Revisiting tuberculous pleurisy: pleural fluid characteristics and diagnostic yield of mycobacterial culture in an endemic area

Microbiological confirmation of tuberculous pleurisy with medical thoracoscopy: targeted pleural washing and pleural biopsy

Background

Due to the pauci-bacillary nature of tuberculous (TB) pleurisy, clinical diagnosis is common, but microbiological confirmation is necessary to determine drug resistance. This study aimed to investigate the diagnostic yield of medical thoracoscopy (MT) for microbiological confirmation of TB pleurisy.

Methods

Medical records of patients diagnosed as TB pleurisy with microbiological or histologic evidence who underwent MT between May 2015 and July 2023 at Incheon St. Mary's Hospital were retrospectively reviewed. Sensitivities of microbiological results [acid-fast bacilli (AFB) culture or TB-polymerase chain reaction (PCR)] of pre-MT pleural fluid and those of targeted pleural washing fluid and pleural tissues obtained during MT were compared. Difference in sensitivity was verified with McNemar's test.

Results

A total of 72 patients were enrolled. With pre-MT pleural fluid, sensitivities of AFB culture and TB PCR were 5.6% (4/72) and 1.4% (1/72), respectively. With targeted pleural washing fluid, sensitivities of AFB culture and TB-PCR were 23.6% (17/72) and 12.5% (9/72), respectively. With pleural tissues, sensitivities of AFB culture and TB-PCR were 18.1% (13/72) and 40.3% (29/72), respectively. MT showed an additional 27.8% [95% confidence interval (95% CI): 14.2-40.1%, P<0.001] of sensitivity gain in AFB culture and 40.3% (95% CI: 25.7-52.5%, P<0.001) of sensitivity gain in TB-PCR. With pleural washing, additional 19.4% (95% CI: 6.8-31.6%, P=0.001) of sensitivity gain in microbiological confirmation was identified, whereas additional 37.5% (95% CI: 22.6-50.2%, P<0.001) of sensitivity gain was identified with pleural biopsy.

Conclusions

With MT, 44.4% of additional sensitivity gain in microbiological confirmation of TB pleurisy was identified. This underscores the role of MT in the diagnosis of TB pleurisy.

Meigs syndrome presenting with recurrent unilateral pleural effusion

Pelvic tumours are a rare cause of pleural effusion. We describe an approach to a case of Meigs syndrome with recurrent unilateral pleural effusion. A woman in her 60s' presented with recurrent right-sided pleural effusion, leading to cough and shortness of breath. Thoracentesis yielded exudative pleural fluid with cytology negative for malignancy. Pleuroscopy revealed inflamed pleura, and pleural biopsy was consistent with inflammatory changes. The patient's cancer antigen 125 level was elevated at 256 U/mL. Given the high suspicion of malignancy, a computed tomography scan of the chest, abdomen, and pelvis was performed and revealed ascites and a large left ovarian and uterine mass. The patient underwent a total abdominal hysterectomy and bilateral salphingo oophorectomy after experiencing three additional episodes of pleural effusion. Histological examination revealed the left ovarian mass to be a cellular fibroma and the uterine masses to be leiomyomata. Following the operation, there was no recurrence of pleural effusion.

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.

Non-traumatic Diaphragmatic Eventration With Extrapulmonary Tuberculosis Presenting As Pleural Effusion in an Indian Male: The First Report of Its Type

Tuberculosis is rampant in endemic countries. Extrapulmonary tuberculosis, like pleural effusion, is infrequently reported in outpatient departments. However, diaphragmatic eventration is rare and is not reported in active tuberculosis. Herein, the first-of-its-type case of a diaphragmatic eventration with tuberculous right pleural effusion in an Indian male is presented. The diagnosis was challenging and achieved through radiometric investigations and diagnostic pleural tapping. He was put on an anti-tuberculous treatment based on his weight.

Differential Diagnosis of Pleural Effusion Using Machine Learning

Rationale: Differential diagnosis of pleural effusion is challenging in clinical practice. Objectives: We aimed to develop a machine learning model to classify the five common causes of pleural effusions. Methods: This retrospective study collected 49 features from clinical information, blood, and pleural fluid of adult patients who underwent diagnostic thoracentesis between October 2013 and December 2018. Pleural effusions were classified into the following five categories: transudative, malignant, parapneumonic, tuberculous, and other. The performance of five different classifiers, including multinomial logistic regression, support vector machine, random forest, extreme gradient boosting, and light gradient boosting machine (LGB), was evaluated in terms of accuracy and area under the receiver operating characteristic curve through fivefold cross-validation. Hybrid feature selection was applied to determine the most relevant features for classifying pleural effusion. Results: We analyzed 2,253 patients (training set, n = 1,459; validation set, n = 365; extra-validation set, n = 429) and found that the LGB model achieved the best performance in both validation and extra-validation sets. After feature selection, the accuracy of the LGB model with the selected 18 features was equivalent to that with all 49 features (mean ± standard deviation): 0.818 ± 0.012 and 0.777 ± 0.007 in the validation and extra-validation sets, respectively. The model's mean area under the receiver operating characteristic curve was as high as 0.930 ± 0.042 and 0.916 ± 0.044 in the validation and extra-validation sets, respectively. In our model, pleural lactate dehydrogenase, protein, and adenosine deaminase levels were the most important factors for classifying pleural effusions. Conclusions: Our LGB model showed satisfactory performance for differential diagnosis of the common causes of pleural effusions. This model could provide clinicians with valuable information regarding the major differential diagnoses of pleural diseases.

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.

Conditional diagnostic accuracy according to inflammation status and age for diagnosing tuberculous effusion

BACKGROUND

Tuberculous effusion varies from lymphocyte-dominant to neutrophilic effusion according to inflammation status. The criteria of adenosine deaminase (ADA) and lymphocyte/neutrophil (L/N) ratio have yet not been evaluated across different disease conditions.

METHODS

Patients who conducted pleural fluid analysis from 2009 to 2019 at Asan Medical Center were included. Criteria (ADA of 50 and L/N ratio of 0.75) were evaluated by quantile subgroups according to age, C-reactive protein (CRP), white blood cell (WBC), and lactate dehydrogenase (LD) by the Monte Carlo simulation method to diagnose tuberculosis. The model for the ADA and L/N ratio was evaluated by AUROC.

RESULTS

Among the 2,918 reviewed cases, 2034 were included with 229 (11.26%) tuberculosis cases. The mean baseline ADA AUROC was 0.88 across all patients. Increased CRP and WBC showed high proportions of neutrophilic tuberculous effusion, with low sensitivity of approximately 45% and 33% in the fifth WBC and CRP groups, respectively. The AUROC of the models decreased with the increase in WBC and CRP groups (ADA model: 0.69 [the top quantile WBC group], 0.74 [the top quantile CRP group]). The AUROC of the models did not show a trend according to the increase in LD and age.

CONCLUSION

Inflammatory status affects the diagnostic metrics for tuberculous effusion due to the progression of tuberculous effusion. Clinicians should consider the low accuracy of tuberculous effusion criteria in high-inflammatory conditions when diagnosing tuberculosis.

Pleural Pustule-a Novel Thoracoscopic Appearance of Pleural Tuberculosis

BACKGROUND

Thoracoscopic pleural biopsy is the gold standard for diagnosing tubercular pleural effusion (TPE). Various thoracoscopic appearances like sago grain nodules, caseous necrosis, and adhesions have been described in TPE. However, none of these have high specificity for diagnosing TPE. In this study we evaluate a novel finding on thoracoscopy, the " Pleural Pustule."

