Combined use of pleural adenosine deaminase with lymphocyte/neutrophil ratio. Increased specificity for the diagnosis of tuberculous pleuritis

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.

The Clinical Experience of Mycobacterial Culture Yield of Pleural Tissue by Pleuroscopic Pleural Biopsy among Tuberculous Pleurisy Patients

Background and Objectives: Tuberculous pleurisy is a common extrapulmonary TB that poses a health threat. However, diagnosis of TB pleurisy is challenging because of the low positivity rate of pleural effusion mycobacterial culture and difficulty in retrieval of optimal pleural tissue. This study aimed to investigate the efficacy of mycobacterial culture from pleural tissue, obtained by forceps biopsy through medical pleuroscopy, in the diagnosis of TB pleurisy. Materials and Methods: This study retrospectively enrolled 68 TB pleurisy patients. Among them, 46 patients received semi-rigid pleuroscopy from April 2016 to March 2021 in a tertiary hospital. We analyzed the mycobacterial culture from pleural tissue obtained by forceps biopsy. Results: The average age of the study participants was 62.8 years, and 64.7% of them were men. In the pleuroscopic group, the sensitivity of positive Mycobacterium tuberculosis (M. TB) cultures for sputum, pleural effusion, and pleural tissue were 35.7% (15/42), 34.8% (16/46), and 78.3% (18/23), respectively. High sensitivities of M. TB culture from pleural tissue were up to 94.4% and 91.7% when pleural characteristic patterns showed adhesion lesions and both adhesion lesions and presence of micronodules, respectively. Conclusions: M. TB culture from pleural tissue should be considered a routine test when facing unknown pleural effusion during pleuroscopic examination.

Classification of pleural effusions using deep learning visual models: contrastive-loss

Blood and fluid analysis is extensively used for classifying the etiology of pleural effusion. However, most studies focused on determining the presence of a disease. This study classified pleural effusion etiology employing deep learning models by applying contrastive-loss. Patients with pleural effusion who underwent thoracentesis between 2009 and 2019 at the Asan Medical Center were analyzed. Five different models for categorizing the etiology of pleural effusion were compared. The performance metrics were top-1 accuracy, top-2 accuracy, and micro-and weighted-AUROC. UMAP and t-SNE were used to visualize the contrastive-loss model’s embedding space. Although the 5 models displayed similar performance in the validation set, the contrastive-loss model showed the highest accuracy in the extra-validation set. Additionally, the accuracy and micro-AUROC of the contrastive-loss model were 81.7% and 0.942 in the validation set, and 66.2% and 0.867 in the extra-validation set. Furthermore, the embedding space visualization in the contrastive-loss model exhibited typical and atypical effusion results by comparing the true and false positives of the rule-based criteria. Therefore, classifying the etiology of pleural effusion was achievable using the contrastive-loss model. Conclusively, visualization of the contrastive-loss model will provide clinicians with valuable insights for etiology diagnosis by differentiating between typical and atypical disease types.

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.

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.

Diagnosis of tuberculosis pleurisy with three endoscopic features via pleuroscopy

Background:

Tuberculosis (TB) is a constant threat even with a worldwide active public health campaign. Diagnosis of TB pleurisy is challenging in the case of pleural effusion of unknown origin after aspiration analysis. The study was designed to demonstrate a simple image interpretation technique to differentiate TB pleurisy from non-TB pleurisy using semi-rigid pleuroscopy.

Methods:

The study retrospectively enrolled 117 patients who underwent semi-rigid pleuroscopy from April 2016 to August 2018 in a tertiary hospital. We analyzed the possibility of TB pleurisy using three simple pleuroscopic images via semi-rigid pleuroscopy.

Results:

Among 117 patients, 28 patients (23.9%) were diagnosed with TB pleurisy. Sago-like nodules/micronodules, adhesion, and discrete distribution were noted in 20 (71.4%), 20 (71.4%), and 19 (67.9%) patients with TB pleurisy, respectively. Sago-like nodules/micronodules, adhesion, and discrete distribution were noted in six (6.7%), 37 (41.6%), and no (0.0%) patients with non-TB pleurisy, respectively. The positive and negative predictive values of any two out of three pleuroscopic patterns for TB pleurisy were 100.0% and 93.7%, respectively.

Conclusions:

A high positive predictive value for TB pleurisy was demonstrated by the presence of any two out of the three characteristic features. Absence of all three features had an excellent negative predictive value for TB pleurisy. Our diagnostic criteria reconfirm that pleuroscopic images can be used as predictors for TB pleurisy in patients with undiagnosed pleural effusion.

The reviews of this paper are available via the supplementary material section.

