Pleural tuberculosis: A concise clinical review

Diagnostic scoring systems for tuberculous pleural effusion in patients with lymphocyte-predominant exudative pleural profile: A development study

Background

Diagnosing tuberculous pleural effusion (TPE) in patients presenting with Lymphocyte-Predominant Exudative pleural effusion (LPE) is challenging, due to the poor clinical utility of TB culture. Adenosine deaminase (ADA) has been recommended for diagnosis, but its high cost and limited availability hinder its clinical utility. We aim to develop diagnostic prediction tools for Thai patients with LPE in scenarios where pleural fluid ADA is available but yields negative results and in situations where pleural fluid ADA is not available.

Methods

Two diagnostic prediction tools were developed using retrospective data from patients with LPE at Surin Hospital. Model 1 is for ADA-negative results, and Model 2 is for situations where pleural fluid ADA testing is unavailable. The models were derived using multivariable logistic regression and presented as two clinical scoring systems: round-up and count scoring. The score cut-point that achieves a positive predictive value (PPV) comparable to the post-test probability of a pleural fluid ADA at a cut-point of 40 U/L was used as a threshold for initiating anti-TB treatment.

Results

A total of 359 patients were eligible for analysis, with 166 diagnosed with TPE and 193 diagnosed with non-TPE. Age <40 years, fever, pleural fluid protein ≥5 g/dL, male gender, pleural fluid color, and pleural fluid ADA ≥20 U/L were identified as final predictors. Both models demonstrated excellent discriminative ability (AuROC: 0.85 to 0.89). The round-up scoring demonstrated PPV above 90% at cut-off points of 4 and 4.5, while the count scoring achieved cut-off points of 3 and 4 for Model 1 (Lex-2P2A) and Model 2 (Lex-2P-MAC), respectively.

Conclusion

These diagnostic tools offer valuable assistance in differentiating between TPE and non-TPE in LPE patients with negative pleural fluid ADA (Lex-2P2A) and in settings where pleural fluid ADA testing is not available (Lex-2P-MAC). Implementing these diagnostic scores may have the potential to improve TPE diagnosis and facilitate prompt initiation of treatment.

Diagnostic flowchart for tuberculous pleurisy, pleural infection, and malignant pleural effusion

BACKGROUND

Several markers for the diagnosis of pleural effusion have been reported; however, a comprehensive evaluation using those markers has not been performed. Therefore, this study aimed to develop a diagnostic flowchart for tuberculous pleurisy, pleural infection, malignant pleural effusion, and other diseases by using these markers.

METHODS

We retrospectively collected data from 174 patients with tuberculous pleurisy, 215 patients with pleural infection other than tuberculous pleurisy, 360 patients with malignant pleural effusion, and 209 patients with other diseases at Fukujuji Hospital from January 2012 to October 2022. The diagnostic flowchart for four diseases was developed by using several previously reported markers.

RESULTS

The flowchart was developed by including seven markers: pleural ADA ≥40 IU/L, pleural fluid LDH <825 IU/L, pleural fluid ADA/TP < 14, neutrophil predominance or cell degeneration, peripheral blood WBC ≥9200/μL or serum CRP ≥12 mg/dL, pleural amylase ≥75 U/L, and the presence of pneumothorax according to the algorithm of a decision tree. The accuracy ratio of the flowchart was 71.7 % for the diagnosis of the four diseases, with 79.3 % sensitivity and 75.4 % positive predictive value (PPV) for tuberculosis pleurisy, 75.8 % sensitivity and 83.2 % PPV for pleural infection, 88.6 % sensitivity and 68.8 % PPV for malignant pleural effusion, and 33.0 % sensitivity and 60.0 % PPV for other diseases in the flowchart. The misdiagnosis ratios were 4.6 % for tuberculosis pleurisy, 6.8 % for pleural infection, and 8.3 % for malignant pleural effusion.

CONCLUSION

This study developed a useful diagnostic flowchart for tuberculous pleurisy, pleural infection, malignant pleural effusion, and other diseases.

LDH/ADA ratio in pleural fluid for the diagnosis of infectious pleurisy

Pleural effusion (PE) is a common medical concern, often requiring thoracentesis for a definitive diagnosis. An elevated pleural fluid adenosine deaminase (ADA) may indicate tuberculosis, but this is not always the case. This study aimed to evaluate the accuracy of biomarkers determined in pleural fluid and propose a new diagnostic strategy for PE in patients with high levels of ADA in pleural fluid. This retrospective analysis studied patients with PE who received thoracentesis for the first time with an ADA level of > 33 U/L in the pleural fluid analysis at two tertiary hospitals from March 2019 to March 2023. Demographic and clinical data, as well as pleural fluid biomarkers and their ratios, were studied and compared between different PE groups, and a decision tree was developed. During the study period, 259 patients were enrolled, with four different types of PE: parapneumonic (PPE) 155, tuberculosis (TPE) 41, malignant (MPE) 50, and miscellaneous 13. Biomarkers and their ratios performed well in the differential diagnosis of PE, with the LDH/ADA ratio distinguishing between PPE and non-PPE with sensitivity and specificity of 98.06% and 98.08%, respectively. The combination of LDH/ADA ratio, ADA, and mononuclear cell percentage was identified as important factors for creating a decision tree with an overall accuracy of 89.96%. The pleural fluid LDH/ADA ratio was a useful diagnostic for distinguishing PPE from non-PPE, and a decision tree with an accuracy of 89.96% was created to differentiate the four forms of PE in clinical situations.

Diagnostic accuracy and microbial profiles of tuberculous pleurisy: a comparative study of metagenomic next generation sequencing and GeneXpert Mycobacterium tuberculosis

Introduction

There is a clinical challenge in diagnosing tuberculous pleurisy accurately and promptly, highlighting the urgent need for a rapid and sensitive diagnostic method. This study aimed to evaluate the diagnostic accuracy of metagenomic next-generation sequencing (mNGS) and GeneXpert Mycobacterium tuberculosis (MTB) for identifying tuberculous pleurisy and analyzing the microbial profiles of both tuberculous and non-tuberculous pleural effusions.