METHODS

This is a retrospective analysis of patients who underwent thoracoscopy for undiagnosed pleural effusion. Visual inspection of the pleura was performed to identify abnormalities. Biopsies were obtained from those areas and sent for histopathology, acid fast bacillus (AFB) smear, culture, and Xpert MTB/Rif assay. Pleural pustule was defined as a pus filled nodule on the pleural surface.

RESULTS

Of the 259 patients included, 92 were diagnosed with TPE. Pleural pustule(s) were identified in 16 patients with TPE. Presence of pleural pustule had a sensitivity, specificity, positive predictive value, and negative predictive value of 17.4%, 100%, 100% and 68.7%, respectively, for diagnosing TPE. Histopathology of pleural pustule demonstrated necrotizing granulomas in all. In patients with pleural pustule, a microbiological diagnosis of tuberculosis was achieved in 93.7% patients (AFB smear, Xpert MTB/Rif assay, and MTB culture positive in 31.3%, 93.7%, and 43.7% cases, respectively). There is a strong association between pleural pustule and positive Xpert MTB/Rif assay ( P =0.002) and microbiologic confirmation of diagnosis ( P =0.017).

CONCLUSION

The presence of pleural pustule on thoracoscopy has a high positive predictive value for TPE. In tuberculosis-endemic countries, this can be considered suggestive for TPE. When identified, a biopsy from the pleural pustule should be performed as it will likely yield a positive microbiologic diagnosis.

The diagnostic value of interleukin-36 cytokines in pleural effusions of varying etiologies

BACKGROUND

The clinical management of pleural effusion (PE) poses challenges due to its diverse etiologies. The objective of this research was to investigate the concentrations of interleukin-36 (IL-36) cytokines in pleural fluid (PF) from different etiologies and assess their diagnostic efficacy in distinguishing the causes of PE.

METHODS

This study enrolled 89 patients with confirmed PE, comprising 11 cases classified as transudate, 24 cases as malignant pleural effusion (MPE), 24 cases as tuberculous pleural effusion (TPE), and 30 cases as parapneumonic pleural effusion (PPE). The PPE group was further subdivided into 20 cases of uncomplicated parapneumonic effusion (UPPE) and 10 cases of complicated parapneumonic effusion (CPPE)/empyema. The concentrations of IL-36 cytokines in the PF of all 89 patients were quantified by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

IL-36α exhibited excellent diagnostic accuracy in TPE, achieving a sensitivity of 91.7 % and specificity of 83.1 %, along with a cut-off value of 435.3 pg/ml. IL-36Ra also demonstrated relatively favorable diagnostic performance in PPE, with a sensitivity of 80.0 % and specificity of 76.3 %, along with a cut-off value of 390.8 pg/ml. Multivariable logistic regression models were successfully developed for both TPE and PPE, confirming their diagnostic utility. Furthermore, the levels of IL-36Ra were notably elevated in CPPE/empyema in comparison to UPPE. Moreover, in PF, IL-36γ exhibited positive associations with both IL-36α and IL-36Ra.

CONCLUSION

IL-36α and IL-36Ra may serve as novel biomarkers for diagnosing TPE and PPE, respectively. The multivariate models established significantly enhance the diagnostic efficacy of both TPE and PPE. Furthermore, IL-36Ra can function as an indicator for assessing the extent of pleural inflammation. Additionally, the interaction among IL-36 cytokines in PF may contribute to their expression modulation.

Single-cell profiling reveals distinct immune response landscapes in tuberculous pleural effusion and non-TPE

Background

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb) and remains a major health threat worldwide. However, a detailed understanding of the immune cells and inflammatory mediators in Mtb-infected tissues is still lacking. Tuberculous pleural effusion (TPE), which is characterized by an influx of immune cells to the pleural space, is thus a suitable platform for dissecting complex tissue responses to Mtb infection.

Methods

We employed singe-cell RNA sequencing to 10 pleural fluid (PF) samples from 6 patients with TPE and 4 non-TPEs including 2 samples from patients with TSPE (transudative pleural effusion) and 2 samples with MPE (malignant pleural effusion).

Result

Compared to TSPE and MPE, TPE displayed obvious difference in the abundance of major cell types (e.g., NK, CD4+T, Macrophages), which showed notable associations with disease type. Further analyses revealed that the CD4 lymphocyte population in TPE favored a Th1 and Th17 response. Tumor necrosis factors (TNF)-, and XIAP related factor 1 (XAF1)-pathways induced T cell apoptosis in patients with TPE. Immune exhaustion in NK cells was an important feature in TPE. Myeloid cells in TPE displayed stronger functional capacity for phagocytosis, antigen presentation and IFN-γ response, than TSPE and MPE. Systemic elevation of inflammatory response genes and pro-inflammatory cytokines were mainly driven by macrophages in patients with TPE.

Conclusion

We provide a tissue immune landscape of PF immune cells, and revealed a distinct local immune response in TPE and non-TPE (TSPE and MPE). These findings will improve our understanding of local TB immunopathogenesis and provide potential targets for TB therapy.

The incidence of tuberculous pleurisy in mainland China from 2005 to 2018

Background

Currently, tuberculous pleurisy (TP) remains a serious problem affecting global public health, including in China. Our purpose was to comprehensively understand and identify the incidence of TP in mainland China between 2005 and 2018.

Methods

The data on registered TP cases from 2005 to 2018 were acquired from the National Tuberculosis Information Management System. We analyzed the demographics, epidemiology, and time-space distribution of TP patients. Then, the effects of potentially influential factors on TP incidences, such as medical expenses per capita, GDP per capita, and population density, were assessed using the Spearman correlation coefficient.

Results

The incidence of TP increased in mainland China from 2005 to 2018, with a mean incidence of 2.5 per 100,000 population. Interestingly, spring was the peak season for TP, with more notified cases. Tibet, Beijing, Xinjiang, and Inner Mongolia had the highest mean annual incidence. A moderate positive relationship was found between TP incidence, medical expenses per capita, and GDP per capita.

Conclusions

The notified incidence of TP had an elevated trend from 2005 to 2018 in mainland China. The findings of this study provide insight into the knowledge of TP epidemiology in the country, which can help optimize resource allocation to reduce the TP burden.

Bacillary Positive Tuberculous Body Fluid Smears: A Perspective on How Fast to Use Acid Fast

Background Tuberculous effusions are common. Classically, they are described as bacteria poor and lymphocyte rich. Our experience, however, has been more varied. We compiled this rare group of bacteria-positive tuberculous fluids to document their cytologic spectrum and to look for possible predictors of bacillary positivity. Methods Fifty-one cases of bacillary positive fluids were identified and their clinicopathological details were noted. Per case, the smear background was assigned as either clear, caseous, suppurative, granular proteinaceous or frankly hemorrhagic. Fine, punched-out vacuoles in the smear background were also noted. The bacillary load in each case was classified from scanty to 3+. Eventually, the clinicopathologic variables were tabulated for frequency and studied for any association with bacillary presence. Results Only 19 of the 51 patients had a history of tuberculosis. Retropositive patients comprised a small proportion (9.8%) and did not always indicate strong (3+) bacillary positivity. The granular proteinaceous background was the most frequent (35%) pattern. Only a suppurative background was associated with strong bacillary positivity. Fine vacuoles were seen almost always with caseous and granular proteinaceous backgrounds but without statistical significance. Conclusion Tuberculous effusions can have diverse smear backgrounds, not necessarily one rich in caseous material. When tuberculosis is known or clinically suspected, non-classical findings such as abundant neutrophils or suppurative background should not dissuade one from requisitioning mycobacterial stains. In fact, acid-fast stains should probably routinely accompany Giemsa slides of clinically idiopathic effusions in endemic areas since it is still the cheapest and fastest method for a conclusive diagnosis.

