medical thoracoscopy from May 2015 to September 2020 in Incheon St. Mary Hospital, Korea were retrospectively reviewed. TPE was diagnosed if one of the following criteria was met: (1) granuloma in pleura, (2) positive TB polymerase chain reaction or culture in pleural fluid or tissue with non-specific pathologic findings in pleura, or (3) bacteriologically confirmed pulmonary TB with non-specific pathologic findings in pleura. A total of 292 patients, including 156 with malignant pleural effusion (MPE), 52 with TPE, and 84 with other benign effusion, were analyzed. Among 206 patients with lymphocyte dominant pleural effusion, the area under receiver characteristic curve of ADA for diagnosis of TPE was 0.971. The sensitivity and specificity of a current cutoff value of 40 IU/L were 1.00 and 0.61, respectively, whereas those of a raised cutoff value of 70 IU/L were 0.93 and 0.93, respectively. Among 54 patients with ADA levels of 40–70 IU/L, 30 (55.6%) patients were diagnosed as MPE, 21 (38.9%) as other benign effusion, and only 3 (5.6%) as TPE. Caution is needed in clinical diagnosis of TPE with current ADA cutoff value in countries with decreasing TB incidence, due to many false positive cases.

Diagnosing pleural effusions using mass spectrometry-based multiplexed targeted proteomics quantitating mid- to high-abundance markers of cancer, infection/inflammation and tuberculosis

Pleural effusion (PE) is excess fluid in the pleural cavity that stems from lung cancer, other diseases like extra-pulmonary tuberculosis (TB) and pneumonia, or from a variety of benign conditions. Diagnosing its cause is often a clinical challenge and we have applied targeted proteomic methods with the aim of aiding the determination of PE etiology. We developed a mass spectrometry (MS)-based multiple reaction monitoring (MRM)-protein-panel assay to precisely quantitate 53 established cancer-markers, TB-markers, and infection/inflammation-markers currently assessed individually in the clinic, as well as potential biomarkers suggested in the literature for PE classification. Since MS-based proteomic assays are on the cusp of entering clinical use, we assessed the merits of such an approach and this marker panel based on a single-center 209 patient cohort with established etiology. We observed groups of infection/inflammation markers (ADA2, WARS, CXCL10, S100A9, VIM, APCS, LGALS1, CRP, MMP9, and LDHA) that specifically discriminate TB-PEs and other-infectious-PEs, and a number of cancer markers (CDH1, MUC1/CA-15-3, THBS4, MSLN, HPX, SVEP1, SPINT1, CK-18, and CK-8) that discriminate cancerous-PEs. Some previously suggested potential biomarkers did not show any significant difference. Using a Decision Tree/Multiclass classification method, we show a very good discrimination ability for classifying PEs into one of four types: cancerous-PEs (AUC: 0.863), tuberculous-PEs (AUC of 0.859), other-infectious-PEs (AUC of 0.863), and benign-PEs (AUC: 0.842). This type of approach and the indicated markers have the potential to assist in clinical diagnosis in the future, and help with the difficult decision on therapy guidance.

Laboratory and radiological discrimination between tuberculous and malignant pleural effusions with high adenosine deaminase levels

BACKGROUND/AIMS

Pleural fluid adenosine deaminase (ADA) levels are useful in discriminating tuberculous pleural effusions (TPEs) from malignant pleural effusions (MPEs). However, some patients with MPE exhibit high-ADA levels, which may mimic TPEs. There is limited data regarding the differential diagnosis between high-ADA MPE and high-ADA TPE. This study aimed to identify the predictors for distinguishing high-ADA MPEs from high-ADA TPEs.

METHODS

Patients with TPE and MPE with pleural fluid ADA levels ≥ 40 IU/L were included in this study. Clinical, laboratory, and radiological data were compared between the two groups. Independent predictors and their diagnostic performance for high-ADA MPEs were evaluated using multivariate logistic regression analysis and receiver operating characteristic curve.

RESULTS

A total of 200 patients (high-ADA MPE, n = 30, and high-ADA TPE, n = 170) were retrospectively included. In the multivariate analysis, pleural fluid ADA, pleural fluid carcinoembryonic antigen (CEA), and pleural nodularity were independent discriminators between high-ADA MPE and high-ADA TPE groups. Using pleural ADA level of 40 to 56 IU/L (3 points), pleural CEA level ≥ 6 ng/mL (6 points), and presence of pleural nodularity (3 points) for predicting high-ADA MPEs, a sum score ≥ 6 points yielded a sensitivity of 90%, specificity of 96%, positive predictive value of 82%, negative predictive value of 98%, and area under the receiver operating characteristic curve of 0.965.

CONCLUSION

A scoring system using three parameters may be helpful in guiding the differential diagnosis between high-ADA MPEs and high-ADA TPEs.

Improved diagnosis of extrapulmonary tuberculosis in adults with and without HIV in Mbeya, Tanzania using the MPT64 antigen detection test

Extrapulmonary tuberculosis (EPTB) in People Living with HIV (PLWHIV) is a diagnostic challenge. Our immunochemistry based MPT64 antigen detection test has shown improved sensitivity compared to current laboratory tests in the resource limited diagnostic setting. The aim of this study was to validate the implementability and diagnostic performance of the test in PLWHIV and HIV negative adults in a HIV endemic Tanzanian setting. Adult (>18 y) presumptive EPTB patients were prospectively enrolled at Mbeya Zonal Referral Hospital and followed to the end of treatment or until an alternative diagnosis was reached. Suspected sites of infection were sampled and were subject to routine diagnostics, GeneXpert MTB/RIF assay and the MPT64 test. The performance of the diagnostics tests was assessed using a composite reference standard that included clinical suspicion, mycobacterial culture, response to anti-tuberculosis (TB) therapy, cytological and radiological findings. Patients (N = 168) were categorized as 21 confirmed TB, 23 probable TB and 44 possible TB cases, 69 patients were categorized as non-TB cases and 11 were uncategorized. In the TB group, the three most common infections were adenitis (41%), peritonitis (19%) and pleuritis (14%). The TB and non-TB groups did not differ in HIV seropositivity (46% vs 42%) Among HIV negative and PLWHIV, the MPT64 test had a sensitivity of (91% vs 78%), specificity (75% vs 86%), positive predictive value (80% vs 88%), negative predictive value (89% vs 74%), and accuracy (84% vs 81%), respectively. Performance was not significantly reduced in PLWHIV, and sensitivity was higher than in the currently used tests, including the GeneXpert MTB/RIF assay. The MPT64 test improved the diagnosis of EPTB, irrespective of HIV status. The test performed better than currently used diagnostic test. The test was implementable in a tertiary level hospital with basic pathology services in a HIV endemic Tanzanian setting.