Methods

The study enrolled 31 patients with suspected tuberculous pleurisy, of which 15 were confirmed to have tuberculous pleurisy and subsequently allocated to the tuberculous pleurisy group (TP group), while the remaining 16 individuals were assigned to the non-tuberculous pleurisy group (NTP group). mNGS and GeneXpert MTB were performed on pleural effusion samples, and the diagnostic accuracy of both tests was compared. We employed established formulas to compute crucial indicators, including sensitivity, specificity, missed diagnosis rate, misdiagnosed rate, positive predictive value (PPV), and negative predictive value (NPV).

Results

The results showed that both tests had high specificity (100%) and positive predictive value (100%) for detecting tuberculous pleurisy, along with comparable sensitivity (46.67% for mNGS and 40.0% for GeneXpert MTB). Further analysis of the combined efficacy of mNGS and GeneXpert MTB showed that the combined test had a sensitivity of 66.67% and a specificity of 100%. mNGS analysis revealed that MTB was detected in 7 out of 15 patients with tuberculous pleural effusions, while non-tuberculous pleural effusions were associated with a diverse range of microbial genera and species. The most frequently detected genera at the microbial genus level in the NTP group were Microbacterium spp. (6/16), Prevotella spp. (5/16), and Campylobacter spp. (5/16).

Discussion

These findings suggest that mNGS and GeneXpert MTB are useful diagnostic tools for identifying patients with tuberculous pleurisy, and mNGS can provide valuable insights into the microbial profiles of both tuberculous and non-tuberculous pleural effusions.

The safety and efficacy of decortication for stage III drug-resistant tuberculous empyema

OBJECTIVES

The goal of this study was to evaluate the safety and efficacy of decortication for stage III drug-resistant tuberculous empyema (TE).

METHODS

We analysed all patients with stage III TE who underwent decortication between March 2015 and October 2019 at Wuhan Pulmonary Hospital. The patients were divided into 2 groups according to drug-susceptibility testing of bronchoscopy lavage fluid, pleural effusion and tissue specimens, including a drug-resistant group and a drug-sensitive group. We collected and compared the preoperative, perioperative and postoperative data from the 2 groups to evaluate the safety and efficacy of decortication for stage III drug-resistant TE.

RESULTS

In total, 135 cases met the inclusion criteria and were enrolled, including 30 cases in the drug-resistant group and 105 cases in the drug-sensitive group. No deaths were recorded for the entire study population. Compared to the drug-sensitive group, the drug-resistant group had longer operation times (259.8 ± 78.4 min vs 187.2 ± 56.0 min, P = 0.00), a larger volume of intraoperative blood loss [300 (200,400) ml vs 200 (130, 300) ml, P = 0.00] and a higher intraoperative transfusion rate (5/30, 16.7% vs 4/105, 3.8%, P = 0.04). The rate of complications was significantly higher in the drug-resistant group (23; 76.7%) than in the drug-sensitive group (53; 50.5%) (P = 0.01). Recurrence was not reported in any of the patients. Twenty-three (76.7%) patients in the drug-resistant group and 90 (85.7%) patients in the drug-sensitive group recovered to an "excellent" level, and 3 cases in each group recovered to a "poor" level; there was no significant difference between the 2 groups in surgical effects (P = 0.21).

CONCLUSIONS

Decortication is a safe, effective and feasible option for patients with stage III drug-resistant TE, although the operation is difficult and risky.

Early Use of Intrapleural Tissue Plasminogen Activator and Dornase Alfa in Loculated Pleural Effusion Due to Mycobacterium Tuberculosis

Tuberculosis is a highly infectious respiratory disease due to Mycobacterium tuberculosis (MTb). The most common manifestation of MTb is pulmonary tuberculosis, but some patients can present with extrapulmonary manifestations as their initial presentation. Tuberculous pleurisy and pleural effusion are among the most common extrapulmonary manifestations of MTb. The treatment of pleural MTb is the same as the treatment for pulmonary disease, with a four-drug regimen with rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) under directly observed therapy (DOT). Drainage of the pleural effusion is usually not recommended in tuberculosis pleural effusion. We present a case of a complex, loculated pleural effusion due to MTb in an otherwise healthy middle-aged male who responded rapidly and completely to an early, short course of intrapleural tissue plasminogen activator and dornase alfa (TPA/DNase) therapy.

Pyopneumothorax Secondary to Pulmonary Tuberculosis Superadded by Congenital Factor XIII Deficiency: A Case Report

Pyopneumothorax is a rare complication of pulmonary tuberculosis, contributing significantly to morbidity and mortality. Additionally, factor XIII deficiency, a rare bleeding disorder, may pose a diagnostic challenge due to normal results in routine coagulation tests. We present the case of an 18-year-old boy who presented with a history of left-sided pyopneumothorax secondary to drug-sensitive Mycobacterium tuberculosis, complicated by congenital factor XIII deficiency. After three months of intercostal drainage placement, the patient developed severe anemia and bleeding tendencies, necessitating a referral to clinical hematology. Genetic testing revealed factor XIII deficiency. This case highlights the complicated interplay between tuberculosis-related complications and a coexisting genetic disorder, highlighting the importance of comprehensive clinical assessment and multidisciplinary management.

Primary Effusion Lymphoma-like Lymphoma Mimicking Tuberculous Pleural Effusion: Three Case Reports and a Literature Review

Primary effusion lymphoma-like lymphoma (PEL-LL) is a rare lymphoma, localized in the body cavity without detectable tumor masses. Tuberculous pleural effusion is a form of extra pulmonary tuberculous. We herein report three cases of PEL-LL in patients with a history of pulmonary tuberculosis. Despite the presentation with lymphocyte predominance and high levels of adenosine deaminase, a notable characteristic of tuberculous pleural effusion, the patients were ultimately diagnosed with PEL-LL. Pleural fluid laboratory tests yield similar results for PEL-LL and tuberculous pleural effusion; therefore, cytological and immunophenotyping examinations are useful for their differential diagnosis and the determination of treatment.