Pulmonary tuberculosis among patients of tubercular pleural effusion: A single-center experience

Objective

To find out the prevalence of active pulmonary tuberculosis (TB) amongst patients of tubercular pleural effusion and to find out any direct association between tubercular pleural effusion and active pulmonary TB.

Methods

This was an observational study conducted in eastern India amongst patients of tubercular pleural effusion. Laboratory and radiological investigations were done for all of the patients. Patients with microbiological/radiological evidence of active pulmonary TB were classified as having primary disease. Rest of the patients were classified as having reactivated disease.

Results

A total of 50 patients were recruited in this study. Only 4 patients (8%) had radiological/microbiological evidence of active parenchymal TB. There was no difference in terms of demographic and laboratory features between patients with primary and reactivated disease.

Conclusion

Active pulmonary TB was found amongst a minority (4%) of cases of tubercular pleural effusion with reactivation of the past or, latent TB infection being responsible for the majority of the cases.

Changes in Etiology and Clinical Outcomes of Pleural empyema during the COVID-19 Pandemic

Healthcare-seeking behavior changed during the COVID-19 pandemic and might alter the epidemiology of pleural empyema. In this study, the incidence, etiology and outcomes of patients admitted for pleural empyema in Hong Kong in the pre-COVID-19 (January 2015-December 2019) and post-COVID-19 (January 2020-June 2022) periods were compared. Overall, Streptococcus pneumoniae was the predominant organism in <18-year-old patients, while Streptococcus anginosus, anaerobes and polymicrobial infections were more frequent in adults. In the post-COVID-19 period, a marked decline in the incidence of pleural empyema in children was observed (pre-COVID-19, 18.4 ± 4.8 vs. post-COVID-19, 2.0 ± 2.9 cases per year, p = 0.036), while the incidence in adults remained similar (pre-COVID-19, 189.0 ± 17.2 vs. post-COVID-19, 198.4 ± 5.0 cases per year; p = 0.23). In the post-COVID-19 period, polymicrobial etiology increased (OR 11.37, p < 0.0001), while S. pneumoniae etiology decreased (OR 0.073, p < 0.001). In multivariate analysis, clinical outcomes (length of stay, ICU admission, use of intrapleural fibrinolytic therapy, surgical intervention, death) were not significantly different in pre- and post-COVID-19 periods. In conclusion, an increase in polymicrobial pleural empyema was observed during the pandemic. We postulate that this is related to the delayed presentation of pneumonia to hospitals.

Complement regulatory proteins: Candidate biomarkers in differentiating tuberculosis pleural effusion

Background and aims

Complement activation is essential for tuberculosis pleural effusion. However, little is known about the value of complement regulatory protein (CD46, CD55, and CD59) in the differential diagnosis of tuberculosis.

Materials and methods

Ninety-nine patients with exudative pleural effusion admitted to Xiangya Hospital of Central South University from June 1, 2021to November 14, 2022 were enrolled. The expression levels of soluble CD46 (sCD46), soluble CD55 (sCD55), and soluble CD59 (sCD59) in pleural effusion were quantified by enzyme-linked immunosorbent assay, and the receiver operating characteristic (ROC) curves were plotted to evaluate the diagnostic and co-diagnostic values.

Results

The ADA level is higher in TPE patients than non-TPE patients. It is well-found that TPE patients had lower levels of sCD46, sCD55, and sCD59 compared with non-TPE patients. Moreover, the expression of sCD46, sCD55, and sCD59 in pleural effusion was negatively correlated with ADA. In addition, the diagnostic efficacy of sCD46, sCD55 and sCD59 was comparable to that of ADA, with 0.896, 0.857, 0.858 and 0.893, respectively. Furthermore, combine detection of sCD46, sCD55, sCD59 and ADA could improve the diagnostic accuracy.

Conclusions

Complement regulatory factors (CD46, CD55, and CD59) were validated by this project to be promising candidate biomarkers for the diagnosis of TPE with high accuracy. The combination of the CD46, CD55, and CD59 and ADA assay exist a better diagnostic value in TPE.

Age : pleural fluid ADA ratio and other indicators for differentiating between tubercular and malignant pleural effusions

Most of pleural effusions are caused by tuberculosis and malignant tumor. Difficult sampling and bacterial sparing nature of these diseases challenge doctors' diagnosis in China. This study aimed to develop a new convenient and effective method for the differentiation of tuberculous and malignant pleural effusion. A prospective cohort study of patients hospitalized with malignant (n = 90) and tuberculous (n = 130) pleural effusions from September 2018 to October 2020 was performed. The diagnostic performance of the age to pleural fluid ADA ratio (age/ADA) and other indicators to distinguish tuberculous and malignant pleural effusions was evaluated by receiver operating characteristic (ROC) curve analysis. The areas under the curve (AUC) of age/ADA and pleural fluid ADA were largest. Age/ADA showed sensitivity and specificity of 81.5% (95%CI 73.8%-87.8%) and 97.8% (95%CI 92.2%-99.7%) respectively. The sensitivity and specificity of pleural fluid ADA were 83.1% (95%CI 75.5%-89.1%) and 93.3% (95%CI 86.1%-97.5%) respectively. The positive likelihood [36.69 (95%CI 9.3-144.8)] of age/ADA was significantly higher than that of pleural fluid ADA [12.46 (95%CI 5.7-27.1)]. The AUCs for Cancer Ratio and Cancer Ratio plus were lower and showed a sensitivity of 80.0% (95%CI 72.1%-86.5%), 80.0% (95%CI 70.2%-87.7%) and a specificity of 81.5% (95%CI 73.8%-87.8%), 80.0% (95%CI 70.2%-87.7%) respectively. Age/ADA has a higher diagnostic accuracy than ADA. Age/ADA is a promising diagnostic index for tuberculous and malignant pleural effusion with high sensitivity and specificity, especially the high positive likelihood ratio. The diagnostic accuracy of Cancer Ratio and Cancer Ratio plus are inferior to those of age/ADA and ADA.

Insight into diagnosis of pleural tuberculosis with special focus on nucleic acid amplification tests

INTRODUCTION

Pleural tuberculosis (TB) is the archetype of extrapulmonary TB (EPTB), which mainly affects the pleural space and leads to exudative pleural effusion. Diagnosis of pleural TB is a difficult task predominantly due to atypical clinical presentations and sparse bacillary load in clinical specimens.

AREA COVERED

We reviewed the current literature on the globally existing conventional/latest modalities for diagnosing pleural TB. Bacteriological examination (smear/culture), tuberculin skin testing/interferon-γ release assays, biochemical testing, imaging and histopathological/cytological examination are the main modalities. Moreover, nucleic acid amplification tests (NAATs), i.e. loop-mediated isothermal amplification, PCR/multiplex-PCR, nested-PCR, real-time PCR and GeneXpert® MTB/RIF are being utilized. Currently, GeneXpert Ultra, Truenat MTB^TM, detection of circulating Mycobacterium tuberculosis (Mtb) cell-free DNA by NAATs, aptamer-linked immobilized sorbent assay and immuno-PCR (I-PCR) have also been exploited.

EXPERT OPINION

Routine tests are not adequate for effective pleural TB diagnosis. The latest molecular/immunological tests as discussed above, and the other tools, i.e. real-time I-PCR/nanoparticle-based I-PCR and identification of Mtb biomarkers within urinary/serum extracellular vesicles being utilized for pulmonary TB and other EPTB types may also be exploited to diagnose pleural TB. Reliable diagnosis and early therapy would reduce the serious complications associated with pleural TB, i.e. TB empyema, pleural fibrosis, etc.