The Utility of Pleural Fluid Lactate Dehydrogenase to Adenosine Deaminase Ratio in Pleural Tuberculosis

In high-burden settings, the diagnosis of pleural tuberculosis (TB) is frequently inferred in patients who present with lymphocyte predominant exudative effusions and high adenosine deaminase (ADA) levels. Two recent small retrospective studies suggested that the lactate dehydrogenase (LDH)/ADA ratio is significantly lower in TB than in non-TB pleural effusions and that the LDH/ADA ratio may be useful in differentiating pleural TB from other pleural exudates. We compared the pleural LDH/ADA ratios, ADA levels, and lymphocyte predominance of a prospectively collected cohort of patients with proven pleural TB (n = 160) to those with a definitive alternative diagnosis (n = 68). The mean pleural fluid LDH/ADA ratio was lower in patients with pleural TB than alternative diagnoses (6.2 vs. 34.3, p < 0.001). The area under the receiver operating characteristic curve was 0.92 (p < 0.001) for LDH/ADA ratio and 0.88 (p < 0.001) for an ADA ≥40 U/L alone. A ratio of ≤12.5 had the best overall diagnostic efficiency, while a ratio of ≤10 had a specificity of 90% and a positive predictive value of 95%, with a sensitivity of 78%, making it a clinically useful "rule in" value for pleural TB in high incidence settings. When comparing the LDH/ADA ratio to an ADA level ≥40 U/L in the presence of a lymphocyte predominant effusion, the latter performed better. When lymphocyte values are unavailable, our data suggest that the LDH/ADA ratio is valuable in distinguishing TB effusions from other pleural exudates.

Clinical utility of thoracoscopy in elderly tuberculous pleurisy patients under local anesthesia

INTRODUCTION

Diagnosing tuberculous pleurisy is important in Japan because it currently has a moderate tuberculosis prevalence. However, physicians often have difficulty making a diagnosis. It was reported that thoracoscopy under local anesthesia is useful for the diagnosis of tuberculous pleurisy, but there are no reports focusing on elderly patients.

METHODS

In this study, the usefulness of thoracoscopy under local anesthesia was evaluated in elderly patients. Among 170 patients who underwent thoracoscopy under local anesthesia at our hospital during 11 years from January 2008 to December 2018, those aged 75 years or older (n = 75) were investigated retrospectively.

RESULTS

A total of 55 patients underwent thoracoscopy under local anesthesia for detailed examination of pleural effusion of unknown cause. Of these, 18 were diagnosed as tuberculous pleurisy. The median age was 82 years (range: 75-92 years). The diagnosis of tuberculous pleurisy was made in 11 patients in whom Mycobacterium tuberculosis was detected and in four patients whose pathological findings indicated epithelioid granuloma accompanied by caseous necrosis. Clinical diagnosis was made in the remaining three patients based on thoracoscopic findings of the pleural cavity and a high level of adenosine deaminase in pleural fluid. No serious complications attributable to the examination were observed in any patient.

CONCLUSIONS

Thoracoscopy under local anesthesia was useful for the diagnosis of tuberculous pleurisy in elderly patients, with useful information being also obtained for the treatment of tuberculosis.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

IgG4-related disease with elevated adenosine deaminase in pleural effusion diagnosed clinically using thoracoscopy under local anesthesia and FDG-PET-CT

In general, we have to assume tuberculous pleurisy when a patient presents with pleural effusion and elevated adenosine deaminase (ADA). However, other diseases need to be considered, including immunoglobulin (Ig)G4-related disease (IgG4-RD). This case involved a 65-year-old asymptomatic man with right pleural effusion showing elevated ADA. He had no articular findings or rashes. Results were negative for all autoantibodies. Pleura, mediastinal lymph nodes, and areas around the aorta and vertebra showed high uptake of ¹⁸F-fluorodeoxyglucose (FDG) on positron-emission tomography-computed tomography (PET-CT). These findings were specific for IgG4-RD. Based on the results of FDG-PET-CT, we performed thoracoscopy under local anesthesia and bronchoscopy. Pleural biopsy and culture, and other examinations including sputum and blood yielded negative findings for tuberculous pleurisy. A pleural biopsy specimen showed IgG4-positive plasma cells and fibrosis without obliterative phlebitis or storiform fibrosis, and serum IgG4 was also high. The ratio of IgG4-to IgG-positive plasma cells was under 40%, and >10 IgG4-positive cells were seen in high-power fields. This case was classed as ‘possible IgG4-RD’ on the comprehensive diagnostic criteria for IgG4-RD, but did not meet the diagnostic criteria for IgG4-related respiratory disease. Prednisolone proved effective against the pleural effusion. We therefore clinically diagnosed IgG4-RD with pleural effusion based on the 2019 classification criteria for IgG4-RD in the United States. Although few cases of IgG4-RD with pleural effusion have been reported, this disease needs to be considered among the differential diagnoses for high-ADA pleural effusion. FDG-PET-CT and thoracoscopy under local anesthesia may be helpful for diagnosis.

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ImmunoglobulinG4-related disease (IgG4-RD) with pleural effusion is rare.

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We should assume IgG4-RD as one of the differential diagnoses of pleural effusion with high level of adenosine deaminase.

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Thoracoscopy under local anesthesia and 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET-CT) may be useful as an adjunctive tool for making a diagnosis of IgG4-RD.