Open decortication for patients presenting with stage III tuberculous empyema with low density lines on CT imaging

To explore the influence of CT findings on the optimal timing of open decorticationin patients with stage III tuberculous empyema. A total of 80 patients with stage III tuberculous empyema who had undergone open decortications were recruited; 44 patients had chest CT findings indicating low-density lines, while 36 patients did not show this imaging finding. Demographic data, perioperative data and preoperative and postoperative chest CT images were collected. In the low-density line group, the duration of disease (P = 0.0030) and the preoperative anti-tuberculosis time (P = 0.0016) were longer than those of the group without low-density lines, and the ESR (P = 0.0218), CRP (P = 0.0027) and leukocyte count (P = 0.0339) were lower in the low-density line group. Additionally, in the median operative time (P = 0.0003), intraoperative blood loss (P < 0.0001), volume of catheter drainage during 48 h after operation (P = 0.0067), chest tube duration (P < 0.0001), and length of hospital stay (P = 0.0154) were significantly lower in the low-density line group than in the group without low-density lines. A total of 88.64% of participants in the low-density line group showed hyperplasia with hyaline degeneration in pathological examination, which was observed only in 41.67% of patients without low-density lines. In addition, gaseous necrosis was considerably higher in patients without a low-density line (P = 0.004), while the low-density line group had a higher rate of treatment success (P < 0.05). Patients with stage III tuberculous empyema presenting with low-density lines around the thickened fibrous pleural rind on preoperative CT imaging may be good candidates for open decortication.

Clinical manifestations and immune response to tuberculosis

Tuberculosis is a far-reaching, high-impact disease. It is among the top ten causes of death worldwide caused by a single infectious agent; 1.6 million tuberculosis-related deaths were reported in 2021 and it has been estimated that a third of the world's population are carriers of the tuberculosis bacillus but do not develop active disease. Several authors have attributed this to hosts' differential immune response in which cellular and humoral components are involved, along with cytokines and chemokines. Ascertaining the relationship between TB development's clinical manifestations and an immune response should increase understanding of tuberculosis pathophysiological and immunological mechanisms and correlating such material with protection against Mycobacterium tuberculosis. Tuberculosis continues to be a major public health problem globally. Mortality rates have not decreased significantly; rather, they are increasing. This review has thus been aimed at deepening knowledge regarding tuberculosis by examining published material related to an immune response against Mycobacterium tuberculosis, mycobacterial evasion mechanisms regarding such response and the relationship between pulmonary and extrapulmonary clinical manifestations induced by this bacterium which are related to inflammation associated with tuberculosis dissemination through different routes.

Differentiation of malignant from benign pleural effusions based on artificial intelligence

INTRODUCTION

This study aimed to construct artificial intelligence models based on thoracic CT images to perform segmentation and classification of benign pleural effusion (BPE) and malignant pleural effusion (MPE).

METHODS

A total of 918 patients with pleural effusion were initially included, with 607 randomly selected cases used as the training cohort and the other 311 as the internal testing cohort; another independent external testing cohort with 362 cases was used. We developed a pleural effusion segmentation model (M1) by combining 3D spatially weighted U-Net with 2D classical U-Net. Then, a classification model (M2) was built to identify BPE and MPE using a CT volume and its 3D pleural effusion mask as inputs.

RESULTS

The average Dice similarity coefficient, Jaccard coefficient, precision, sensitivity, Hausdorff distance 95% (HD95) and average surface distance indicators in M1 were 87.6±5.0%, 82.2±6.2%, 99.0±1.0%, 83.0±6.6%, 6.9±3.8 and 1.6±1.1, respectively, which were better than those of the 3D U-Net and 3D spatially weighted U-Net. Regarding M2, the area under the receiver operating characteristic curve, sensitivity and specificity obtained with volume concat masks as input were 0.842 (95% CI 0.801 to 0.878), 89.4% (95% CI 84.4% to 93.2%) and 65.1% (95% CI 57.3% to 72.3%) in the external testing cohort. These performance metrics were significantly improved compared with those for the other input patterns.

CONCLUSIONS

We applied a deep learning model to the segmentation of pleural effusions, and the model showed encouraging performance in the differential diagnosis of BPE and MPE.

Drug transdermal delivery by electrophonophoresis can increase the concentration of rifampicin in the pleural effusion of patients with tuberculous pleurisy but has no effect on the concentration of rifampicin in plasma

BACKGROUND

Electrophonophoresis (EP) has been widely used in various clinical fields. The purpose of this study was to evaluate the dermal permeability of rifampicin (RIF) in patients with tuberculous pleurisy assisted by EP and to verify the clinical application of this percutaneous drug delivery system in the treatment of tuberculous pleurisy, verify the system's influencing factors, and determine whether plasma drug concentration was increased.

METHOD

Patients were given oral isoniazid 0.3-0.4 g, rifampicin 0.45-0.60 g, pyrazinamide 1.0-1.5 g and ethambutol 0.75 g according to their body weight once a day. After 5 days of anti-tuberculosis treatment, 3 ml of rifampicin was delivered transdermally with EP. Pleural effusion and peripheral blood samples in patients were collected at and after dosing. The drug concentration in the samples was determined by high-performance liquid chromatography.

RESULT

The median plasma concentration (interquartile ranges) of RIF in 32 patients was 8.80 (6.65, 13.14) μg/ml before RIF transdermal injection plus EP and decreased to 8.09 (5.58, 11.82) μg/ml after 30 min of RIF transdermal injection plus EP. The RIF concentration in pleural effusion was higher than that before RIF-transdermal plus EP. In patients who received RIF via EP transdermal administration, the concentration of the drug at the local site was statistically higher than the concentration at the local site prior to penetration. However, no such enhancement was observed in plasma after transdermal administration of RIF.

CONCLUSION

EP can effectively increase the concentration of rifampicin in the pleural effusion of tuberculous pleurisy and has no effect on the circulating plasma concentration. The increased concentration of the drug in the lesion helps to destroy the bacteria.