Clinical and Epidemiological Features of Tuberculous Pleural Effusion in Alicante, Spain

We aimed to (1) evaluate the incidence of tuberculous pleural effusion (TPE) over 25 years in our centre; (2) measure the yield of different diagnostic techniques; (3) compare TPE features between immigrant and native patients. Retrospective study of patients who underwent diagnostic thoracentesis and pleural biopsy in our hospital between 1995 and 2020. TPE was diagnosed in 71 patients (65% natives, 35% immigrants). Onset was acute in 35%, subacute in 26% and prolonged in 39%. Radiological features were atypical in 42%. Thoracentesis specimens were lymphocyte-predominant in 84.5% of patients, with elevated adenosine deaminase in 75% of patients. Diagnostic yield of pleural biopsy was 78%. Compared with native patients, more immigrants had previous contact with TB (54% vs. 17%, p = 0.001), prior TB (21% vs. 4%, p < 0.02) and atypical radiological features (58% vs. 34%, p < 0.03). TPE incidence was six times higher in the immigrant population (6.7 vs. 1.1 per 100,000 person-years, p < 0.001). TPE has an acute onset and sometimes atypical radiological features. Pleural biopsy has the highest diagnostic yield. Reactivation, prior contact with TB, atypical radiological features, complications, and positive microbiology results are more common in immigrant patients.

MPT64 antigen detection test improves diagnosis of pediatric extrapulmonary tuberculosis in Mbeya, Tanzania

Pediatric extrapulmonary tuberculosis (EPTB) is a diagnostic challenge. A new immunochemistry based MPT64 antigen detection test has shown improved sensitivity compared to current laboratory tests. The aim of this study was to implement and validate the test performance in a resource limited African setting. Presumptive pediatric (0–18 y) EPTB patients were prospectively enrolled at Mbeya Zonal Referral Hospital, and followed to the end of treatment or until a final diagnosis was reached. Specimens from suspected sites of infection were subject to routine diagnostics, GeneXpert MTB/RIF assay and the MPT64 test. The performance of the tests was assessed using mycobacterial culture as well as a composite reference standard. 30 patients were categorized as TB cases, 31 as non-TB cases and 2 were uncategorized. In the TB group, the three most common infections were adenitis (30%), peritonitis (30%) and meningitis (20%). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the MPT64 test was 92%, 88%, 87%, 92% and 90%, respectively. Mortality was equally high among TB/non-TB cases (23% vs 21%), and malnutrition was the main comorbidity among TB cases. The MPT64 test was implementable in the routine diagnostics in a low-resource setting and improved the diagnosis of pediatric EPTB.

Biomarkers of Distinguishing Neutrophil-Predominant Tuberculous Pleural Effusion from Parapneumonic Pleural Effusion

BACKGROUND

Tuberculous pleural effusion (TPE) is usually characterized by lymphocytic predominance and high pleural fluid adenosine deaminase (pfADA), while parapneumonic pleural effusion (PPE) is usually characterized by neutrophilic predominance. However, in some cases, neutrophils can be predominant in TPE. In such cases, the differential diagnosis between TPE and PPE is challenging and has been rarely investigated. The aim of this study was to evaluate the accuracy of pfADA, pleural fluid lactate dehydrogenase (pfLDH) and other parameters, such as age/pfADA in the differential diagnosis of neutrophil-predominant TPE (NP-TPE) and PPE.

METHODS

Between January 2003 and August 2018, 19 patients with NP-TPE and 54 patients with PPE at Shanghai Jiao Tong University Affiliated Sixth People's Hospital were retrospectively reviewed. Age, blood and pleural fluid findings, and eight ratios that consisted of routine biomarkers were compared between the two groups in ≤50 and >50 years old groups. ROC curve analysis was used to evaluate diagnostic performance.

RESULTS

The three parameters with the largest AUC were age/pfADA, pfADA and pfLDH in ≤ 50 years old group, and pfADA, age/pfADA and the percentage of neutrophils in pleural fluid (pfN%) in >50 years old group. For patients ≤ 50 years old, pfADA combined with pfLDH or age/pfADA combined with pfLDH could increase the specificity to 100%, while the sensitivity of the former was high (84.6% vs 76.9%). For patients >50 years old, both pfADA combined with pfN% and age/pfADA combined with pfN% could increase the specificity to 90.3% with the same sensitivity.

CONCLUSIONS

Although pfADA played an important role in the discrimination of NP-TPE from PPE, combining pfADA with pfLDH for patients ≤50 years old or combining pfADA with pfN% for patients >50 years old might improve diagnostic performance.

Characteristics and survival impact of polymorphonuclear leucocyte-predominant malignant pleural effusions secondary to lung cancer

INTRODUCTION

In comparison with mononuclear leucocyte (MNL)-predominant malignant pleural effusions (MPEs), polymorphonuclear leucocyte (PMNL)-predominant MPEs have rarely been investigated and may be associated with a poorer prognosis.

OBJECTIVES

To investigate the characteristics and survival impact of PMNL-predominant MPEs secondary to lung cancer.

METHODS

This retrospective study included patients with MPE secondary to lung cancer, which were classified into the PMNL- and MNL-predominant groups according to cellular predominance in the pleural fluid. Clinical, hematological, radiological, and pleural fluid data were compared between the groups, and the survival impact of PMNL predominance in MPE was evaluated.