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We could diagnosed as IgG4-RD with pleural effusion based on findings of FDG-PET-CT and thoracoscopy, and the responsiveness to prednisolone.

Prognostic factors for ARDS: clinical, physiological and atypical immunodeficiency

Background

Risk factors affecting the prognosis of acute respiratory distress syndrome (ARDS) in adults were investigated. The aim was to identify new predictors for ARDS patient prognosis, including those with clinical, pathophysiological, and atypical immunodeficiency.

Methods

ARDS patients were retrospectively included. The patients were grouped and analysed according to different oxygenation index grades and prognosis, and factors influencing prognosis and survival were examined. Adolescent patients, patients with typical immunodeficiency and patients who died within 24 h after being diagnosed with ARDS were excluded. The predictive value for mortality was determined by Cox proportional hazard analysis.

Results

In total, 201 patients who fulfilled the Berlin definition of ARDS were included. The severity of critical illness on the day of enrolment, as measured by the Acute Physiology and Chronic Health Evaluation (APACHE) II score (P = 0.016), Sequential Organ Failure Assessment (SOFA) score (P = 0.027), and PaO₂/FiO₂ (P = 0.000), worsened from mild to severe ARDS cases. Compared with survivors, non-survivors were significantly older and had higher APACHE II and SOFA scores. Moreover, significantly lower lymphocyte/neutrophil ratios and leukocyte counts were found among non-survivors than survivors (P = 0.008, P = 0.012). A moderate positive correlation between the lymphocyte/neutrophil and PaO₂/FiO₂ ratios (P = 0.023) was observed. In predicting 100-day survival in patients with ARDS, the area under the curve (AUC) for the lymphocyte/neutrophil ratio was significantly higher than those for the PaO₂/FiO₂ ratio alone, body mass index (BMI) alone, and the lymphocyte count alone (P = 0.0062, 0.0001, and 0.0154). Age (per log₁₀ years), BMI < 24, SOFA score, leukocyte count, and the lymphocyte/neutrophil ratio were independent predictors of 28-day mortality in ARDS patients. Additionally, ARDS patients with a lymphocyte/neutrophil ratio < 0.0537 had increased 28-day mortality rates (P = 0.0283). Old age affected both 28-day and 100-day mortality rates (P = 0.0064,0.0057).

Conclusions

Age (per log₁₀ years), BMI < 24, SOFA score, lymphocytes, and the lymphocyte/neutrophil ratio were independent predictors of 100-day mortality in patients with ARDS. The lymphocyte/neutrophil ratio may represent a potential molecular marker to evaluate atypical immunosuppression or impairment in patients with ARDS.

Laboratory Discrimination Between Neutrophilic Malignant and Parapneumonic Pleural Effusions

BACKGROUND

Malignant pleural effusion (MPE) occasionally demonstrates neutrophilic predominance, commonly found in parapneumonic pleural effusion (PPE). In comparison with lymphocytic MPE, neutrophilic MPE may have different characteristics associated with a more intense inflammatory response and poor prognosis. These characteristics of neutrophilic MPE may lead to inappropriate management and delayed diagnosis. Moreover, the limited diagnostic yield of microbiologic and cytologic tests makes early differential diagnosis between neutrophilic MPE and PPE more challenging. This study investigated objective laboratory findings to help distinguish neutrophilic MPE from PPE.

MATERIALS AND METHODS

A retrospective study was conducted on patients with neutrophilic MPE and PPE. Routine blood and pleural fluid data of the 2 groups were compared, and the diagnostic performances of predictors for neutrophilic MPE were assessed using receiver-operating characteristic curves.

RESULTS

Forty-one and 140 patients with neutrophilic MPE and PPE, respectively, were included. In final analysis, serum C-reactive protein, pleural fluid neutrophil-to-lymphocyte ratio, and pleural fluid carcinoembryonic antigen were significantly different between the 2 groups. With cut-off values of C-reactive protein <6.0 mg/dL, neutrophil-to-lymphocyte ratio <3.0 and carcinoembryonic antigen >8.0 ng/mL, the presence of any 2 or more parameters provided an area under the curve of 0.928 (95% CI, 0.851-0.999), yielding a sensitivity of 88%, specificity of 98%, positive predictive value of 92% and negative predictive value of 96% for identifying MPE.

CONCLUSIONS

MPE should be considered even in patients with neutrophilic exudative effusion, especially if at least 1 predictor for neutrophilic MPE is present. Our results may help guide differentiation of neutrophilic MPE from PPE.

Improved early diagnosis of difficult cases of tuberculous pleural effusion by combination of thoracoscopy with immunological tests

INTRODUCTION

Although pleural effusion is a common clinical manifestation, the differential diagnosis of the cause of pleural effusion is often challenging, especially in the early differentiation of tuberculous pleurisy (TP) from other pleural effusion. The aim of this study was to evaluate the performance of commonly used laboratory tests for the early diagnosis of difficult cases of pleural effusion.