Head-to-head comparison of the efficacy of Xpert MTB/RIF Ultra and Xpert MTB/RIF for the diagnosis of tuberculous pleurisy: A systematic review and meta-analysis

BACKGROUND

The aim of this study was to evaluate the diagnostic accuracy of Xpert MTB/RIF Ultra (Xpert Ultra) and Xpert MTB/RIF (Xpert) for the diagnosis of tuberculous pleurisy (TBP) head-to-head using meta-analysis method.

METHODS

On May 12, 2021, we searched multiple databases for reports that used Xpert Ultra and Xpert for TBP diagnosis head-to-head and screened eligible studies for inclusion. Accuracy of Xpert Ultra and Xpert were compared to that of the composite reference standard (CRS) and culture. When heterogeneity was evident, sources of heterogeneity were explored using subgroup analyses, sensitivity analysis, and meta-regression analyses.

RESULTS

Five articles met the inclusion criteria for meta-analysis. When results from different specimens or different reference standards were reported in the same article, we analyzed them as separate studies. Thus, 6 studies compared Xpert Ultra and Xpert with CRS, 5 studies compared Xpert Ultra and Xpert with culture. Pooled sensitivity and specificity of Xpert Ultra were 52% and 98% compared to CRS, and 82% and 77% compared to culture. Pooled sensitivity and specificity of Xpert were 22% and 99% compared to CRS, and 48% and 94% compared to culture. Significant heterogeneity in sensitivity was observed compared to CRS.

CONCLUSION

The sensitivity of Xpert Ultra was moderate but better than that of the Xpert; however, its specificity was lower. The role of Xpert Ultra and Xpert in the early and rapid diagnosis of TBP was limited.

Paradoxical development of pleural-based masses in patients with pleural tuberculosis during treatment: a clinical observational study in China

Background

To explored the clinical, pathological, and bacteriological characteristics of pleural-based masses occurred during anti-tuberculosis (TB) treatment in patients with pleural TB.

Methods

Patients referred with newly diagnosed pleural TB were prospectively enrolled into the study. Patients were followed up throughout the treatment, and clinical data were recorded. Percutaneous biopsy and surgical tissues from pleural-based masses were examined histologically and samples sent for PCR. Cytokines in the pleural effusions and clinical factors were collected and compared between different patients.

Results

A total of 122 patients with pleural TB were enrolled, and 34.4% (42/122) displayed newly observed pleural-based mass during the treatment. Twelve cases underwent surgical resection at the 12 ± 0.5 months during the treatment course. Based on the surgical observation, 58.3% (7 /12) were located in pleura, 41.7% (5/12) were located in the lung parenchyma. Pathological observations showed that the pleural-based masses were typed as granulomatous inflammation, fibrous hyperplasia and necrosis. Mycobacterium tuberculosis PCR was positive in 57.1% of the cases (24/42). Any first-line anti-TB drug resistance gene mutations were positive in only 9.5% (4/42). Aside from 12 cases who underwent the surgical operation, 86.7% of the patients (26/30) still had a pleural-based mass at the end of 12 months treatment course. Patients with a pleural-based mass were younger, had a thicker pleural, a higher proportion of pleural adhesive, loculated pleural effusion and residual pleural effusion, and a higher level of LDH, ADA and lower glucose in pleural effusion than those without a pleural-based mass occurrence during the treatment (all Pcorr < 0.05).

Conclusions

Pleural-based masses were observed in about one-third of patients with pleural TB. The masses were in the lung or pleura and were divided into three pathological types.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01910-6.

Subsequent Antituberculous Treatment May Not Be Mandatory Among Surgically Resected Culture-Negative Pulmonary Granulomas: A Retrospective Nationwide Multicenter Cohort Study

Background

Histologic diagnosis of granuloma is often considered clinically equivalent to a definite diagnosis of pulmonary tuberculosis (TB) in endemic areas. Optimal management of surgically resected granulomatous inflammation in lung with negative mycobacterial culture results, however, remains unclear.

Methods

From 7 medical institutions in northern, middle, and southern Taiwan between January 2010 and December 2018, patients whose surgically resected pulmonary nodule(s) had histological features suggestive of TB but negative microbiological study results and who received no subsequent anti-TB treatment were identified retrospectively. All patients were followed up for 2 years until death or active TB disease was diagnosed.

Results

A total of 116 patients were enrolled during the study period. Among them, 61 patients (52.6%) were clinically asymptomatic, and 36 (31.0%) patients were immunocompromised. Solitary pulmonary nodule accounted for 44 (39.6%) of all cases. The lung nodules were removed by wedge resection in 95 (81.9%), lobectomy in 17 (14.7%), and segmentectomy in 4 (3.4%) patients. The most common histological feature was granulomatous inflammation (n=116 [100%]), followed by caseous necrosis (n=39 [33.6%]). During follow-up (218.4 patient-years), none of the patients developed active TB.

Conclusions

In patients with surgically resected culture-negative pulmonary granulomas, the incidence rate of subsequent active TB is low. Watchful monitoring along with regular clinical, radiological, and microbiological follow-up, instead of routine anti-TB treatment, may also be a reasonable option.

Pleural Tuberculosis

Pleural tuberculosis (TB) is common and often follows a benign course but may result in serious long-term morbidity. Diagnosis is challenging because of the paucibacillary nature of the condition. Advances in Mycobacterium culture media and PCR-based techniques have increased the yield from mycobacteriologic tests. Surrogate biomarkers perform well in diagnostic accuracy studies but must be interpreted in the context of the pretest probability in the individual patient. Confirming the diagnosis often requires biopsy, which may be acquired through thoracoscopy or image-guided closed pleural biopsy. Treatment is standard anti-TB therapy, with optional drainage and intrapleural fibrinolytics or surgery in complicated cases.

Diagnostic accuracy of adenosine deaminase for pleural tuberculosis in a low prevalence setting: A machine learning approach within a 7-year prospective multi-center study

OBJECTIVE

To analyze the performance of adenosine deaminase in pleural fluid combined with other parameters routinely measured in clinical practice and assisted by machine learning algorithms for the diagnosis of pleural tuberculosis in a low prevalence setting, and secondly, to identify effusions that are non-tuberculous and most likely malignant.

PATIENTS AND METHODS

We prospectively analyzed 230 consecutive patients diagnosed with lymphocytic exudative pleural effusion from March 2013 to June 2020. Diagnosis according to the composite reference standard was achieved in all cases. Pre-test probability of pleural tuberculosis was 3.8% throughout the study period. Parameters included were: levels of adenosine deaminase, pH, glucose, proteins, and lactate dehydrogenase, red and white cell counts and lymphocyte percentage in pleural fluid, as well as age. We tested six different machine learning-based classifiers to categorize the patients. Two different classifications were performed: a) tuberculous/non-tuberculous and b) tuberculous/malignant/other.

RESULTS

Out of a total of 230 patients with pleural effusion included in the study, 124 were diagnosed with malignant effusion and 44 with pleural tuberculosis, while 62 were given other diagnoses. In the tuberculous/non-tuberculous classification, and taking into account the validation predictions, the support vector machine yielded the best result: an AUC of 0.98, accuracy of 97%, sensitivity of 91%, and specificity of 98%, whilst in the tuberculous/malignant/other classification, this type of classifier yielded an overall accuracy of 80%. With this three-class classifier, the same sensitivity and specificity was achieved in the tuberculous/other classification, but it also allowed the correct classification of 90% of malignant cases.

CONCLUSION

The level of adenosine deaminase in pleural fluid together with cell count, other routine biochemical parameters and age, combined with a machine-learning approach, is suitable for the diagnosis of pleural tuberculosis in a low prevalence scenario. Secondly, non-tuberculous effusions that are suspected to be malignant may also be identified with adequate accuracy.