RESULTS

Of the 193 MPEs included, 37 (19%) were characterised by PMNL predominance. Compared to the MNL-predominant group, the PMNL-predominant group showed significantly poorer patient performances (P = .001), higher white blood cell counts (P = .009), higher neutrophil counts, higher blood neutrophil-to-lymphocyte ratio (P = .046), higher serum C-reactive protein (P = .003), lower serum albumin (P < .001), lower pleural fluid pH (P = .002) and higher pleural fluid lactate dehydrogenase (P = .029) levels. In contrast, most clinical and radiological findings, including the duration of symptoms, showed no significant intergroup differences. A shift towards MNL predominance was observed in only 38% of the PMNL-predominant patients who underwent repeat thoracentesis. Overall survival of the PMNL-predominant group was significantly shorter than the MNL-predominant group (P = .003).

CONCLUSIONS

PMNL predominance in MPEs secondary to lung cancer may be observed in variable phases with respect to the duration of symptoms and the time of thoracentesis. Overall, PMNL-predominant MPEs were associated with more advanced stages and poorer survival outcomes, compared to MNL-predominant MPEs.

Clinical and pathological differences between polymorphonuclear-rich and lymphocyte-rich tuberculous pleural effusion

OBJECTIVE

Analysis of the occurrence factors and disease characteristics of tuberculous (TB) pleural effusion (TPE) dominated by neutrophils.

METHODS

We retrospectively analyzed the clinical data of 304 patients with two types of TB pleurisy. The clinical, laboratory, and pathological features of TB pleurisy separately dominated by lymphocytes and neutrophils were analyzed.

RESULTS

Neutrophil-predominant effusion was observed in 33 (10.9%) patients. The patients with TPE with polymorphonuclear leukocytes (PMNLs) had higher fever rates and higher decortication rates than those with lymphocyte-predominant TPE. Otherwise, they had lower chest distress rates and lower positive rates of pulmonary TB and lower biopsy tissue culture-positive rates than patients with lymphocyte-predominant TPE. PMNL TPE patients had higher lactic acid dehydrogenase (LDH) (1297 vs. 410 U/l, P < 0.001) and adenosine deaminase (ADA) levels (54.1 vs. 42.9 U/l, P = 0.043) and lower pleural fluid glucose (1.92 vs. 4.70 mmol/L, P < 0.001) and protein (47.4 vs. 48.4 g/L, P = 0.024) levels than that of lymphocyte-predominant TPE. Otherwise, they had lower blood ALB levels and higher C-reactive protein levels than lymphocyte-predominant TPE. Finally, PMNL TPE patients had lower rates of granuloma formation (27.2% vs. 75.2%, P < 0.001) and pleural nodules than patients with lymphocyte-predominant TPE and more frequent findings of pus, caseous exudate, and necrosis.

CONCLUSION

The TB pleurisy patients dominated by neutrophils show strong inflammatory reactions and higher ADA levels in pleural effusion. These findings can significantly improve the positive rate of Mycobacterium tuberculosis in neutrophil-predominant TPE under thoracoscopy.

Mycoplasma pneumoniae infection mimicking tuberculous pleurisy in a young woman: a case report and literature review

A 30-year-old woman was admitted to a different hospital with a 2-day history of fever, cough, and expectoration. She had a history of left pulmonary tuberculosis 8 years previously. Chest computed tomography showed an infiltrate in the inferior lobe of the left lung and spot-like calcifications in the anterior lobe of the upper left lobe and lower lobe of the left lung. After antibacterial treatment, the patient’s condition deteriorated and she developed significant pleural effusion on the left side. The pleural effusion assay showed a lymphocyte-predominant exudate with a significantly increased adenosine deaminase level. The patient was transferred to our hospital with a suspected diagnosis of tuberculous pleuritis. A serum test for Mycoplasma pneumoniae-specific immunoglobulin M was positive. Because of the limitations of this test in determining the occurrence of recent infection, a thoracoscopic pleural biopsy was performed, and M. pneumoniae DNA was detected in the biopsy tissue using M. pneumoniae-specific polymerase chain reaction. Thus, the patient was diagnosed with M. pneumoniae-related parapneumonic effusion. Clinicians must be aware of the usefulness and limitations of a high adenosine deaminase level and know that lymphocyte predominance in pleural effusion does not always indicate tuberculous pleurisy, especially in areas of high tuberculosis prevalence.

Interpreting pleural fluid results

Interpreting pleural fluid results correctly requires an awareness of the possible aetiologies of a pleural effusion and an understanding of the reliability of the outcome of each investigation. All results must be interpreted within each different clinical context and knowledge of the pitfalls for each test is necessary when the diagnosis is unclear. This review aims to discuss the common aetiologies of a pleural effusion and some of the pitfalls in interpretation that can occur when the diagnosis is unclear.

Application of Venn's diagram in the diagnosis of pleural tuberculosis using IFN-γ, IP-10 and adenosine deaminase

BACKGROUND

Pleural tuberculosis (PlTB) is the most common extrapulmonary manifestation of this infectious disease which still presents high mortality rates worldwide. Conventional diagnostic tests for PlTB register multiple limitations, including the lack of sensitivity of microbiological methods on pleural specimens and the need of invasive procedures such as pleural biopsy performance. In this scenario, the search for biological markers on pleural fluid (PF) has been the target of several studies as a strategy to overcome the limitations of PlTB diagnosis. This study aims to evaluate the use either isolated or in combination with adenosine deaminase (ADA), interferon-gamma (IFN-γ), interferon-gamma inducible protein of 10-kD (IP-10) levels on PF in order to guide an accurate anti-TB treatment in microbiologically non-confirmed cases.