METHODS

Patients with undiagnosed pleural effusion were enrolled and subjected to five laboratory tests including thoracoscopy, pleural fluid adenosine deaminase assay (ADA), serum tuberculosis antibody test (TB-antibody), tuberculin skin test (TST), and T-SPOT.TB assay. The diagnosis of TP was established based on pleural histology and mycobacterial culture. The different tests were compared for diagnostic performance.

RESULTS

A total of 106 patients were enrolled; their mean age was 53 years and 70.8% were male. Seventy-two (68%) of them were confirmed to have TP. When used individually, the five laboratory tests showed highly variable performance parameters, including sensitivity ranging from 46% to 92% and specificity ranging from 33% to 82%. When used in different combinations, thoracoscopy combined with TST or TB-antibody showed the optimal performance parameters, with a sensitivity of 80.8% and a specificity of 85.7%.

CONCLUSIONS

The results of this study suggest that the combination of thoracoscopy with TST or TB-antibody test is the best choice for the early diagnosis of difficult cases of TP in high TB burden countries.

Calpain and spectrin breakdown products as potential biomarkers in tuberculous pleural effusion

Background

Early diagnosis of tuberculous pleural effusion (TPE) remains difficult. Calpain is a family of calcium-dependent endopeptidase that plays an important role in extracellular matrix (ECM) remodeling and collagen synthesis. The aim of this study was to explore the diagnostic value of pleural fluid angiotensin-converting enzyme (ACE), calpain-1, spectrin breakdown products (SBDP), and matrix metalloproteinase-1 (MMP-1) in TPE and malignant pleural effusion (MPE).

Methods

The study included 47 patients with TPE, 28 patients with MPE, and 10 patients with transudate of non-tuberculous and non-malignant origin as controls. Calpain-1, ACE, SBDP, and MMP-1 levels in pleural fluid were measured by the ELISA method.

Results

ACE, calpain-1, SBDP, and MMP-1 levels were higher in TPE than MPE and transudate (all, P<0.05). On multivariate logistic regression analysis, adenosine deaminase (ADA) ≥40 IU/mL, calpain-1 ≥787 ng/mL, and SBDP ≥2.745 ng/mL were independent factors associated with TPE. The predicted probability of TPE based on these three predictors had an area under the receiver operating characteristic (ROC) curve of 0.985, with 97.9% sensitivity and 86.6% specificity under a cut-off value of 0.326. In patients with TPE, residual pulmonary thickening (RPT) was associated with significantly higher calpain-1, SBDP, and MMP-1 levels (all, P<0.05) versus cases without RPT.

Conclusions

Our results suggest that the overproduction of calpain-1 and SBDP is associated with pleural fibrosis in tuberculous pleurisy. While ADA is a conventional marker for diagnostic TPE, the simultaneous measurement of calpain-1 and SBDP l in pleural fluid may improve the diagnostic efficacy.

Development of a clinical prediction rule for the diagnosis of pleural tuberculosis in Peru

OBJECTIVES

To develop a clinical prediction rule (CPR) for the diagnosis of pleural tuberculosis (PT) in patients with pleural exudates in Peru.

METHODS

Clinical and laboratory information was collected from patients with exudative pleural effusion attending two reference hospitals in Lima, Peru. Predictive findings associated with PT in a multiple logistic regression model were used to develop the CPR. A definite diagnosis of PT was based on a composite reference standard including bacteriological and/or histological analysis of pleural fluid and pleural biopsy specimens.

RESULTS

A total of 238 patients were included in the analysis, of whom 176 had PT. Age, sex, previous contact with a TB patient, presence of lymphadenopathy, and pleural adenosine deaminase (ADA) levels were found to be independently associated with PT. These predictive findings were used to construct a CPR, for which the area under the receiver operating characteristics curve (AUC) was 0.92. The single best cut-off point was a score of ≥60 points, which had a sensitivity of 88%, specificity of 92%, a positive likelihood ratio of 10.9, and a negative likelihood ratio of 0.13.

CONCLUSIONS

The CPR is accurate for the diagnosis of PT and could be useful for treatment initiation while avoiding pleural biopsy. A prospective evaluation is needed before its implementation in different settings.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Pleural fluid tests to diagnose tuberculous pleuritis

PURPOSE OF REVIEW

This article summarizes current data regarding the accuracy of pleural fluid tests assisting the diagnosis of tuberculous pleuritis (TBP).

RECENT FINDINGS

No pleural fluid test reliably rules-in TBP in settings with low TBP prevalence. Interferon-γ) alone or in combination with adenosine deaminase (ADA) is more reliable than ADA for this purpose in nonlow prevalences. ADA can reliably rule-out TBP in prevalences of less than 40% although in higher prevalences the product of interleukin-27 and ADA is the most accurate rule-out test.