Diagnosis of tuberculous pleural effusions: A review

Tuberculous pleural effusion (TPE) is the second most common presentation of extrapulmonary tuberculosis. The paucibacillary nature of the effusion poses diagnostic challenges. Biomarkers like adenosine deaminase and interferon-γ have some utility for diagnosing TPEs, as do cartridge-based polymerase chain reaction (PCR) methods. When these fluid studies remain indeterminate, pleural biopsies must be performed to confirm the diagnosis. This review article elaborates on the scientific evidence available for various diagnostic tests and presents a practical approach to the diagnosis of TPEs.

Diagnostic Procedures, Diagnoses, and Treatment Outcomes of Patients with Presumptive Tuberculosis Pleural Effusion in Uzbekistan

Tuberculosis (TB) pleural effusion (TPE) is the second most common manifestation of extrapulmonary TB (EPTB), which remains a great diagnostic challenge worldwide. In Uzbekistan, there has been no formal evaluation of the actual practices of diagnosing and treating TPE. Our cohort study therefore aimed to describe the frequency and types of different diagnostic procedures of TPE during 2017–2018 and assess the association of baseline characteristics and establish diagnostic methods with TB treatment outcomes. In total, 187 patients with presumptive TPE were assessed, and 149 had a confirmed diagnosis of TPE (other diagnoses included cancer n = 8, pneumonia n = 17, and 13 cases were unspecified). TB was bacteriologically confirmed in 22 (14.8%), cytologically confirmed in 64 (43.0%), and histologically confirmed in 16 (10.7%) patients. Hepatitis was the only co-morbidity significantly associated with unsuccessful treatment outcomes (RR 4.8; 95%CI: 1.44–15.98, p value 0.011). Multivariable regression analysis showed that drug-resistant TB was independently associated with unsuccessful TB treatment outcome. (RR 3.83; 95%CI: 1.05–14.02, p value 0.04). Multidisciplinary approaches are required to maximize the diagnostic accuracy of TPE and minimize the chances of misdiagnosis. TPE patients with co-infections and those with drug resistance should be more closely monitored to try and ensure successful TB treatment outcomes.

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.

IgG4-related pleural effusion with high adenosine deaminase levels: A case report and literature review

RATIONALE

Levels of pleural fluid adenosine deaminase (ADA), a useful marker for the diagnosis of tuberculous pleurisy, are elevated in some reports of immunoglobulin G4 (IgG4)-related pleural effusion. We describe a patient with IgG4-related pleural effusion who exhibited a high concentration of ADA. Furthermore, we reviewed the literature to compare patients with IgG4-related pleural effusion and tuberculous pleurisy.

PATIENT CONCERNS

A 75-year-old male patient had dyspnea for 1 month with a left pleural effusion that was exudative, lymphocyte dominant. The pleural fluid test results revealed a total protein (TP) concentration of 6.60 g/dl, a lactate dehydrogenase (LDH) level of 383 IU/dl, and an ADA concentration of 54.5 U/L. An interferon gamma release assay showed a negative result.

DIAGNOSES

Histological analysis of the thoracoscopic pleural biopsy revealed lymphoplasmacytic infiltration, with 80 IgG4-positive plasma cells/high-power field, and an IgG4/IgG ratio of approximately 40% to 50%. Other diseases were ruled out based on symptoms, negative autoimmune antigen results, and histopathologic findings. Thus, he was diagnosed with IgG4-related pleural effusion.

INTERVENTIONS

He received 15 mg of prednisolone as therapy.

OUTCOMES

His pleural effusion and symptoms improved gradually within several months, and prednisolone was tapered to 6 mg daily.

LESSONS

It is important to distinguish between IgG4-related pleural effusion and tuberculous pleurisy. Therefore, we compared 22 patients with IgG4-related pleural effusion from PubMed and the Japan Medical Abstracts Society to 40 patients with tuberculous pleurisy at Fukujuji Hospital from January 2017 to May 2019. According to thoracentesis findings, 14 of 18 patients with IgG4-related pleural effusion had high ADA more than 40 U/L. The pleural effusion of patients with IgG4-related pleural effusion showed higher TP levels (P < .001) and lower LDH (P < .001) and ADA levels (P = .002) than those with tuberculous pleurisy. Moreover, the pleural fluid ADA/TP ratio was a good predictor for differentiating IgG4-related pleural effusion and tuberculous pleurisy (area under the receiver operating characteristic curve of 0.909; 95% confidence level: 0.824-0.994).

Value of Cancer Ratio plus and Cancer Ratio Formulation in Distinguishing Malignant Pleural Effusion from Tuberculosis and Parapneumonic Effusion

Background

The aim of our study is to determine the clinical availability accessibility of cancer ratio and cancer ratio plus formulations, previously validated and reported to have clinical value in distinguishing malignant pleural effusion from tuberculosis pleurisy and parapneumonic effusion.

Materials and Methods

Retrospective study of patients hospitalized with Malignant Pleural Effusion (MPE), tuberculosis (TPE) and pararapneumonic effusion (PPE) between 2009 and 2018.

Results

Totally 232 patients, 101(43.5 %) having MPE, 86 (37.1 %) having PPE and 45 (19.4 %) TPE were examined. When compared with each other, "serum LDH / PS Lymphocyte %", "Cancer ratıo" and "Cancer ratıo plus" values were statistically different between the groups (p = 0.021, p <0.001 and p = 0.015, respectively). In multivariate logistic regression analysis, cancer ratio, serum LDH: pleural fluid lymphocyte count ratio was in positive correlation with MPE. The sensitivity and specificity of "cancer ratio", "cancer ratio plus" and "ratio of serum LDH: pleural fluid lymphocyte count" were 84.2 % (95% CI 75.6- 90.7) and 52.7 (95% CI 43.8- 61.5), and 82.2 % (95% CI 73.3- 89.1) and 45.8 (95%CI 37.1- 54.7), 53.5% (95% CI 43.3- 63.5) and 67.2% (95% CI 0.68-0.94) at the cut-off level of >14.25, >28.7, and >636, respectively. When considering only MPE and TPE patients, the specificity of cancer ratıo and cancer ratıo plus increased.

Conclusion

The cancer ratio plus rate (the ratio of "cancer ratio"formulation to the percentage of differential pleural lymphocyte count) was almost the same as the cancer ratio in separating the malignant pleural effusion from the TPE and PPE, while it has better specificity only in differentiating malignant effusions from tuberculosis effusions.

Diagnostics in Pleural Disease

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

Pro-cathepsin D as a diagnostic marker in differentiating malignant from benign pleural effusion: a retrospective cohort study

BACKGROUND

Malignant pleural effusion (MPE) causes substantial symptomatic burden in advanced malignancy. Although pleural fluid cytology is a commonly accepted gold standard of diagnosis, its low diagnostic yield is a challenge for clinicians. The aim of this study was to determine whether pro-cathepsin D can serve as a novel biomarker to discriminate between MPE and benign pleural effusion (BPE).

METHODS

This study included 81 consecutive patients with exudative pleural effusions who had underwent thoracentesis or pleural biopsy. Pleural fluid and serum were collected as a standard procedure for all individuals at the same time. The level of pro-cathepsin D was measured by the sandwich enzyme-linked immunosorbent assay method.

RESULTS

Though there were no significant differences in plasma pro-cathepsin D between the two groups, the level of pleural fluid pro-cathepsin D was significantly higher in the MPE group than the BPE group (0.651 versus 0.590 pg/mL, P = 0.034). The discriminative power of pleural fluid pro-cathepsin D for diagnosing MPE was moderate, with 81% sensitivity and 53% specificity at a pro-cathepsin D cut-off ≥0.596 pg/mL (area under the curve: 0.656). Positive and negative predictive values for MPE were 38 and 89%, respectively, with pro-cathepsin D cut-off value (> 0.596 pg/mL).