METHODS AND FINDINGS

Eighty patients presenting pleural effusion under investigation were enrolled in a cross-sectional study conducted at Pedro Ernesto University Hospital, Rio de Janeiro, RJ, Brazil. Peripheral blood (PB) and PF samples collected from all patients were applied to the commercial IFN-γ release assay, QuantiFERON-TB Gold In-Tube, and samples were analyzed for IFN-γ and IP-10 by immunoassays. ADA activity was determined on PF by the colorimetric method. Based on microbiological and histological criteria, patients were categorized as follow: confirmed PlTB (n = 16), non-confirmed PlTB (n = 17) and non-PlTB (n = 47). The Mycobacterium tuberculosis antigen-specific production of IFN-γ and IP-10 on PB or PF did not show significant differences. However, the basal levels of these biomarkers, as well as the ADA activity on PF, were significantly increased in confirmed PlTB in comparison to non-PlTB group. Receiver operating characteristics curves were performed and the best cut-off points of these three biomarkers were estimated. Their either isolated or combined performances (sensitivity [Se], specificity [Sp], positive predictive value [PPV], negative predictive value [NPV] and accuracy [Acc]) were determined and applied to Venn's diagrams among the groups. Based on the confirmed PlTB cases, IFN-γ showed the best performance of them at a cut-off point of 2.33 IU/mL (Se = 93.8% and Sp = 97.9%) followed by ADA at a cut-off of 25.80 IU/L (Se = 100% and Sp = 84.8%) and IP-10 (Cut-point = 4,361.90 pg/mL, Se = 75% and Sp = 82.6%). IFN-γ plus ADA (cut-point: 25.80 IU/L) represent the most accurate biomarker combination (98.4%), showing Se = 93.7%, Sp = 100%, PPV = 100% and NPV = 97.9%. When this analysis was applied in non-confirmed PlTB, 15/17 (88.2%) presented at least two positive biomarkers in combination.

CONCLUSION

IFN-γ, IP-10, and ADA in PlTB effusions are significantly higher than in non-PlTB cases. IFN-γ is an excellent rule-in and rule-out test compared to IP-10 and ADA. The combination of IFN-γ and ADA, in a reviewed cut-off point, showed to be particularly useful to clinicians as their positive results combined prompts immediate treatment for TB while both negative results suggest further investigation.

Tuberculous Pleural Effusion: Clinical Characteristics of 320 Patients

OBJECTIVES

To analyze the clinical and radiological characteristics and features of pleural fluid (PF) in patients with tuberculous pleural effusion (TPE).

METHODS

Retrospective analysis of TPEs treated in our clinic over the last 23years.

RESULTS

We included 320 patients with TPE (70% men; median age 33years). Mycobacterium tuberculosis was identified in the sputum or PF of 36% of the patients by microscopic examination, solid and liquid media cultures, or nucleic acid amplification tests. The greatest percentage of positive microbiological findings were associated with human immunodeficiency virus (HIV) co-infection (OR: 3.27), and with the presence in PF of proteins <4g/dL (OR: 3.53), neutrophils >60% (OR: 3.23), and glucose <40mg/dL (OR: 3.17). Pleural adenosine deaminase <35U/L was associated with TPEs that occupied less than half of the hemithorax (OR: 6.36) and with PF lactate dehydrogenase levels <500U/L (OR: 8.09). Radiological pulmonary opacities (30%) were more common in TPE occupying less than half of the hemithorax (OR: 2.73), in bilateral TPE (OR: 4.48), and in older patients (OR: 1.02). Factors predicting mortality were: HIV co-infection (OR: 24), proteins in PF <5g/dL (OR: 10), and greater age (OR: 1.05).

CONCLUSIONS

Patients with TPE and HIV co-infection and those with lower concentrations of proteins in PF had higher rates of positive microbiological results and death. Moreover, older patients had more pulmonary opacities and a higher incidence of death.

Pleural tuberculosis: medical thoracoscopy greatly increases the diagnostic accuracy

Our objective was to evaluate the efficacy of a standardised work-up in the diagnosis of pleural tuberculosis (TB) that included fibreoptic bronchoscopy and medical thoracoscopy.

A consecutive series of 52 pleural TB patients observed during the period 2001–2015 was evaluated retrospectively. 20 females, mean (range) age 39.7 (18–74) years, and 32 males, mean (range) age 45.75 (21–83) years, were included (28 non-EU citizens (53.8%)). The diagnosis of TB infections was established by identification (using stains, culture or molecular tests) of Mycobacterium tuberculosis in the pleura, sputum and/or bronchial specimens, or by evidence of caseous granulomas on pleural biopsies. Patients with and without lung lesions were considered separately.

The diagnostic yield of the microbiological tests on pleural fluid was 17.3% (nine out of 52 patients). Among the 18 patients with lung lesions, bronchial samples (washing, lavage or biopsy) were positive in 50% of cases (nine patients). Cultures of pleural biopsies were positive in 63% of cases (29 out of 46 patients); pleural histology was relevant in all patients. Without pleural biopsy, a diagnosis would have been reached in 15 out of 52 patients (28.6%) and in four of them only following culture at 30–40 days.

An integrated diagnostic work-up that includes all the diagnostic methods of interventional pulmonology is required for a diagnosis of pleural TB. In the majority of patients, a diagnosis can be reached only with pleural biopsy.

Diagnosis of tuberculous pleural effusion can be a challenge; medical thoracoscopy greatly increases accuracyhttp://ow.ly/EnY430gubm9

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.

Repeatability of pleural adenosine deaminase measurements in diagnostic evaluation of pleural effusions

BACKGROUND

A follow-up thoracentesis is proposed in suspected atypical tuberculosis cases. The study aimed to define the variability of pleural ADA values across repeated thoracenteses in different types of pleural effusions (PEs) and to evaluate whether ADA variance, in regard to the cutoff value of 40 U/L, affected final diagnosis.

METHODS

A total of 131 patients with PEs of various etiologies underwent three repeated thoracenteses. ADA values were subsequently estimated.

RESULTS

82% and 55% of patients had greater than 10% and 20% deviation from the highest ADA value, respectively. From those patients who had a variance of 20%, 36% had only increasing ADA values, while 19% had only decreasing values. Considering the cutoff value of 40 U/L, only in two cases, ADA decreased below this threshold, which concerned a man with tuberculous pleurisy and a woman with lymphoma both in the course of treatment. Furthermore, only in two cases with rising values, ADA finally exceeded the cutoff limit, which concerned a man with rheumatoid pleurisy and a man with tuberculous pleurisy. Surprisingly, malignant PEs (MPEs) showed a higher percentage of increasing values compared to all other exudates that did not, however, exceed the threshold.

CONCLUSION

The determination of pleural ADA levels is a reproducible method for rapid tuberculosis diagnosis. The detected measurement deviations do not appear to affect final diagnosis. In specific situations, repeated ADA measurements may be valuable in directing further diagnostic evaluation. More investigation is needed to elucidate the possible prognostic significance of the increasing trend in ADA values in MPEs.