SUMMARY

The definite diagnosis of TBP requires the isolation of Mycobacterium tuberculosis from pleural fluid or biopsies. Because of the low sensitivity of pleural fluid cultures and the invasiveness of pleural biopsy techniques, the concept of a pleural fluid test that accurately establishes or excludes TBP diagnosis has been proposed. Numerous pleural fluid tests have been evaluated for this purpose with ADA being the most widely accepted one. During the last years, it has been demonstrated that the ability of ADA to rule-in or rule-out TBP is affected by the prevalence of TBP in the setting where the test is used. The complementary use of interferon-γ or interleukin-27 increases the ability of ADA to rule-in or rule-out the disease, respectively.

Pleural effusion biomarkers and computed tomography findings in diagnosing malignant pleural mesothelioma: A retrospective study in a single center

In this study, we aimed to examine the clinical value of the pleural effusion (PE) biomarkers, soluble mesothelin-related peptide (SMRP), cytokeratin 19 fragment (CYFRA 21–1) and carcinoembryonic antigen (CEA), and the utility of combining chest computed tomography (CT) findings with these biomarkers, in diagnosing malignant pleural mesothelioma (MPM). We conducted a retrospective cohort study in a single center. Consecutive patients with undiagnosed pleural effusions who underwent PE analysis between September 2014 and August 2016 were reviewed. This study included 240 patients (32 with MPM and 208 non-MPM). SMRP and the CYFRA 21-1/CEA ratio had a sensitivity and specificity for diagnosing MPM of 56.3% and 86.5%, and 87.5% and 74.0%, respectively. Using receiver operating characteristics (ROC) curve analysis of the ability of these markers to distinguish MPM from all other PE causes, the area under the ROC curve (AUC) for SMRP and the CYFRA 21-1/CEA ratio was 0.804 and 0.874, respectively. The sensitivity and specificity of SMRP combined with the CYFRA 21-1/CEA ratio were 93.8% and 64.9%, respectively. The sensitivity of the combination of SMRP, the CYFRA 21-1/CEA ratio, and the presence of Leung’s criteria (a chest CT finding that is suggestive of malignant pleural disease) was 93.8%. In conclusion, the combined PE biomarkers had a high sensitivity for diagnosing MPM, although the addition of chest CT findings did not improve the sensitivity of SMRP combined with the CYFRA 21-1/CEA ratio. Combination of these biomarkers helped to rule out MPM effectively among patients at high risk of suffering MPM and would be valuable especially for old frail patients who have difficulty in undergoing invasive procedures such as thoracoscopy.

CT findings of pulmonary tuberculosis and tuberculous pleurisy in diabetes mellitus patients

PURPOSE

We aimed to assess computed tomography (CT) findings of pulmonary tuberculosis (TB) and TB pleurisy in diabetes mellitus (DM) patients and to evaluate the effect of duration of DM on radiologic findings of pulmonary TB and TB pleurisy.

METHODS

Ninety-three consecutive patients diagnosed as active pulmonary TB with underlying DM were enrolled in our study. As a control group, 100 pulmonary TB patients without DM were randomly selected. TB patients with DM were subdivided into two subgroups depending on diabetes duration of ≥10 years or <10 years. Medical records and CT scans of the patients were retrospectively reviewed and compared.

RESULTS

Bilateral pulmonary involvement (odds ratio [OR]=2.39, P = 0.003), involvement of all lobes (OR=2.79, P = 0.013), and lymph node enlargement (OR=1.98, P = 0.022) were significantly more frequent CT findings among TB patients with DM compared with the controls. There were no statistically significant differences in CT findings of pulmonary TB depending on the duration of DM.

CONCLUSION

Bilateral pulmonary involvement, involvement of all lobes, and lymph node enlargement are significantly more common CT findings in TB patients with underlying DM than in patients without DM. Familiarity with the CT findings may be helpful to suggest prompt diagnosis of pulmonary TB in DM patients.

Diagnostic Potential of Circulating Biomarkers in Adenosine Deaminase Diagnosed Pleural Tuberculosis Cases

Pleural tuberculosis accounts for nearly 20% of Extra pulmonary tuberculosis. Adenosine deaminase, commonly used biomarker for the diagnosis, is non specific and there is paucity of literature on its correlation with conventional or newer methods for the diagnosis of extra pulmonary forms of TB. The aim of the study was to assess diagnostic potential of T cell function markers [interferon (IFN-γ), interleukin (IL-2) and IFN-γ/IL-2 ratio]; macrophage activation marker [neopterin]; and oxidative stress markers [protein carbonyl and malondialdehyde (MDA)] in pleural tuberculosis. 26 pleural TB cases diagnosed on the basis of suggestive chest X-ray and raised serum ADA levels and healthy controls were included in the study. Pleural fluid specimens were subjected to Zeihl Neelsen staining and culture on Lowenstein Jensen medium. Serum IFN-γ, IL-2, neopterin and protein carbonyl levels detection were done by ELISA and MDA levels were determined by measuring the thiobarbituric acid reactive substances. Median serum levels of IFN-γ, IL-2, IFN-γ/IL-2 ratio, neopterin, protein carbonyl and MDA were significantly different between cases and controls. Levels of all biomarkers except IL-2 were significantly higher in cases with contact history. Mean levels of ADA and ESR were 46.27 U/L and 46.62 mm/hr in PTB cases. AUC for IFN-γ, IL-2, IFN-γ/IL-2 ratio, neopterin, protein carbonyl and MDA were significantly discriminative for cases and controls. IFN-γ/IL-2 ratio was best discriminatory biomarker with highest area under ROC curve. Though no correlation was seen between ADA and any of the six biomarkers, ESR levels correlated significantly with all biomarkers except IL-2 by spearman's correlation coefficient. Though all the circulating biomarkers under study provide useful supportive evidence for the diagnosis of PTB, further studies involving diverse control groups particularly non-PTB effusion are needed to validate these results.