CONCLUSIONS

The level of pleural fluid pro-cathepsin D was found to be significantly higher in MPE than in BPE. Although results of this study could not support the sole use of pleural fluid pro-cathepsin D to diagnose MPE, pleural fluid pro-cathepsin D can be added to pre-existing diagnostic methods for ruling-in or ruling-out MPE.

Mycobacterial antigens in pleural fluid mononuclear cells to diagnose pleural tuberculosis in HIV co-infected patients

Background

Extra pulmonary manifestation of tuberculosis (TB) accounts for approximately one-half of TB cases in HIV-infected individuals with pleural TB as the second most common location. Even though mycobacteria are cleared, mycobacterial antigens may persist in infected tissues, causing sustained inflammation and chronicity of the disease. The aim of this study was to explore various mycobacterial antigens in pleural effusions, the impact of HIV infection and CD4+ T-cell depletion on the presence of antigens, and the diagnostic potential of antigens for improved and rapid diagnosis of pleural TB.

Methods

Pleural fluid specimens were collected from patients presenting with clinically suspected pleural TB, and processed routinely for culture, cytology, and adenosine deaminase activity analysis. HIV status and CD4+ T-cell counts were recorded. Pleural fluid mononuclear cells (PFMC) were isolated, and cell smears were stained with acid-fast staining and immunocytochemistry for various mycobacterial antigens. Real-time and nested-PCR were performed. Patients were categorized as pleural TB or non-TB cases using a composite reference standard. Performance of the mycobacterial antigens as diagnostic test was assessed.

Results

A total of 41 patients were enrolled, of which 32 were classified as pleural TB and 9 as non-TB. Thirteen patients had culture confirmed pleural TB, 26 (81%) were HIV-TB co-infected, and 64% had < 100 CD4+ T-cells/microL. Both secreted and cell-wall mycobacterial antigens were detected in PFMC. Lipoarabinomannan (LAM) was the most frequently detected antigen. There was no direct correlation between positive culture and antigens. Cases with low CD4+ T-cell counts had higher bacterial and antigen burden. By combining detection of secreted antigen or LAM, the sensitivity and specificity to diagnose pleural TB was 56 and 78%, respectively, as compared to 41 and 100% for culture, 53 and 89% for nested PCR, and 6 and 100% for real-time PCR.

Conclusion

Mycobacterial antigens were detectable in PFMC from tuberculous pleural effusions, even in cases where viable mycobacteria or bacterial DNA were not always detected. Thus, a combination of secreted antigen and LAM detection by immunocytochemistry may be a complement to acid-fast staining and contribute to rapid and accurate diagnosis of pleural TB.

Relations between serum and pleural fluid biomarkers: a new look of an old concept

Background

Although cytological examination of pleural fluid samples can simply diagnose malignant pleural effusion (MPE), this test has many limitations. There are no established biomarkers for accurate diagnosis of MPE. This study investigated the association of serum lactate dehydrogenase (LDH)/pleural fluid adenosine deaminase (ADA) which is the cancer ratio with MPE together with assessment of the utility of combining pleural lymphocyte counts “cancer ratio plus” in diagnosing MPE and to evaluate the ability of these markers in differentiating MPE from tuberculous pleural effusion (TPE).

Results

This prospective study included 150 individuals who were divided into 3 groups including malignant (n = 94), tuberculous (n = 31), and parapneumonic (n = 25) effusions. It was done during the period from January 2018 to July 2019 to assess the utility of cancer ratio and cancer ratio plus in discrimination between MPE and non-MPE. Serum LDH, cancer ratio, and cancer ratio plus were significantly associated with MPE. Also, age, cancer ratio, and serum LDH to pleural fluid lymphocyte count ratio were positive predictors of MPE. A cutoff level of > 16.02 for the cancer ratio showed sensitivity and specificity of 61% (95% CI 0.5002–0.7056) and 96% (95% CI 0.8769–0.9956) respectively. At this cutoff, the positive likelihood ratio was 16.99, while the negative likelihood ratio was 0.41.

Conclusion

Cancer ratio was found to be more accurate than cancer ratio plus and serum LDH to pleural fluid lymphocyte count ratio in identifying MPE especially in patients with negative pleural fluid cytology.

The diagnostic effect of sequential detection of ADA screening and T-SPOT assay in pleural effusion patients

Purpose: To evaluate the diagnostic effect of sequential detection of Adenosine deaminase (ADA) screening and T-SPOT assay on tuberculosis (TB) pleurisy in pleural effusion patients. Materials and methods: 248 pleural effusion patients (172 TB and 76 non-TB) were retrospectively analyzed in the study. The concentrations of ADA and lactate dehydrogenase (LDH) were measured in pleural fluids and serum samples of the patients. T-SPOTT assays were performed in pleural fluids. The relationship between ADA, T-SPOT and the occurrence of TB pleurisy was evaluated using logistic regression analysis. Results: The level of pleural ADA and positive rate of T-SPOT were all higher in TB pleurisy group than non-TB pleurisy group (p < .001). The positive rate of T-SPOT detection reached 98.83% in the TB pleurisy group while only 40.7% in non-TB pleurisy group (p < .001). Additionally, 8 patients (4.65%) in the TB pleurisy group showed the level of pleurisy ADA exceeded 40 IU/L while only one patient (1.31%) in the non-TB pleurisy group. Conclusion: The sequential detection of ADA screening and T-SPOT assay was found to be an accurate and rapid method for identifying TB pleurisy from pleural effusion, which would promote effective treatment.

Predominance of Th1 Immune Response in Pleural Effusion of Patients with Tuberculosis among Other Exudative Etiologies

Pleural tuberculosis (PlTB), a common form of extrapulmonary TB, remains a challenge in the diagnosis among many causes of pleural effusion. We recently reported that the combinatorial analysis of interferon gamma (IFN-γ), IFN-γ-inducible protein 10 (IP-10), and adenosine deaminase (ADA) from the pleural microenvironment was useful to distinguish pleural effusion caused by TB (microbiologically confirmed or not) among other etiologies. In this cross-sectional cohort study, a set of inflammatory mediators was quantified in blood and pleural fluid (PF) from exudative pleural effusion cases, including PlTB (n = 27) and non-PlTB (nTB) (n = 25) patients. The levels of interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17A, IFN-γ, tumor necrosis factor (TNF), IP-10, transforming growth factor β1 (TGF-β), and ADA were determined using cytometric bead assay, enzyme-linked immunosorbent assay (ELISA), or biochemical tests. IFN-γ, IP-10, TNF, TGF-β, and ADA quantified in PF showed significantly higher concentrations in PlTB patients than in nTB patients. When blood and PF were compared, significantly higher concentrations of IL-6 and IL-10 in PF were identified in both groups. TGF-β, solely, showed significantly increased levels in PF and blood from PlTB patients when both clinical specimens were compared to those from nTB patients. Principal-component analysis (PCA) revealed a T helper type 1 (Th1) pattern attributed mainly to higher levels of IP-10, IFN-γ, TGF-β, and TNF in the pleural cavity, which was distinct between PlTB and nTB. In conclusion, our findings showed a predominantly cellular immune response in PF from TB cases, rather than other causes of exudative effusion commonly considered in the differential diagnosis of PlTB.