The pleural fluid lactate dehydrogenase/adenosine deaminase ratio differentiates between tuberculous and parapneumonic pleural effusions

Background

Although pleural fluid lactate dehydrogenase (LDH) and adenosine deaminase (ADA) levels are often used to distinguish between tuberculous pleural effusion (TPE) and parapneumonic pleural effusion (PPE), this can be challenging as the LDH level may vary from normal to severely increased in PPE and a significantly elevated ADA is frequently measured in both conditions. In this study, we evaluated use of the pleural fluid LDH/ADA ratio as a new parameter to discriminate TPE from PPE.

Methods

A retrospective study was conducted in patients with pathologically-confirmed TPE (n = 72) and PPE (n = 47) to compare pleural fluid LDH and ADA levels and LDH/ADA ratios between the 2 groups. A receiver operating characteristic (ROC) curve was constructed for identifying TPE.

Results

The median pleural fluid LDH and ADA levels and LDH/ADA ratios in the TPE and PPE groups were: 364.5 U/L vs 4037 U/L (P < .001), 33.5 U/L vs 43.3 U/L (P = .249), and 10.88 vs 66.91 (P < .0001), respectively. An area under the ROC curve of 0.9663 was obtained using the LDH/ADA ratio as the indicator for TPE identification, and the sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were, respectively, 93.62%, 93.06%, 13.48, and 0.068 at a cut-off level of 16.20.

Conclusions

The pleural fluid LDH/ADA ratio, which can be determined from routine biochemical analysis, is highly predictive of TPE at a cut-off level of 16.20. Measurement of this parameter may be helpful for clinicians in distinguishing between TPE and PPE.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0526-z) contains supplementary material, which is available to authorized users.

Does repeated pleural culture increase the diagnostic yield of Mycobacterium tuberculosis from tuberculous pleural effusion in HIV-negative individuals?

Background

Despite recent advances in methods for culturing Mycobacterium tuberculosis (MTB), the diagnostic yield of tuberculous pleural effusion (TBPE) remains unsatisfactory. However, unlike repeated sputum cultures of pulmonary tuberculosis, little is known about the role of repeated pleural cultures. We examined whether repeated pleural cultures are associated with increased MTB yield from TBPE.

Methods

A multicenter, retrospective cohort study was performed from January 2012 to December 2015 in South Korea. Patients were categorized into two groups: single- or repeated-culture groups. The diagnostic yield of MTB and clinical, radiological, and pleural fluid characteristics were evaluated.

Results

Among the 329 patients with TBPE, 77 (23.4%) had repeated cultures and 252 (76.5%) had a single culture. Pleural culture was performed twice in all 77 patients in the repeated-culture group at a 1-day interval (inter-quartile range, 1.0–2.0). In the repeated-culture group, the yield of MTB from the first culture was 31.2%, which was similar to that in the single-culture group (31.2% vs. 29.8%, P = 0.887). However, the yield of MTB from the second culture (10/77, 13.0%) was more than that from the first. These results may be attributable to the insufficient immune clearance for MTB invasion into the pleural space between the first and second cultures. Over time, the yield of the second cultures decreased from 17.4% to 6.7% and then 6.3%. Finally, the overall yield of MTB in the repeated- and single-culture groups was 44.2% and 29.8% respectively (P < 0.001).

Conclusions

The results showed that repeated pleural cultures increased MTB yield from TBPE in human immunodeficiency virus-negative individuals. Furthermore, repeated cultures may increase yield when carried out for two consecutive days.

Loculated Tuberculous Pleural Effusion: Easily Identifiable and Clinically Useful Predictor of Positive Mycobacterial Culture from Pleural Fluid

Background

Isolation of M. tuberculosis (MTB) is required in cases of Tuberculous pleural effusion (TBPE) for confirming diagnosis and successful therapy based on drug sensitivity test. Several studies have focused on predictors of MTB culture positivity in TBPE. However, the clinical role of loculated TBPE as a predictor of MTB cultivation from TBPE remains unclear. The aim of this study was to examine possible predictors including loculation of TBPE of MTB culture positivity in TBPE.

Methods

We retrospectively examined associations between clinical, radiological, microbiological, and laboratory characteristics and positive MTB culture from TBPE to determine a potent predictor of culture positivity.

Results

From January 2011 to August 2015, 232 patients with TBPE were identified. Of these, 219 were finally analyzed. Among them, 69 (31.5%) were culture positive for MTB in TBPE and 86 (39.3%) had loculated TBPE. In multivariate logistic regression analysis, the loculation of TBPE was independently associated with culture positivity for MTB in TBPE (adjusted odds ratio [OR], 40.062; 95% confidence interval [CI], 9.355–171.556; p<0.001). In contrast, the lymphocyte percentage of TBPE (adjusted OR, 0.934; 95% CI, 0.899–0.971; p=0.001) was inversely associated with culture positivity for MTB in TBPE.

Conclusion

In clinical practice, identification of loculation in TBPE is easy, reliable to measure, not uncommon and may be helpful to predict the possibility of positive mycobacterial culture.

Clinical and Laboratory Differences between Lymphocyte- and Neutrophil-Predominant Pleural Tuberculosis

Pleural tuberculosis (TB), a form of extrapulmonary TB, can be difficult to diagnose. High numbers of lymphocytes in pleural fluid have been considered part of the diagnostic criteria for pleural TB; however, in many cases, neutrophils rather than lymphocytes are the predominant cell type in pleural effusions, making diagnosis more complicated. Additionally, there is limited information on the clinical and laboratory characteristics of neutrophil-predominant pleural effusions caused by Mycobacterium tuberculosis (MTB). To investigate clinical and laboratory differences between lymphocyte- and neutrophil-predominant pleural TB, we retrospectively analyzed 200 patients with the two types of pleural TB. Of these patients, 9.5% had neutrophil-predominant pleural TB. Patients with lymphocyte-predominant and neutrophil-predominant pleural TB showed similar clinical signs and symptoms. However, neutrophil-predominant pleural TB was associated with significantly higher inflammatory serum markers, such as white blood cell count (P = 0.001) and C-reactive protein (P = 0.001). Moreover, MTB was more frequently detected in the pleural fluid from patients in the neutrophil-predominant group than the lymphocyte-predominant group, with the former group exhibiting significantly higher rates of positive results for acid-fast bacilli in sputum (36.8 versus 9.4%, P = 0.003), diagnostic yield of MTB culture (78.9% versus 22.7%, P < 0.001) and MTB detected by polymerase chain reaction (31.6% versus 5.0%, P = 0.001). Four of seven patients with repeated pleural fluid analyses revealed persistent neutrophil-predominant features, which does not support the traditional viewpoint that neutrophil-predominant pleural TB is a temporary form that rapidly develops into lymphocyte-predominant pleural TB. In conclusion, neutrophil-predominant pleural TB showed a more intense inflammatory response and a higher positive rate in microbiological testing compared to lymphocyte-predominant pleural TB. Pleural TB should be considered in neutrophil-predominant pleural effusions, and microbiological tests are warranted.