Performance of clinical prediction rules for diagnosis of pleural tuberculosis in a high-incidence setting

OBJECTIVES

Diagnosis of pleural tuberculosis (PT) is still a challenge, particularly in resource-constrained settings. Alternative diagnostic tools are needed. We aimed at evaluating the utility of Clinical Prediction Rules (CPRs) for diagnosis of pleural tuberculosis in Peru.

METHODS

We identified CPRs for diagnosis of PT through a structured literature search. CPRs using high-complexity tests, as defined by the FDA, were excluded. We applied the identified CPRs to patients with pleural exudates attending two third-level hospitals in Lima, Peru, a setting with high incidence of tuberculosis. Besides pleural fluid analysis, patients underwent closed pleural biopsy for reaching a final diagnosis through combining microbiological and histopathological criteria. We evaluated the performance of the CPRs against this composite reference standard using classic indicators of diagnostic test validity.

RESULTS

We found 15 eligible CPRs, of which 12 could be validated. Most included ADA, age, lymphocyte proportion and protein in pleural fluid as predictive findings. A total of 259 patients were included for their validation, of which 176 (67%) had PT and 50 (19%) malignant pleural effusion. The overall accuracy of the CPRs varied from 41% to 86%. Two had a positive likelihood ratio (LR) above 10, but none a negative LR below 0.1. ADA alone at a cut-off of ≥40 IU attained 87% diagnostic accuracy and had a positive LR of 6.6 and a negative LR of 0.2.

CONCLUSION

Many CPRs for PT are available. In addition to ADA alone, none of them contributes significantly to diagnosis of PT.

Validity of tuberculous pleuritis diagnosed in a resource-constrained setting in Dindigul district of Tamil Nadu

Context:

Majority of the Indians live in rural areas where resource constrained settings depend on cheaper and less invasive tests to diagnose extrapulmonary tuberculosis (TB). The decline in prevalence of TB in the country could affect the validity of the diagnosis. The aim was to measure validity of the pleural fluid study of proteins, lactate dehydrogenase (LDH), and cell counts in diagnosis of tuberculous pleuritis.

Materials and Methods:

This was a cross-sectional study conducted in a 300 bedded secondary care hospital in rural Tamil Nadu. Exhaustive sampling was performed during April 2013 to March 2014. Pleural fluid study of 54 patients with exudative pleural effusion was conducted. Diagnosis was established by closed needle pleural biopsy. Receiver operator curves were plotted and area under curve (AUC) was calculated for various parameters. Sensitivity, specificity, and predictive values were calculated for different cut-off values of the parameter with significant AUC.

Results:

Prevalence of tuberculous pleural effusion was 56% (95% confidence interval [95% CI] - 42.5–69.5%). Lymphocyte predominance in pleural fluid was the only valid test, and cut-off >80% had sensitivity of 70.0% (95% CI - 53.3–86.7%) and specificity of 70.8% (95% CI - 52.2–89.4%). Pleural fluid pH, protein or its ratio with serum protein, sugar, total leukocyte count, LDH or its ratio with serum LDH; erythrocyte sedimentation rate were not valid screening tests.

Conclusions:

Lymphocyte predominance > 80% can be used as a marker of tuberculous pleuritis. Since the prevalence of tuberculous pleuritis in India has come down considerably, newer tests need to be included to make a valid diagnosis.

Differentiating Malignant from Tubercular Pleural Effusion by Cancer Ratio Plus (Cancer Ratio: Pleural Lymphocyte Count)

Background. We performed prospective validation of the cancer ratio (serum LDH : pleural ADA ratio), previously reported as predictive of malignant effusion retrospectively, and assessed the effect of combining it with “pleural lymphocyte count” in diagnosing malignant pleural effusion (MPE). Methods. Prospective cohort study of patients hospitalized with lymphocyte predominant exudative pleural effusion in 2015. Results. 118 patients, 84 (71.2%) having MPE and 34 (28.8%) having tuberculous pleural effusion (TPE), were analysed. In multivariate logistic regression analysis, cancer ratio, serum LDH : pleural fluid lymphocyte count ratio, and “cancer ratio plus” (ratio of cancer ratio and pleural fluid lymphocyte count) correlated positively with MPE. The sensitivity and specificity of cancer ratio, ratio of serum LDH : pleural fluid lymphocyte count, and “cancer ratio plus” were 0.95 (95% CI 0.87–0.98) and 0.85 (95% CI 0.68–0.94), 0.63 (95% CI 0.51–0.73) and 0.85 (95% CI 0.68–0.94), and 97.6 (95% CI 0.90–0.99) and 94.1 (95% CI 0.78–0.98) at the cut-off level of >20, >800, and >30, respectively. Conclusion. Without incurring any additional cost, or requiring additional test, effort, or time, cancer ratio maintained and “cancer ratio plus” improved the specificity of cancer ratio in identifying MPE in the prospective cohort.