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

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

Drug Resistance and Molecular Characteristics of Mycobacterium tuberculosis: A Single Center Experience

In recent years, the incidence of tuberculosis (TB) and mortality caused by the disease have been decreasing. However, the number of drug-resistant tuberculosis patients is increasing rapidly year by year. Here, a total of 380 Mycobacterium tuberculosis (MTB)-positive formalin-fixed and paraffin-embedded tissue (FFPE) specimens diagnosed in the Department of Pathology of the Eighth Medical Center, Chinese PLA General Hospital were collected. Among 380 cases of MTB, 85 (22.37%) were susceptible to four anti-TB drugs and the remaining 295 (77.63%) were resistant to one or more drugs. The rate of MDR-TB was higher in previously treated cases (52.53%) than in new cases [(36.65%), p  <  0.05]. Of previously treated cases, the rate of drug resistance was higher in females than in males (p  <  0.05). Among specimens obtained from males, the rate of drug resistance was higher in new cases than in previously treated cases (p  <  0.05). Of mutation in drug resistance-related genes, the majority (53/380, 13.95%) of rpoB gene carried the D516V mutation, and 13.42% (51/380) featured mutations in both the katG and inhA genes. Among the total specimens, 18.68% (71/380) carried the 88 M mutation in the rpsL gene, and the embB gene focused on the 306 M2 mutation with a mutation rate of 19.74%. Among the resistant INH, the mutation rate of −15 M was higher in resistance to more than one drug than in monodrug-resistant (p  <  0.05). In conclusion, the drug resistance of MTB is still very severe and the timely detection of drug resistance is conducive to the precise treatment of TB.

Left pleural effusion in a young woman with genital tuberculosis

Disseminated tuberculosis is a rare form of tuberculosis that can cause severe illness if diagnosed and treated late. We present the case of a young Senegalese woman who had a miscarriage due to a pelvic inflammatory disease, followed by the development of a left pleural effusion. Despite laparoscopic findings and a salpinx biopsy that revealed necrotizing granulomas, only microbiological examinations of pleural biopsies revealed the final diagnosis of disseminated, drug-sensitive tuberculosis.

Pleural tuberculosis: experiences from two centers in Brazil

OBJECTIVE

This study aimed to describe the clinical and laboratory findings of patients diagnosed with pleural tuberculosis at two hospitals in southern Brazil.

METHODS

Patients aged < 18 years were evaluated retrospectively. The patients' medical and epidemiological history, tuberculin skin test results, radiological and pathological findings, and pleural fluid analysis results were retrieved.

RESULTS

Ninety-two patients with pleural tuberculosis were identified. The mean age was 10.9 years old. Twenty-one percent were children aged six years or less. The most common symptoms were fever (88%), cough (72%), and chest pain (70%). Unilateral pleural effusion was observed in 96% of the cases. Lymphocyte predominance was found in 90% of the pleural fluid samples. The adenosine deaminase activity of the pleural fluid was greater than 40 U/L in 85% of patients. A diagnosis of community-acquired pneumonia with antibiotic prescriptions was observed in 76% of the study population.

CONCLUSIONS

Tuberculosis etiology must be considered in unilateral pleural effusion in a child with contact with a case of tuberculosis. Pleural fluid biomarkers contribute to the diagnosis of pleural tuberculosis in children and adolescents.

Clinical Value of Pleural Effusion and Serum MMP-3 and CYFRA21-1 Combined with ADA in Differential Diagnosis of Pleural Exudative Effusion

Objective

The aim of the study is to investigate the clinical value of matrix metalloproteinases-3 (MMP-3) and cytokeratin 19 fragment antigen 21-1 (CYFRA21-1) combined with adenosine deaminase (ADA) in pleural effusion and serum in benign and malignant pleural exudative effusion (PEE).

Methods

A total of 119 adult patients with PEE admitted in our hospital from May 2018 to October 2021 were selected. According to the patient's condition, the patients were divided into the benign group (n = 75) and the malignant group (n = 44). The levels of MMP-3, CYFRA21-1, and ADA in pleural effusion and serum were detected. The receiver operating characteristic (ROC) curve was used to analyze the individual and combined predictive value of MMP-3, CYFRA21-1, and ADA levels.

Results

In the malignant group, the pleural effusion and serum MMP-3 and CYFRA21-1 levels were higher than those in the benign group and the ADA levels were lower than those in the benign group (P < 0.05). In the malignant group, the positive detection rate of pleural effusion and serum MMP-3 and CYFRA21-1 was higher than that in the benign group and the positive detection rate of pleural effusion and serum ADA were lower than that in the benign group (P < 0.05). The AUC of pleural effusion MMP-3, serum MMP-3 and the combination of them in the diagnosis of PEE were 0.764, 0.722 and 0.810, respectively. The AUC of pleural effusion CYFRA21-1 and serum CYFRA21-1 and combination of them in the diagnosis of PEE were 0.776, 0.748 and 0.822, respectively. The AUC of pleural effusion ADA, serum ADA and their combination in differential diagnosis of PEE were 0.762, 0.737 and 0.836, respectively. The AUC of pleural effusion and serum of MMP-3 and CYFRA21-1 combined with ADA for differential diagnosis of PEE was 0.923.

Conclusions

The diagnostic efficacy of MMP-3 combined with CYFRA21-1 and ADA in pleural effusion and serum for benign and malignant PEE are better than single index, which has certain clinical values for the selection of early intervention scheme for PEE patients.

Rapid Molecular Diagnosis of Extra-Pulmonary Tuberculosis by Xpert/RIF Ultra

Rapid detection of Mycobacterium tuberculosis complex and determination of drug resistance are essential for early diagnosis and treatment of tuberculosis (TB). Xpert MTB/RIF Ultra (Xpert Ultra), a molecular test that can simultaneously identify M. tuberculosis complex and resistance to rifampicin directly on clinical samples, is currently used. Xpert Ultra represents a helpful tool for rapid pulmonary TB diagnosis, especially in patients with paucibacillary infection. The aim of this review is to provide an overview of the diagnostic performance of Xpert Ultra in detection of extra-pulmonary tuberculosis.

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.

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.

Rapid Detection of Mycobacterium tuberculosis in Pleural Fluid Using Resuscitation-Promoting Factor-Based Thin Layer Agar Culture Method

Background

Pleural tuberculous is difficult to diagnose. Culture is still considered the gold standard, especially in resource-limited settings where quick, cheap, and easy techniques are needed. The aim of the study was to evaluate resuscitation-promoting factors (Rpfs)-based thin layer agar (TLA) culture method for quick detection of Mycobacterium tuberculosis in pleural fluid.