Different characteristics of tuberculous pleural effusion according to pleural fluid cellular predominance and loculation

BACKGROUND

Tuberculous pleural effusion (TPE) exhibits different characteristics according to pleural fluid cellular predominance or whether the pleural fluid is free-flowing or loculated. However, its categorization based on either of these factors alone may be insufficient to properly reflect the heterogeneous manifestation of TPE. We evaluated the characteristics of the four TPE groups classified according to cellular predominance and whether the fluid is free-flowing or loculated.

METHODS

A cohort of 375 patients with TPE was retrospectively reviewed. Clinical, radiological, and laboratory findings were compared between neutrophilic and lymphocytic TPE, and between free-flowing and loculated effusion for both neutrophilic and lymphocytic TPE.

RESULTS

Lymphocytic TPE and neutrophilic TPE were observed in 336 (90%) and 39 (10%) patients, respectively. Pleural fluid loculation was present in 36% and 31% of the patients in the lymphocytic and neutrophilic groups, respectively. A few parameters of the laboratory findings between neutrophilic and lymphocytic TPE patients showed significant differences. However, these significant differences were prominently observed when comparing free-flowing and loculated subgroups of the respective neutrophilic and lymphocytic groups. Pleural fluid pH, lactate dehydrogenase, and adenosine deaminase levels were significantly different among the four subgroups. The neutrophilic loculated subgroup exhibited the most intense pleural inflammation and the highest mycobacterial yields when compared to the other subgroups. However, the percentage of neutrophils in the pleural fluid was not positively associated with the probability of culture-positive effusion.

CONCLUSIONS

The heterogeneous manifestation of TPE would be better characterized by using a classification system based on combined pleural fluid cellular predominance and loculation, with the neutrophilic loculated subgroup contributing to most of the clinically significant differences.

Advances in the diagnosis of tuberculous pleuritis

Pleural tuberculosis (TB) remains difficult to diagnose. In about two-thirds of the cases the diagnosis is reliant upon clinical suspicion along with consistent fluid biochemistries (i.e., lymphocytic predominant exudates) and exclusion of other potential causes for the effusion. Microbiological methods for a confirmatory diagnosis of pleural TB, which include acid-fast smears (Ziehl-Nelseen), cultures on solid media (Lowenstein-Jensen) and polymerase chain reaction tests from either pleural fluid or sputum samples, remain suboptimal since they are positive in only a minority of patients. Liquid media, however, significantly increase sensitivity while shortening culture positivity as compared with solid cultures. A number of pleural fluid biomarkers such as adenosine deaminase (ADA), interferon-Ƴ, interferon-Ƴ-induced protein of 10 KDa (IP-10) and interleukin-27 (IL-27), have shown promise for the rapid diagnosis of TB, but only ADA combines the accuracy and simplicity required to be considered a mainstay investigative tool for clinical decisions, particularly in areas with medium to high TB prevalence. In countries where ADA is not available, pleural biopsies to evaluate for caseating granulomas are a standard diagnostic approach. They are now frequently performed under ultrasound guidance to optimize yield and patient safety.

Pleural fluid adenosine deaminase/serum C-reactive protein ratio for the differentiation of tuberculous and parapneumonic effusions with neutrophilic predominance and high adenosine deaminase levels

PURPOSE

Tuberculous pleural effusion (TPE) and parapneumonic effusion (PPE) are usually distinguished by cellular predominance and pleural fluid adenosine deaminase (ADA) levels. However, both diseases may occasionally show similar neutrophilic predominance and high ADA levels. In such cases, the differential diagnosis between TPE and PPE is challenging and has been rarely investigated.

METHODS

A retrospective study was conducted on TPE and PPE patients with neutrophilic exudate and pleural fluid ADA levels ≥40 U/L. Individual and combined parameters of routine blood and pleural fluid tests were compared between the two groups, and receiver operating characteristic (ROC) curves were constructed for identifying TPE.

RESULTS

Thirty-six TPE and 41 PPE patients were included. White blood cell counts, serum C-reactive protein (S-CRP), and pleural fluid pH, lactate dehydrogenase, and ADA levels showed significant difference between the two groups (p < 0.001). Among multiple parameters, pleural fluid ADA/S-CRP ratio, which best reflected different local and systemic characteristics between TPE and PPE, provided the highest diagnostic accuracy with an area under the ROC curve of 0.93. At a cutoff value of 5.62, ADA/S-CRP ratio had a sensitivity of 89 %, specificity of 88 %, positive likelihood ratio of 7.29, and negative likelihood ratio of 0.13 for identifying TPE. Additionally, more than half of TPE patients had a ratio above 15.82, while none of PPE patients showed such findings.

CONCLUSIONS

Pleural fluid ADA/S-CRP ratio, as a simple method using routine laboratory tests, may be helpful in discriminating between TPE and PPE patients with neutrophilic predominance and ADA ≥40 U/L.

Neutrophilic Loculated Tuberculous Pleural Effusion: Incidence, Characteristics and Differentiation From Complicated Parapneumonic Effusion

OBJECTIVES

Tuberculous pleural effusion (TPE) is generally characterized by lymphocytic exudative effusion, either free-flowing or loculated. However, patients can also have neutrophilic loculated TPE, although little data are available concerning the incidence and characteristics of this form of TPE. It is important to differentiate between neutrophilic loculated TPE and complicated parapneumonic effusion (PPE), which also shows neutrophilic loculated effusion but needs a different management approach. The present study evaluated the incidence and characteristics of neutrophilic loculated TPE and differentiated it from complicated PPE.