Role of the Neutrophil-Lymphocyte Ratio in the Differential Diagnosis of Exudative Pleural Effusion

OBJECTIVES:

Pleural effusion is a common diagnostic and clinical problem. The differential diagnosis of pleural effusion may be difficult and may require several procedures, including invasive ones. Certain studies have investigated biochemical parameters to facilitate the diagnosis of exudative pleural effusion; however, it remains a challenging problem in clinical practice. We aimed to investigate the potential role of the neutrophil-lymphocyte ratio, which can be easily obtained by determining the cell count of the pleural fluid, in the differential diagnosis of exudative pleural effusion.

METHODS:

Records from patients who underwent thoracentesis and pleural fluid analysis between May 1, 2013, and March 1, 2015, were obtained from the electronic database of our hospital. The patients who met the inclusion criteria were divided into five groups according to their diagnosis: malignant pleural effusion, para-malignant pleural effusion, para-pneumonic effusion, tuberculosis-related effusion or other. The neutrophil-lymphocyte ratio value was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. The patient groups were compared according to the given parameter.

RESULTS:

A total of 465 patients who met the inclusion criteria among 1616 patients with exudative pleural effusion were included in the study. The mean neutrophil-lymphocyte ratio value was significantly lower in tuberculosis-related pleural effusion compared to malignant, para-pneumonic and para-malignant effusions (p=0.001, p=0.001, p=0.012, respectively). The areas under the curve for tuberculosis pleurisy compared to malignant, para-pneumonic and para-malignant effusions were 0.38, 0.36, and 0.37, respectively. Lower cut-off values had higher sensitivity but lower specificity for tuberculosis pleurisy, while higher cut-off values had higher specificity but lower sensitivity for this condition.

CONCLUSION:

The pleural fluid neutrophil-lymphocyte ratio, which is an inexpensive, reproducible, and easily calculated hematological parameter, may facilitate the differential diagnosis of pleural effusion.

Increased level of soluble adenosine deaminase in bone marrow of visceral leishmaniasis patients: an inverse relation with parasite load

Adenosine deaminase (ADA) which degrades adenosine to inosine, is known to be pro-inflammatory molecule in many diseases. Adenosine suppresses the functioning of the immune system and thus promotes dissemination of the parasite. In our previous finding, the level of soluble ADA in serum of visceral leishmaniasis (VL) was found to be increased as compared to healthy controls. However, it cannot be fairly interpreted unless their level is demonstrated at the disease site, where the parasite resides. We designed this study to correlate the level of soluble ADA (sADA) with parasitic load at the disease site i.e. bone marrow (BM). We found increased levels of sADA in BM as compared to the unaffected BM. Furthermore, a significant inverse correlation is observed between the parasite load and level of sADA at the disease site.

Development and Validation of the COMPLES Score for Differentiating Between Tuberculous Effusions with Low Pleural pH or Glucose and Complicated Parapneumonic Effusions

BACKGROUND

The frequency of "complicated" pleural effusions (CPE) (i.e., pleural fluid pH ≤ 7.2 and/or glucose ≤60 mg/dL) of tuberculous origin (CTPE) is not well reported. This study aims to quantify their prevalence, and develop a score to differentiate CTPE from complicated parapneumonic effusions (CPPE).

METHODS

Retrospective analysis of databases from three Spanish hospitals which included patients with CTPE and CPPE. Forty percent of the study population served to generate a scoring system (COMPLES, COMplicated PLeural Effusion Score) that was further validated in the remaining 60 %.

RESULTS

During the study period (1992-2015) 549 patients were diagnosed with tuberculous effusions and 434 parapneumonic effusions, of whom 25 and 64 %, respectively, had CPE. COMPLES was based on the combination of pleural fluid adenosine deaminase (ADA), the percentage of mononuclear cells (MNC %), pH, and age. The cutoff values and assigned scores were: ADA (<46 IU/L [0 points], 46-100 IU/L [4 points], ≥100 IU/L [6 points]), MNC % (<10 % [0 points], 10-50 [3 points], >50 [8 points]), pH (<7.07 [0 points], 7.07-7.20 [3 points], >7.20 [5 points]), and age (≥30 [0 points], <30 years [3 points]). A sum of 12 or more points had 97 % sensitivity, 92 % specificity, likelihood ratio positive 12.3, likelihood ratio negative 0.03, and area under the curve of 0.947 for identifying CTPE versus CPPE in the validation set.