Advances in pleural effusion diagnostics

Introduction: Pleural effusion is a common clinical problem. Yet, in a significant proportion of patients (~20%), the cause of pleural effusion remains unknown. Understanding the diagnostic value of pleural fluid tests is crucial for the development of accurate diagnostic models.Areas covered: This paper provides an overview of latest advances in the diagnosis of pleural effusion based on the best evidence available.Expert opinion: For pleural fluid tests to have a good diagnostic value, it is necessary that data obtained from clinical history, physical examination, and radiological studies are correctly interpreted. Thoracentesis and pleural biopsy should always be performed under image guidance to improve its diagnostic sensitivity and prevent complications. Nucleic acid amplification tests, pleural tissue cultures, and collection of pleural fluid in blood culture bottles improve the diagnostic yield of pleural fluid cultures. Although undiagnosed pleural effusions generally have a favorable prognosis, follow-up is recommended to prevent the development of a malignant pleural effusion.

Pleural tuberculosis

A 35-year-old woman with previously untreated latent tuberculosis was admitted to the hospital for management of a right-sided empyema. After a prolonged hospitalization and several interventions, including chest tubes, bronchoscopy with bronchoalveolar lavage, and a video-assisted thoracoscopic surgery, positive acid-fast bacilli cultures on the initial thoracentesis ultimately led to the diagnosis of pleural tuberculosis. This case highlights the importance of utilizing a combination of diagnostic tests to diagnose pleural tuberculosis, especially in the setting of a negative pleural adenosine deaminase level.

Tuberculous pleural effusion

Tuberculous effusion is a common disease entity with a spectrum of presentations from a largely benign effusion, which resolves completely, to a complicated effusion with loculations, pleural thickening and even frank empyema, all of which may have a lasting effect on lung function. The pathogenesis is a combination of true pleural infection and an effusive hypersensitivity reaction, compartmentalized within the pleural space. Diagnostic thoracentesis with thorough pleural fluid analysis including biomarkers such as adenosine deaminase and gamma interferon achieves high accuracy in the correct clinical context. Definitive diagnosis may require invasive procedures to demonstrate histological evidence of caseating granulomas or microbiological evidence of the organism on smear or culture. Drug resistance is an emerging problem that requires vigilance and extra effort to acquire a complete drug sensitivity profile for each tuberculous effusion treated. Nucleic acid amplification tests such as Xpert MTB/RIF can be invaluable in this instance; however, the yield is low in pleural fluid. Treatment consists of standard anti-tuberculous therapy or a guideline-based individualized regimen in the case of drug resistance. There is low-quality evidence that suggests possible benefit from corticosteroids; however, they are not currently recommended due to concomitant increased risk of adverse effects. Small studies report some short- and long-term benefit from interventions such as therapeutic thoracentesis, intrapleural fibrinolytics and surgery but many questions remain to be answered.

Tuberculous pleural effusion: diagnosis & management

Background: Tuberculosis (TB) is the world's leading cause of death from infectious disease. The World Health Organization (WHO) recognized 6.3 million new TB cases in 2017, 16% corresponding to extrapulmonary forms; pleural tuberculosis (PT) is the most common extrapulmonary form in adults. PT diagnosis is often challenging because the scarcity of bacilli in pleural fluid (PF), sometimes requiring invasive procedures to obtain pleural tissue for histological, microbiological or molecular examination. In regions of medium and high disease prevalence, adenosine deaminase (ADA), interferon gamma (IFN-γ) and interleukin 27 (IL-27) dosages are useful to establish presumptive diagnosis in patients with compatible clinical/radiological picture who present with lymphocytic pleural effusion. PT treatment is similar to the pulmonary TB treatment regimen recommended by WHO. Area covered: In this update, we present a PT review, including epidemiology, pathogenesis, clinical features, diagnosis, and therapy. Expert opinion: There is no PF test alone accurate for PT diagnosis, despite the evolution in clinical laboratory. ADA, IFN-γ and IL-27 are valuable laboratory biomarkers; however, IFN-γ and IL-27 are quite expensive. Molecular tests present low sensitivity in PF, being useful for diagnostic confirmation. Multidrug therapy remains the PT treatment choice. Advancing research in immunotherapy may bring benefits to PT patients.

Correlation between videothoracoscopy and biopsy in patients with pleural effusion and suspected tuberculosis in a high complexity military hospital

Background: In the diagnostic process of pleural tuberculosis, the findings from video-assisted thoracoscopy (VATS) can be highly suggestive for the diagnosis of infection.Methods: We reviewed VATS records between the years 2012 to 2016 of patients over 16 years of age with pleural effusion and suspected pleural tuberculosis. Symptoms, macroscopic and chemical characteristics of the fluid, surgical descriptions and visual diagnosis of the surgeon were recorded and were compared with the histopathology.Results: 106 patients were selected, most of them men (71.7%), of whom approximately half were active military (51.3%). The predominant symptoms were dyspnea, pleuritic pain, fever and evolution time greater than 15 days (94.3%, 80.2%, 50% and 46,2%, respectively). These symptoms, in turn, were present more frequently in pleural tuberculosis patients than in non-tuberculosis patients. The fluid was mostly turbid yellow (44%) and lymphocytic cellularity exudate (77.4%). The VATS findings in patients with confirmed TBC included nodules (96.9%), adhesions (87.5%) and thickening (78.1%). The diagnosis made by the surgeon in relation to the histopathological diagnosis showed a sensitivity of 88.6% and a specificity of 98.4%.Conclusion: There are highly suggestive characteristics of the macroscopic report of VATS that would allow a quicker diagnosis of pleural tuberculosis.

Potential biomarkers for antidiastole of tuberculous and malignant pleural effusion by proteome analysis

AIM

To investigate novel potential biomarkers for antidiastole of tuberculous pleural effusion (TPE) from malignant pleural effusion (MPE).

MATERIALS & METHODS

iTRAQTM-coupled LC-MS/MS were applied to analyze the proteome of TPE and MPE samples. The candidate proteins were verified by enzyme-linked immunosorbent assay.

RESULTS

A total of 432 differential proteins were identified. Enzyme-linked immunosorbent assay revealed significantly higher levels of fibronectin (FN) and cathepsin G (CTSG) in MPE than in TPE, but lower levels of leukotriene-A4 hydrolase (LTA4H). The receiver operator characteristic values were 0.285 for FN, 0.64 for LTA4H, 0.337 for CTSG and 0.793 for a combination of these candidate markers.

CONCLUSION

FN, LTA4H and CTSG were identified as potential biomarkers to differentiate TPE from MPE and their combination exhibited higher diagnostic capacity.

Pleural infection: a closer look at the etiopathogenesis, microbiology and role of antibiotics

INTRODUCTION

Pleural infection is a condition that continues to pose a significant challenge to respiratory physicians. We hypothesize that the main barriers to progress include limited understanding of the etiopathogenesis, microbiology,and role of antibiotics in the pleural space. Areas covered: PubMed was searched for articles related to adult pleural infection using the terms 'pleural infection', 'empyema' and 'parapneumonic'. The search focused on relevant literature within the last 10 years, with any older citations used only to display context or lack of progress. Tuberculous pleural infection was excluded. We chose to give specific attention to the etiopathogenesis of pleural infection, including recent advances in diagnostics and biomarkers. We discuss our understanding of the pleural microbiome and rationalize the current use of antibiotics in treating this condition. Expert commentary: Understanding of key events in the development of this condition remains limited. The microbiology is unique compared to the lung, and highly variable. Higher culture yields from pleural biopsy may add new insights into the etiopathogenesis. There is little evidence into achievable effective antibiotic concentration within the pleura. Research into issues including the relevance of biofilm formation and significance of pleural thickening is necessary for treatment progress.