MATERIALS AND METHODS

Between 2009 and 2014, a cohort of patients with TPE was retrospectively reviewed in a South Korean referral hospital. Clinical, laboratory, computed tomography and pleural fluid findings of patients with neutrophilic loculated TPE were compared to those of patients with neutrophilic free-flowing TPE and complicated PPE, respectively.

RESULTS

Neutrophilic TPE was observed in 33 (10%) out of 344 patients with TPE. Of these, 10 (30%) patients exhibited loculation of the pleural fluid. These patients showed distinct pleural fluid characteristics. The classical pleural fluid biomarker levels were more intense than those observed in 23 patients with neutrophilic free-flowing TPE, but similar to those of 54 patients with complicated PPE. A high mycobacterial burden was observed in the pleural fluid, and favorable outcomes were achieved with antituberculosis drug administration alone. Nodular parenchymal lesions and pleural fluid adenosine deaminase levels were independent discriminators of neutrophilic loculated TPE and PPE.

CONCLUSIONS

These results may be helpful to understand and manage patients with neutrophilic loculated TPE and differentiate them from patients with complicated PPE.

Pleural effusion adenosine deaminase: a candidate biomarker to discriminate between Gram-negative and Gram-positive bacterial infections of the pleural space

OBJECTIVES

Delay in the treatment of pleural infection may contribute to its high mortality. In this retrospective study, we aimed to evaluate the diagnostic accuracy of pleural adenosine deaminase in discrimination between Gram-negative and Gram-positive bacterial infections of the pleural space prior to selecting antibiotics.

METHODS

A total of 76 patients were enrolled and grouped into subgroups according to Gram staining: 1) patients with Gram-negative bacterial infections, aged 53.2±18.6 years old, of whom 44.7% had empyemas and 2) patients with Gram-positive bacterial infections, aged 53.5±21.5 years old, of whom 63.1% had empyemas. The pleural effusion was sampled by thoracocentesis and then sent for adenosine deaminase testing, biochemical testing and microbiological culture. The Mann-Whitney U test was used to examine the differences in adenosine deaminase levels between the groups. Correlations between adenosine deaminase and specified variables were also quantified using Spearman's correlation coefficient. Moreover, receiver operator characteristic analysis was performed to evaluate the diagnostic accuracy of pleural effusion adenosine deaminase.

RESULTS

Mean pleural adenosine deaminase levels differed significantly between Gram-negative and Gram-positive bacterial infections of the pleural space (191.8±32.1 U/L vs 81.0±16.9 U/L, p<0.01). The area under the receiver operator characteristic curve was 0.689 (95% confidence interval: 0.570, 0.792, p<0.01) at the cutoff value of 86 U/L. Additionally, pleural adenosine deaminase had a sensitivity of 63.2% (46.0-78.2%); a specificity of 73.7% (56.9-86.6%); positive and negative likelihood ratios of 2.18 and 0.50, respectively; and positive and negative predictive values of 70.6% and 66.7%, respectively.

CONCLUSIONS

Pleural effusion adenosine deaminase is a helpful alternative biomarker for early and quick discrimination of Gram-negative from Gram-positive bacterial infections of the pleural space, which is useful for the selection of antibiotics.

Atypical Pleural Fluid Profiles in Tuberculous Pleural Effusion: Sequential Changes Compared with Parapneumonic and Malignant Pleural Effusions

Objective Although tuberculous pleural effusion (TPE) is commonly characterized by lymphocytic predominance and high adenosine deaminase (ADA) levels, it may present with neutrophilic predominance or low ADA levels, which are more commonly found in parapneumonic effusion (PPE) or malignant pleural effusion (MPE), respectively. A few studies have observed that the atypical pleural fluid profiles of these cases of TPE may resolve at follow-up thoracentesis. However, these observations were incompletely analyzed and lacked comparison with proper control groups. Thus, limited data are available comparing the sequential pleural fluid changes between TPE and PPE or MPE with similar pleural fluid profiles. Methods TPE, PPE, and MPE patients who underwent sequential thoracentesis were retrospectively reviewed. The sequential changes in the pleural fluid profiles were compared between neutrophilic TPE and PPE, and lymphocytic TPE and MPE with low ADA levels. Results Twenty-three TPE patients (16 with neutrophilic exudates, seven with lymphocytic exudates), 72 cases of PPE with neutrophilic exudates, and 18 cases of MPE with lymphocytic exudates were included in the analysis. A sequential shift to lymphocytic exudates occurred significantly more often in TPE than in PPE cases. The initial and follow-up ADA levels in TPE cases with a lymphocytic shift were significantly higher than those in PPE cases with a lymphocytic shift. The ADA levels in the TPE cases with initial lymphocytic exudates and low ADA levels significantly increased at follow-up thoracentesis. For the TPE and MPE cases with initial lymphocytic exudates and ADA levels <40 U/L, the frequency of effusion with ADA levels ≥40 U/L at the second thoracentesis was significantly higher in the TPE cases. Conclusion Follow-up thoracentesis may provide useful information for clinical decision-making in suspected atypical TPE cases with neutrophilic exudates or low ADA levels.

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.

Impact of Implementation of an Automated Liquid Culture System on Diagnosis of Tuberculous Pleurisy

This study was conducted to evaluate the impact of implementation of an automated liquid culture system on the diagnosis of tuberculous pleurisy in an HIV-uninfected patient population. We retrospectively compared the culture yield, time to positivity, and contamination rate of pleural effusion samples in the BACTEC Mycobacteria Growth Indicator Tube 960 (MGIT) and Ogawa media among patients with tuberculous pleurisy. Out of 104 effusion samples, 43 (41.3%) were culture positive on either the MGIT or the Ogawa media. The culture yield of MGIT was higher (40.4%, 42/104) than that of Ogawa media (18.3%, 19/104) (P<0.001). One of the samples was positive only on the Ogawa medium. The median time to positivity was faster in the MGIT (18 days, range 8-32 days) than in the Ogawa media (37 days, range 20-59 days) (P<0.001). No contamination or growth of nontuberculous mycobacterium was observed on either of the culture media. In conclusion, the automated liquid culture system could provide approximately twice as high yields and fast results in effusion culture, compared to solid media. Supplemental solid media may have a limited impact on maximizing sensitivity in effusion culture; however, further studies are required.