Methods

Patients with suspected pleural TB were enrolled prospectively in our hospital, pleural fluid of all patients were collected, stained with Ziehl–Neelsen for acid-fast bacilli (AFB), cultured on Rpfs-TLA, TLA, and Löwenstein–Jensen (LJ) medium, and identified according to recommended procedures.

Results

A total of 137 suspected pleural TB were enrolled and categorized, including 103 pleural TB (49 confirmed and 54 probable pleural TB) and 34 non-TBP patients. The sensitivity of Rpfs-TLA for total pleural TB was 43.7% (34.5∼53.3%), higher than that of TLA 29.1% (21.2∼38.5%) and LJ 26.2% (18.7∼35.5%) (p < 0.01), and all specificity was 100% in the diagnosis of pleural TB. Median time to detection of a positive culture was 11.8 days (95% CI 10.4∼13.4) for Rpfs-TLA, 21.0 days (95% CI 19.1∼22.9) for TLA, and 30.5 days (95% CI 28.5∼32.5) for LJ (p < 0.001).

Conclusion

Rpfs-TLA is an accurate, rapid, cheap, and easy culture method, which makes it promising for use in clinical laboratories.

Diagnostic role of internal mammary lymph node involvement in tuberculous pleurisy: a multicenter study

BACKGROUND AND OBJECTIVES

Diagnosis of tuberculous pleurisy (TP) may be challenging and it often requires pleural biopsy. A tool able to increase pre-test probability of TP may be helpful to guide diagnostic work-up and enlargement of internal mammary lymph node (IMLN) has been suggested to play a potential role. The aim of the present investigation was to assess role of IMLN involvement in TP in a multi-centric case-control study, by comparing its prevalence and test performance to those observed in patients with infectious, non-tuberculous pleurisy (NTIP), and in controls free from respiratory diseases (CP).

METHODS

A total of 419 patients, from 14 Pulmonology Units across Italy were enrolled (127 patients affected by TP, 163 affected by NTIP and 129 CP). Prevalence, accuracy and predictive values of ipsilateral IMLN involvement between cases and control groups were assessed, as well as concordance between chest computed tomography (CT scan) and thoracic ultrasound (TUS) measurements.

RESULTS

The prevalence of ipsilateral IMLN involvement in TP was significantly higher than that observed in NTIP and CP groups (respectively 77.2%, 39.3% and 14.7%). Results on test performance, stratified by age, revealed a high positive predictive value in patients aged ≤50 years, while a high negative predictive value in patients aged >50 years. The comparison between CT scan and ultrasound showed moderate agreement (Kappa=0.502).

CONCLUSIONS

Evaluation of IMLN involvement plays a relevant role in assessing the pre-test probability of TP. Considering the increasing global prevalence of mycobacterial infections, a tool able to guide diagnostic work-up of suspected TP is crucial, especially where local sources are limited.

Hemorrhagic pleural effusion in Indonesian male with pulmonary tuberculosis: A rare case

Background

Patients with hemorrhagic pleural effusion who live in tuberculosis endemic areas are recommended to perform adenosine deaminase (ADA) test.

Case presentation

A Javanese 22-year-old male complained of shortness of breath and cough with phlegm for 1 week, and worsened 3 days before being admitted to the hospital. The X-ray results showed pleural effusion, and hemorrhagic pleural effusion examination showed an increase in lymphocytes (60.2%), lactate dehydrogenase/LDH (2624 U/L), and cell count (4584 cells/mm³), and the ADA test obtained 49 IU/L. The water-sealed drainage (WSD) was installed and first-line anti-tuberculosis drug (ATD) was given for 1 month. After showing improvement in the first month, the first-line ATD was continued until 6 months.

Discussion

Patients with hemorrhage pleural effusion who live in tuberculosis endemic areas are recommended to perform differential diagnosis of hemorrhage pleural effusion and pulmonary tuberculosis. The use of the first-line ATD in hemorrhagic pleural effusion and pulmonary tuberculosis needs to be evaluated in the first month to detect improvement, otherwise, the medication is stopped and other investigations are carried out.

Conclusion

Successful management of hemorrhagic pleural effusion and pulmonary tuberculosis depends on early diagnosis.

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The diagnosis of tuberculosis pleural effusion is considered in endemic tuberculosis.

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Management of hemorrhagic tuberculosis pleural effusion includes chest tube and anti-tuberculosis drug (ATD).

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Hemorrhagic tuberculosis pleural effusion can be confirmed by the ADA test.

Accuracy of Xpert MTB/RIF assay for the diagnosis of tuberculous pleural effusion

Background

Tuberculosis poses a severe threat to human health. At present, compared with the traditional diagnostic methods for tuberculosis pleural effusion, such as Löwenstein–Jensen culture, pleural biopsy, and Ziehl–Neelsen smear microscopy, Xpert MTB/RIF was regarded as an emerging technology for its efficiency. The Xpert MTB/RIF accuracy for tuberculous pleural effusion diagnosis was evaluated in this systematic study.

Materials and methods

We searched the relevant literature published before January 2021 in PubMed, Cochrane, EMBASE, and Web of Science databases. Utilizing Review Manager 5.3 software, the quality of the included literature was evaluated based on the Quality Assessment of Diagnostic Accuracy Studies criteria. Sensitivity, specificity, and the summary receiver operating characteristic curves were plotted and analyzed with Metadisc 1.40 software. We used Stata 12.0 software to evaluate the publication bias of this study.

Results

Eighteen articles were identified in total. The sensitivity of Xpert MTB/RIF in the pleural effusion was 0.24, and specificity was 1.00, respectively. The area under the summary receiver operating characteristic curve was 0.9737, which indicated that the overall accuracy of the Xpert MTB/RIF was high. In addition, based on the Deeks funnel plot, no publication bias of the study was found.

Conclusion

Xpert MTB/RIF is a rapid method with high specificity but relatively low sensitivity for detecting Mycobacterium tuberculosis in pleural effusion. Its less sensitivity made it difficult to be used clinically, but the high specificity suggests that it can be used as a specific diagnostic method for tuberculous pleural effusion.

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.