The Performance of Pleural Fluid T-SPOT.TB Assay for Diagnosing Tuberculous Pleurisy in China: A Two-Center Prospective Cohort Study

The performance of T-SPOT.TB (T-SPOT) assay in diagnosing pleural tuberculosis (plTB) is inconsistent. In this study, we compared the performance of peripheral blood (PB) and pleural fluid (PF) T-SPOT assay in diagnosing plTB. Between July 2017 and March 2018, 218 and 210 suspected plTB patients were prospectively enrolled from Wuhan (training) and Guangzhou (validation) cohort, respectively. PB T-SPOT, PF T-SPOT, and other conventional tests were simultaneously performed. Our data showed the performance of PB T-SPOT in diagnosing plTB was limited, especially with low sensitivity. However, the results of early secreted antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10) in PF T-SPOT were significantly increased compared with those in PB T-SPOT in plTB patients. If using 76 as the cutoff value of MAX (the larger of ESAT-6 and CFP-10) in Wuhan cohort, the sensitivity and specificity of PF T-SPOT to diagnose plTB were 89.76 and 96.70%, respectively. The diagnostic accuracy of PF T-SPOT was better than other routine tests such as pathogen detection methods and biochemical markers. The diagnostic accuracy of PF T-SPOT in Guangzhou cohort was similar to that in Wuhan cohort, with a sensitivity and specificity of 91.07 and 94.90%, respectively. Furthermore, CD4⁺ T cells were more activated in PF compared with PB, and the frequency of mycobacterium tuberculosis-specific CD4⁺ T cells in PF was significantly higher than that in PB in plTB patients. In conclusion, the performance of PF T-SPOT is obviously better than PB T-SPOT or other laboratory tests, which suggests that PF T-SPOT assay has been of great value in the diagnosis of pleural tuberculosis.

Pleural tuberculosis: A concise clinical review

Tuberculosis (TB) is the leading infectious cause of death worldwide, and the commonest cause of death in people living with HIV. Globally, pleural TB remains one of the most frequent causes of pleural exudates, particularly in TB-endemic areas and in the HIV positive population. Most TB pleural effusions are exudates with high adenosine deaminase (ADA), lymphocyte-rich, straw-coloured and free flowing, with a low yield on mycobacterial culture. TB pleurisy can also present as loculated neutrophil-predominant effusions which mimic parapneumonic effusions. Rarely, they can present as frank TB empyema, containing an abundance of mycobacteria. Up to 80% of patients have parenchymal involvement on chest imaging. The diagnosis is simple if M. tuberculosis is detected in sputum, pleural fluid or biopsy specimens, and the recent advent of liquid medium culture techniques has increased the microbiological yield dramatically. Where the prevalence of TB is high the presence of a lymphocyte-predominant exudate with a high ADA has a positive predictive value of 98%. In low prevalence areas, the absence of an elevated ADA and lymphocyte predominance makes TB very unlikely, and pleural biopsy should be performed to confirm the diagnosis. Pleural biopsy for liquid culture and susceptibility testing must also be considered where the prevalence of drug resistant TB is high. Treatment regimens are identical to those administered for pulmonary TB. Initial pleural drainage may have a role in symptom relief and in hastening the resolution of the effusion. Surgical intervention may be required in loculated effusions and empyemas.

Clinical significance of Glasgow Prognostic Score in patients with tuberculous pleurisy

Background

The Glasgow Prognostic Score (GPS) reflects the host systemic inflammatory response and is a validated, independent prognostic factor for various malignancies. We investigated the clinical significance of the GPS in patients with tuberculosis (TB) pleurisy, focusing on treatment outcomes including paradoxical response (PR).

Methods

This was a retrospective study performed between January 2010 and December 2015 in two referral and university hospitals in South Korea, with intermediate incidences of TB. In all, 462 patients with TB pleurisy were registered in the study. The patients were classified into three groups based on GPS score, as follows: (I) GPS of 2, elevated CRP level (>1.0 mg/dL) and hypoalbuminemia (<3.5 g/dL); (II) GPS of 1, elevated CRP level or hypoalbuminemia; and (III) GPS of 0, neither elevated CRP level nor hypoalbuminemia.

Results

A total of 367 patients with TB pleurisy were finally included. PR occurred in 102 (27.8%) patients after a mean of 75 days following initiation of anti-TB treatment. The proportion of PR occurrence was significantly lower in the GPS 2 group (P=0.007). Successful treatment outcomes including cure and completion were also significantly lower in the GPS 2 group (P=0.001), while all-cause mortality and TB-specific mortality were higher in the GPS 2 group (P=0.001 and <0.001, respectively). Old age over than 65 years old was an independent predicting factor for high mortality and lower PR occurrence. However, the TB relapse rate was not different among the three GPS groups.

Conclusions

Higher GPS value and elderly age were identified as prognostic factors for poor outcomes in TB pleurisy and as predicting factors for lower PR occurrence. More prospective studies are needed to clarify the utility of GPS in patients with TB pleurisy.

Pleural tuberculosis: a key differential diagnosis for pleural thickening, even without obvious risk factors for tuberculosis in a low incidence setting

We report the case of a 64-year-old woman, presenting with pleuritic chest pain and weight loss. She had a previous history of breast malignancy and no clear risk factors for tuberculosis (TB). Initial investigations showed a right-sided pleural effusion and pleural thickening suggestive of malignancy, which would have been in keeping with the clinical presentation. Initial pleural biopsy showed features suggestive of possible TB infection, though no growth on cultures. A repeat biopsy was negative on initial microscopy, but was culture positive for Mycobacterium tuberculosis, also identifying isoniazid resistance. This case highlights that TB remains an important differential even in the absence of classical risk factors, and illustrates the diagnostic challenges it poses. It also highlights the value of culture positivity in identification of drug resistance and facilitation of appropriate treatment.

Ultrasound-Guided versus Thoracoscopic Pleural Biopsy for Diagnosing Tuberculous Pleurisy Following Inconclusive Thoracentesis: A Randomized, Controlled Trial

BACKGROUND Traditional diagnostic methods for tuberculosis (TB) cannot be reliably applied to tuberculous pleurisy. Therefore, this prospective, randomized, controlled trial was performed to compare the diagnostic sensitivity and safety of ultrasound-guided cutting-needle pleural biopsy versus thoracoscopic pleural biopsy in patients suspected of tuberculous pleurisy following inconclusive thoracentesis. MATERIAL AND METHODS A total of 196 adult patients with acid-fast bacillus (AFB)-negative exudative pleural effusions clinically suspected of tuberculous pleurisy were recruited. Enrollees were randomized into 2 cohorts: ultrasound-guided cutting-needle pleural biopsy (n=96) or thoracoscopic pleural biopsy (n=96). The overall diagnostic yields, diagnostic sensitivities for tuberculous pleurisy, and post-procedural complications for both cohorts were statistically compared. RESULTS Ultrasound-guided pleural biopsy displayed an overall diagnostic yield of 83%, while thorascopic pleural biopsy displayed a similar overall diagnostic yield of 86% (χ²=1.88, df=1, p=0.17). There were 127 patients conclusively diagnosed with tuberculous pleurisy, resulting in a tuberculous pleurisy prevalence of 65% in this patient population (66% in the ultrasound cohort vs. 63% in the thoracoscopy cohort; p>0.05). Ultrasound-guided pleural biopsy displayed a sensitivity of 82% in detecting tuberculous pleurisy, while thorascopic pleural biopsy displayed a similar sensitivity of 90% (χ²=1.05, df=1, p=0.30). The sensitivities of these 2 modalities did not significantly differ based on the degree of pleural thickening (p>0.05). Post-procedural complications were minor. CONCLUSIONS Ultrasound-guided and thoracoscopic pleural biopsy both display strong (>80%) but statistically similar overall diagnostic yields for diagnosing pleural effusions following inconclusive thoracentesis. Both modalities also display strong (>80%) but statistically similar sensitivities in detecting tuberculous pleurisy.