Diagnosis and treatment of extrapulmonary tuberculosis

Extrapulmonary tuberculosis (EPTB) constitutes about 20% of all cases of tuberculosis (TB) in Korea. Diagnosing EPTB remains challenging because clinical samples obtained from relatively inaccessible sites may be paucibacillary, thus decreasing the sensitivity of diagnostic tests. Whenever practical, every effort should be made to obtain appropriate specimens for both mycobacteriologic and histopathologic examinations. The measurement of biochemical markers in TB-affected serosal fluids (adenosine deaminase or gamma interferon) and molecular biology techniques such as polymerase chain reaction may be useful adjuncts in the diagnosis of EPTB. Although the disease usually responds to standard anti-TB drug therapy, the ideal regimen and duration of treatment have not yet been established. A paradoxical response frequently occurs during anti-TB therapy. It should be distinguished from other causes of clinical deterioration. Surgery is required mainly to obtain valid diagnostic specimens and to manage complications. Because smear microscopy or culture is not available to monitor patients with EPTB, clinical monitoring is the usual way to assess the response to treatment.

Clinical Aspects of Adult Tuberculosis

Tuberculosis (TB) in adults can present in a large number of ways. The lung is the predominant site of TB. Primary pulmonary TB should be distinguished from postprimary pulmonary TB, which is the most frequent TB manifestation in adults (70%-80% cases). Cough is common, although the chest radiograph often raises suspicion of disease. Sputum sampling is a key step in the diagnosis of TB, and invasive procedures such as bronchoscopy may be necessary to achieve adequate samples for diagnosis. Extrapulmonary involvement, which may present many years after exposure, occurs in a variable proportion of cases (20%-45%). This reflects the country of origin of patients and also the frequency of associated human immunodeficiency virus (HIV) coinfection. In the latter case, the presentation of TB is often nonspecific, and care needs to be taken to not miss the diagnosis. Anti-TB therapy should be given in line with proven (or assumed) drug resistance. In extrapulmonary TB, adjunctive therapeutic measures may be indicated; although in all cases, support is often required to ensure that people are able to complete treatment with minimal adverse events and maximal adherence to the prescribed regimen, and so reduce risk of future disease for themselves and others.

Radiologic and laboratory differences in patients with tuberculous and parapneumonic pleural effusions showing non-lymphocytic predominance and high adenosine deaminase levels

PURPOSE

Tuberculous pleural effusion (TPE) is characterized by lymphocytic predominance and high adenosine deaminase (ADA) levels. However, TPEs sometimes present non-lymphocytic predominance, and parapneumonic effusion (PPE) often exceeds the cutoff value of ADA for TPE. Thus, the differential diagnosis of cases with pleural fluid (PF) showing non-lymphocytic predominance and high ADA levels is challenging. However, limited data concerning the clinical differences in these patients are available.

METHODS

A retrospective study was conducted on TPE and PPE patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L in 2009-2013 in a South Korean tertiary referral hospital. The clinical, laboratory, and computed tomography (CT) findings between the groups were analyzed using multivariate logistic regression to develop a prediction model with independent factors for TPE.

RESULTS

Among 353 patients with TPE, 24 (6.8 %) showed PF with non-lymphocytic predominance and ADA levels of ≥40 U/L. Twenty-eight PPE patients who presented PF findings comparable with those of TPE patients were included in the control group. In the final analysis, PF ADA levels >58 U/L and nodular lung lesions on CT were independent positive predictors, while loculated effusion was an independent negative predictor for TPE. Using the prediction model, a score ≥ +3 provided a sensitivity of 88 %, specificity of 93 %, positive predictive value of 91 %, and negative predictive value of 90 % for TPE.

CONCLUSION

PF ADA levels, nodular lung lesions, and loculated pleural effusion may help differentiate TPE from PPE in patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L.

Evaluation of Cepheid's Xpert MTB/Rif test on pleural fluid in the diagnosis of pleural tuberculosis in a high prevalence HIV/TB setting

BACKGROUND

Diagnosis of pleural tuberculosis (TB) using routinely available diagnostic methods is challenging due to the paucibacillary nature of the disease. Histopathology and pleural tissue TB culture involves an invasive procedure which requires expertise and appropriate equipment, both often unavailable in many health units. Xpert MTB/Rif test has been widely evaluated in sputum specimens but data on its performance in pleural TB is scarce. We evaluated the accuracy of Cepheid's Xpert MTB/Rif test on pleural fluid in the diagnosis of pleural TB in Uganda.

METHODS

Consenting adult patients with exudative pleural effusions underwent pleural biopsy and the tissue obtained subjected to Lowenstein-Jensen and mycobacterial growth indicator tube MTB cultures and histopathology. Pleural fluid for Xpert MTB/Rif testing was also collected. Data on socio-demographic characteristics, clinical symptoms, HIV status and CD4 count were also collected. Sensitivity, specificity, positive and negative predictive values of Xpert MTB/Rif test on pleural fluid in pleural TB diagnosis were calculated using pleural tissue MTB culture and/or histopathology as the reference standard.

RESULTS

Of the 116 participants [female 50%, mean age 34 (SD ±13], 87/116 (75%) had pleural TB confirmed on pleural tissue culture and/or histopathology. The Xpert MTB/Rif test identified 25 (28.7%) of the 87 confirmed pleural TB cases. The sensitivity and specificity of Xpert MTB/Rif test were 28.7% and 96.6% respectively while the positive and negative predictive values were 96.1% and 31.1% respectively.

CONCLUSION

Xpert MTB/Rif test on pleural fluid does not accurately diagnose pleural TB and therefore cannot be used as an initial evaluation test in patients with suspected pleural TB. New, rapid and accurate tests for the diagnosis of pleural TB are still warranted.