Risk factors associated with postoperative respiratory failure in tuberculous empyema patients

Our objective was to identify independent risk factors for predicting which patients in the Chinese population would likely develop respiratory failure.A descriptive analysis was conducted of demographic and clinical data of patients with tuberculous empyema (TE) admitted to the Beijing Chest Hospital, Capital Medical University between January 2001 and January 2020. Risk factors associated with postsurgical respiratory failure in TE patients were identified based on results of analyses based on univariable and multivariable logistic regression models.A total of 139 TE patients who underwent surgical treatment in the Beijing Chest Hospital, Capital Medical University from January 2001 to January 2020 were enrolled in this study. Cases included 109 male and 30 female patients, with an overall mean age (range 17-73) of 39.3 years. Of 139 TE patients, 26 (18.7%) experienced respiratory failure after surgery. Among significant risk factors for postsurgical respiratory failure, intraoperative blood loss volume greater than 1000 mL had the highest odds ratio value of 6.452. In addition, a pathologic preoperative pulmonary function test result showing a high partial pressure of carbon dioxide level was an independent risk factor for respiratory failure. Moreover, the presence of tuberculosis lesions in the contralateral lung was another significant risk factor for respiratory failure, as determined using multivariate analysis.Respiratory failure is a predominant complication experienced by TE patients undergoing surgery. High intraoperative blood loss, high preoperative high partial pressure of carbon dioxide level, and tuberculosis lesion(s) in the contralateral lung of TE patients were associated with increased risk of postoperative respiratory failure.

Performance of the quantification of adenosine deaminase and determination of the lactate dehydrogenase/adenosine deaminase ratio for the diagnosis of pleural tuberculosis in children and adolescents

Objective:

To evaluate the accuracy of determining the adenosine deaminase (ADA) level, the 2’-deoxyadenosine/ADA ratio, and the LDH/ADA ratio in pleural fluid for the diagnosis of pleural tuberculosis (PT) in children and adolescents.

Methods:

This was a retrospective cross-sectional study conducted at a tertiary hospital in a high-tuberculosis-incidence area, between 2001 and 2018. All patients with ADA in pleural fluid and a confirmed diagnosis of PT (cPT) or parapneumonic effusion (PPE) were included.

Results:

The cPT and PPE groups comprised 25 and 68 individuals, respectively. At a cutoff of 40 U/L, ADA measurement showed the following: sensitivity, 88%; specificity, 31%; positive predictive value (PPV), 32%; negative predictive value (NPV), 88%; and overall accuracy, 46%. The best cutoffs were an ADA level of 125 U/L, a 2’-deoxyadenosine/ADA ratio of 0.5, and an LDH/ADA ratio of 8.3, with AUC of 0.67, 0.75, and 0.82, respectively. The sensitivity, specificity, PPV, NPV, and overall accuracy of the 125 U/L ADA cutoff were 84%, 65%, 47%, 92%, and 70%, respectively, compared with 79%, 79%, 59%, 91%, and 79%, respectively, for the 8.3 LDH/ADA ratio cutoff. Changing the LDH/ADA ratio cutoff to 3.0 increased the specificity to 98%.

Conclusions:

The ADA level and the 2’-deoxyadenosine/ADA ratio are not good biomarkers for the diagnosis of PT in pediatric patients. Determination of the LDH/ADA ratio provides the best overall accuracy for the diagnosis of PT in such patients.

The Intrapleural Bridge Connection is One of the Reasons for Unknown Localized Pleural Adhesion

Background

Simple signs of local pleural adhesion are often found in people during a physical examination. In the present study, we aimed to clarify whether the merely localized pleural adhesion was just caused by previous pleural inflammation or physiological variation.

Materials and Methods

Chest X-ray image materials were collected to analyze the incidence of simple pleural adhesions. Moreover, the causes of these simple pleural adhesions were further analyzed using thoracoscopy under direct vision and biopsy data.

Results

In all 2218 chest X-ray images, 68 cases were found to have pleural lesions (3.07%), including 15 cases of localized pleural adhesion only. Subsequently, we analyzed the characteristics of 70 cases of pleural lesions using thoracoscopy. In two lung cancer patients with pleural metastasis, we found an unusual pleural junction. This connective strip was smooth and free of inflammation, resembling the normal pleura.

Conclusion

Some of these purely localized pleural adhesions might be attributed to previous inflammation. However, there was still at least a possibility that there must be a physiological pleural junction, which could be the cause of the purely localized pleural adhesion shown in the chest radiograph.

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.

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

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

[Association of borderline tuberculoid leprosy and tuberculosis: A case report and review of the literature]

INTRODUCTION

In metropolitan France, nearly 20 new cases of leprosy are diagnosed each year. The incidence of tuberculosis in France is 8/100,000 inhabitants and there are very few accounts of association of these two mycobacteria. Herein we report a case of co-infection with borderline tuberculoid (BT) leprosy and disseminated tuberculosis diagnosed in metropolitan France.

PATIENTS AND METHODS

A male subject presented with diffuse painless infiltrated erythematous plaques. The biopsy revealed perisudoral and perineural lymphohistiocytic epithelioid cell granuloma as well as acid-alcohol-fast bacilli on Ziehl staining. PCR was positive for Mycobacterium leprae, confirming the diagnosis of leprosy in the BT form. The staging examination revealed predominantly lymphocytic left pleural effusion, right-central necrotic adenopathy without histological granuloma, negative screening for BK, a positive QuantiFERON-TB™ test, and a positive intradermal tuberculin reaction. The clinical and radiological results militated in favour of disseminated tuberculosis. Combined therapy (rifampicin, isoniazid, ethambutol and pyrazinamide) together with clofazimine resulted in regression of both cutaneous and extra-cutaneous lesions. This rare co-infection combines leprosy, often present for several years, and tuberculosis (usually pulmonary) of subsequent onset. The pathophysiological hypothesis is that of cross-immunity (with anti-TB immunity protecting against subsequent leprosy and vice versa), supported by the inverse correlation of the two levels of prevalence and by the protection afforded by tuberculosis vaccination. In most cases, treatment for TB and leprosy improves both diseases. Patients presenting leprosy should be screened for latent tuberculosis in order to avoid reactivation, particularly in cases where corticosteroid treatment is being given.

Uniportal Thoracoscopic Decortication for Stage III Tuberculous Empyema With Severe Rib Crowding

BACKGROUND

This study explored the safety and feasibility of uniportal video-assisted thoracoscopic (VATS) decortication in patients presenting with stage III tuberculous empyema with severe rib crowding.

METHODS

From August 2017 to January /2019, 33 patients with stage III tuberculous empyema and severe rib crowding underwent uniportal VATS decortication with partial rib resection and the use of a customized periosteal stripper. Preoperative and postoperative chest computed tomography (CT) imaging and pulmonary function testing were analyzed to evaluate the clinical significance of certain imaging findings and surgical efficacy.

RESULTS

There was 1 conversion to open thoracotomy. Median operative time was 3.5 hours (range, 2.1-4.5 hours) and the median blood loss was 500 mL (range, 250-1000 mL). There were no perioperative mortalities. The incidence of prolonged air leaks (>5 days) was 81.8%. Median postoperative hospital stay was 4 days (range, 4-5 days). All patients were discharged with 2 chest tubes, and median duration drainage was 39 days (range, 30-60 days). The presence of a low-density line between the parietal fibrous pleural rind and chest wall was demonstrated on chest CT in 13 patients. Intraoperative blood loss was considerably lower in these patients compared with those without this imaging finding. Follow-up was complete in all patients over a median of 8 months (range, 6-11.5 months). All patients recovered well and achieved notable improvement in pulmonary function.

CONCLUSIONS

Uniportal VATS decortication is safe and effective. Patients presenting with a low-density line around the thickened fibrous pleural rind on preoperative chest CT scan may be good candidates.

Pleural Tuberculosis: A Febrile Presentation Without Respiratory Symptoms

Tuberculosis (TB) is one of the largest public health crises globally, with pleural TB comprising a large portion of cases. It has a significantly minimal presence within the United States in comparison to the rest of the world. Awareness of its presence and acumen on diagnostics and treatment are essential. Conventional tests are often time consuming, and do not always yield accurate results. We present the case of a patient presenting with fevers but no cough, who eventually found to have large pleural effusion and concluded to have pleural TB without pulmonary parenchymal involvement. He then showed measurable improvement with empiric treatment.

Use of Xpert MTB/RIF and Xpert Ultra in extrapulmonary tuberculosis

INTRODUCTION

Tuberculosis (TB) remains a major global health burden. There still remains a large gap between the notified and estimated incident cases. Extrapulmonary (EP) TB represents 15% of all TB cases and the diagnosis is more challenging due to the paucity of the organism. Smear microscopy is often insensitive and culture methods are prolonged. With the introduction of Xpert MTB/RIF and more recently Xpert Ultra, this has changed TB diagnostics by providing a rapid accessible platform to diagnose TB and identify rifampicin resistance within 2 h.

AREAS COVERED

The diagnostic accuracy and the clinical role of Xpert MTB/RIF and Xpert Ultra in the different forms of EPTB.

EXPERT OPINION

Whilst significant advances have been made in TB diagnostics, there is still a need to optimize the diagnostic yield of Xpert MTB/RIF and Xpert Ultra in EPTB samples. Research is needed to facilitate standardization and optimal preparation of samples as well as understanding the role of Xpert MTB/RIF and Xpert Ultra in different burden settings. Alongside the current GeneXpert platform, the launch of rapid second-line drug resistance polymerase chain reactions and whole genome sequencing may help tackle the global health burden with a more comprehensive diagnostic approach and appropriate treatment.

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.

Mycobacterium tuberculosis Dissemination Plays a Critical Role in Pathogenesis

Mycobacterium tuberculosis is primarily a respiratory pathogen. However, 15% of infections worldwide occur at extrapulmonary sites causing additional complications for diagnosis and treatment of the disease. In addition, dissemination of M. tuberculosis out of the lungs is thought to be more than just a rare event leading to extrapulmonary tuberculosis, but rather a prerequisite step that occurs during all infections, producing secondary lesions that can become latent or productive. In this review we will cover the clinical range of extrapulmonary infections and the process of dissemination including evidence from both historical medical literature and animal experiments for dissemination and subsequent reseeding of the lungs through the lymphatic and circulatory systems. While the mechanisms of M. tuberculosis dissemination are not fully understood, we will discuss the various models that have been proposed to address how this process may occur and summarize the bacterial virulence factors that facilitate M. tuberculosis dissemination.

Extrapulmonary tuberculosis

Extrapulmonary tuberculosis can be confused with other pathologies because of the variety of symptoms it generates according to the affected organ. So, extrapulmonary tuberculosis must always be taken into account by medical staff within the differential diagnosis. In this paper, a review of the literature on extrapulmonary tuberculosis is carried out with emphasis on the most frequently affected organs.

Pleural fluid ADA activity in tuberculous pleurisy can be low in elderly, critically ill patients with multi-organ failure

Background

Adenosine deaminase (ADA) activity is typically elevated in patients with tuberculous pleural effusion (TPE), but low ADA has occasionally been reported in patients with TPE. The characteristics of these patients are not well-known, and erroneous exclusion of the possibility of TPE can result in a delayed diagnosis. This study investigated the characteristics of patients with TPE who had low ADA activity.

Methods

We retrospectively reviewed patients with microbiologically or pathologically confirmed TPE between 2012 to 2018 in a tertiary hospital in South Korea. Patients were categorised into two groups: high ADA (≥40 IU/L) and low ADA (< 40 IU/L). Clinical characteristics and Sequential Organ Failure Assessment (SOFA) scores were compared between groups.

Results

A total of 192 patients with TPE were included; 36 (18.8%) had ADA < 40 IU/L with a mean ADA activity level of 20.9 (±9.2) IU/L. Patients with low ADA were older (75.3 vs. 62.0 years, p < 0.001) and had a lower mean lymphocyte percentage (47.6% vs. 69.9%, p < 0.001) than patients with high ADA. Patients in the low ADA group had a significantly higher mean SOFA score (2.31 vs. 0.68, p < 0.001), and patients with organ dysfunction were significantly more common in the low ADA group (p < 0.001). Patients with 2 or ≥ 3 organ dysfunctions constituted 19.4 and 13.9% of the patients in the low ADA group, whereas they constituted 7.1 and 1.3% of the patients in the high ADA group (p < 0.001). Multivariate logistic regression analyses showed that older age (odds ratio = 1.030, 95% confidence interval 1.002–1.060, p = 0.038) and a higher SOFA score (odds ratio = 1.598, 95% confidence interval 1.239–2.060, p < 0.001) were significantly associated with low ADA activity in patients with TPE.

Conclusions

ADA activity can be low in patients with TPE who are elderly, critically ill, and exhibit multiorgan failure. Low ADA activity cannot completely exclude the diagnosis of TPE, and physicians should exercise caution when interpreting pleural fluid exams.

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.

[CME: Extrapulmonary Tuberculosis]

CME: Extrapulmonary Tuberculosis Abstract. While tuberculosis mostly manifests as pulmonary infection, a dissemination in any extrapulmonary organ is possible. Extrapulmonary tuberculosis mostly affects lymph nodes, pleura and bones. Patients with immunosuppressive conditions such as an HIV co-infection or immunosuppressive therapies like TNF-alpha-inhibitors have a higher risk of a dissemination of tuberculosis. Diagnosis of extrapulmonary tuberculosis is difficult, as microbiological testing mostly requires invasive procedures to obtain a sample for direct proof of tuberculosis by microscopy, culture, molecular methods (e.g. Xpert® MTB/RIF) or histology. Treatment follows guidelines of pulmonary tuberculosis with a two-month regimen consisting of four drugs (rifampicin, isoniazide, pyrazinamide and ethambuthol), followed by a four-month therapy with two drugs (rifampicin and isoniazide). Duration of therapy is extended in tuberculous meningitis to one year and in a skeletal dissemination up to six to nine months. Corticosteroids are recommended in cerebral and pericardial tuberculosis.

The use of real-time polymerase chain reaction and an adenosine deaminase assay for diagnosing pleural tuberculosis

Background

The diagnosis of pleural tuberculosis remains a challenge, because the most widely used conventional diagnostic tools are unable to rapidly detect Mycobacterium tuberculosis in pleural fluid with sufficient sensitivity.

Objectives

The aim of this study was to evaluate the usefulness of an adenosine deaminase assay and real-time polymerase chain reaction (qPCR) in diagnosing pleural tuberculosis.

Methods

One hundred and five consecutive pleural fluid specimens collected between August 2008 and March 2009 were assessed. Among the 105 specimens, 50 (48%) were unconfirmed tuberculosis cases, 21 (20%) were confirmed tuberculosis cases and 34 (32%) were non-tuberculosis cases (controls). Real-time PCR was performed using the Light Cycler Mycobacterium detection kit according to the manufacturer‘s instructions (Roche Diagnostics). An adenosine deaminase assay was carried out using a commercial colorimetric assay kit as a user-defined method on a Beckman DxC 600 Synchron analyser.

Results

The sensitivity of the qPCR was 67% and specificity was 100%. The sensitivity of the adenosine deaminase assay was 80% and specificity was 94%.

Conclusion

The findings show that the adenosine deaminase assay had higher sensitivity than qPCR. Real-time PCR had 100% specificity, thus a combination of the two methods may be useful for the diagnosis of pleural tuberculosis.

Ultrasound elastography: a novel tool for the differential diagnosis of pleural effusion

INTRODUCTION

Traditional thoracic ultrasound (TUS) is often the initial tool used to help diagnose malignant pleural effusion (MPE). Ultrasound elastography, a relatively new technique, has been used to differentiate malignant disease from benign disease by evaluating tissue "stiffness". However, no studies evaluating the efficacy of ultrasound elastography for diagnosing MPE are available. We assessed the value of ultrasound elsatography for diagnosing MPE prospectively.

METHODS

All 244 enrolled patients were divided into a development set and a validation set in chronological order. The cut-off elasticity index was established using a receiver operating characteristic curve constructed from the continuous data of the patients in the development set. The diagnostic performance of ultrasound elastography was compared with that of TUS in the validation set.

RESULTS

In the development set, the mean elasticity index (47.25 kPa) was the optimal cut-off. In the validation set, pleural ultrasound elastography had a sensitivity of 83.64%, a specificity of 90.67%, a positive predictive value of 86.79%, a negative predictive value of 88.31%, a positive likelihood ratio of 8.96 and a negative likelihood ratio of 0.18 for diagnosing MPE. The sensitivity of ultrasound elastography was significantly higher (p=0.006) than that of TUS (60%).

CONCLUSION

Pleural ultrasound elastography is a better technique than TUS for differentiating MPE from benign pleural disease.

Long-term efficacy of 6-month therapy with isoniazid and rifampin compared with isoniazid, rifampin, and pyrazinamide treatment for pleural tuberculosis

Research into anti-tuberculosis treatment has mainly focused on pulmonary tuberculosis (TB), with few studies on pleural-TB. The aim of the study is to compare the long-term efficacy of a 6-month treatment regimen with isoniazid and rifampicin (6HR) with treatment regimen of isoniazid, rifampicin, and pyrazinamide (6HR2Z) for pleural-TB. A case-control study of 200 HIV-negative patients with pleural-TB prospectively followed in our TB-unit from 1995 to 2018. The primary resistance to isoniazid is < 4% in our geographic area. Pleural-TB diagnosis was based on a positive culture for M. tuberculosis (84 patients), presence of caseating granulomas in pleural biopsy (28), or characteristics of pleural fluid (88). A comparative study of demographic and clinical characteristics between the treatment groups was carried out. Out of the 200 patients followed, (112 males, 88 females; mean age 32.9 ± 18.4 years), 99 patients were treated with 6HR regimen and 101 with 6HR2Z. The groups were comparable, except the 6HR2Z had larger size of pleural effusion. All patients completed the treatment. The group treated with 6HR presented fewer adverse effects (15.3%) than 6HR2Z group (33%), p = 0.005, and lower frequency of severe hepatic toxicity (5% vs 10.9%). Four patients died from causes other than TB during treatment with 6HR2Z, and all other patients were cured during a monitoring period for 8.4 years (IQRs, 3.3-14.3). Six patients in 6HR and 10 in 6HR2Z developed residual pachypleuritis. 6HR is as effective as 6HR2Z treatment for pleural-TB, with fewer adverse effects.