CONCLUSIONS

CPE is not an unusual presentation of tuberculosis. A simple new scoring system provides a reliable tool for differentiating between CTPE and CPPE.

A man with pleural effusion and ascites

A male lifelong nonsmoker aged 58 years with no prior asbestos exposure complained of gradual worsening breathlessness over 3 months. This was associated with abdominal and leg swelling and a 2-kg weight loss. He had no fever, night sweats, hemoptysis, joint pain, rash, abdominal pain, chest pain, or orthopnea. The patient had no recent travel or contact with pulmonary TB. He had stage I left-side testicular seminoma treated with left-sided radical orchidectomy 10 years previous and recently received a diagnosis of Child's B alcoholic liver cirrhosis. His hepatitis B and C screen result was normal.

Tuberculous pleural effusions: advances and controversies

On a global scale, tuberculosis (TB) remains one of the most frequent causes of pleural effusions. Our understanding of the pathogenesis of the disease has evolved and what was once thought to be an effusion as a result of a pure delayed hypersensitivity reaction is now believed to be the consequence of direct infection of the pleural space with a cascade of events including an immunological response. Pulmonary involvement is more common than previously believed and induced sputum, which is grossly underutilised, can be diagnostic in approximately 50%. The gold standard for the diagnosis of tuberculous pleuritis remains the detection of Mycobacterium tuberculosis in pleural fluid, or pleural biopsy specimens, either by microscopy and/or culture, or the histological demonstration of caseating granulomas in the pleura along with acid fast bacilli (AFB). In high burden settings, however, the diagnosis is frequently inferred in patients who present with a lymphocytic predominant exudate and a high adenosine deaminase (ADA) level, which is a valuable adjunct in the diagnostic evaluation. ADA is generally readily accessible, and together with lymphocyte predominance justifies treatment initiation in patients with a high pre-test probability. Still, false-negative and false-positive results remain an issue. When adding closed pleural biopsy to ADA and lymphocyte count, diagnostic accuracy approaches that of thoracoscopy. The role of other biomarkers is less well described. Early pleural drainage may have a role in selected cases, but more research is required to validate its use and to define the subpopulation that may benefit from such interventions.

Development and Evaluation of the New Predictive Models in Tuberculous Pleuritis

Different pleural fluid biomarkers have been found useful in the discrimination between tuberculous pleural effusion (TPE) and non-TPE, with interferon gamma (IFN-γ) showing the highest single marker diagnostic accuracy. The aim of the present study was to develop predictive models based on clinical data and pleural fluid biomarkers, other than IFN-γ, which could be applied in differentiating TPE and non-TPE. Two hundred and forty two patients with newly diagnosed pleural effusion were prospectively enrolled. Upon completion of the diagnostic procedures, the underlying disease was identified in 203 patients (117 men and 86 women, median age 65 years; 44 patients with TPE and 159 with non-TPE) who formed the proper study group. Pleural fluid level of ADA, IFN-γ, IL-2, IL-2sRα, IL-12p40, IL-18, IL-23, IP-10, Fas-ligand, MDC, and TNF-α was measured and then ROC analysis and multivariate logistic regression were used to construct the predictive models. Two predictive models with very high diagnostic accuracy (AUC > 0.95) were developed. The first model included body temperature, white blood cell count, pleural fluid ADA and IP-10. The second model was based on age, sex, body temperature, white blood cell count, pleural fluid lymphocyte percentage, and IP-10 level. We conclude that two new predictive models based on clinical and laboratory data demonstrate very high diagnostic performance and can be potentially used in clinical practice to differentiate between TPE and non-TPE.

[Contribution of pleural fluid analysis to the diagnosis of pleural effusion]

Analysis of pleural fluid can have, on its own, a high diagnostic value. In addition to thoracocentesis, a diagnostic hypothesis based on medical history, physical examination, blood analysis and imaging tests, the diagnostic effectiveness will significantly increase in order to establish a definite or high probable diagnosis in a substantial number of patients. Differentiating transudates from exudates by the classical Light's criteria helps knowing the pathogenic mechanism resulting in pleural effusion, and it is also useful for differential diagnosis purposes. An increased N-terminal pro-brain natriuretic peptide, both in the fluid and in blood, in a due clinical context, is highly suggestive of heart failure. The presence of an increased inflammatory marker, such as C-reactive protein, together with the presence of over 50% of neutrophils is highly suggestive of parapneumonic pleural effusion. If, in these cases, the pH is<7.20, then the likelihood of complicated pleural effusion is high. There remains to be demonstrated the usefulness of other markers to differentiate complicated from uncomplicated effusions. An adenosine deaminase > 45 U/L and>50% lymphocytes is suggestive of tuberculosis. If a malignant effusion is suspected but the cytological result is negative, increased concentrations of some markers in the pleural fluid can yield high specificity values. Increased levels of mesothelin and fibruline-3 are suggestive of mesothelioma. Immunohistochemical studies can be useful to differentiate reactive mesothelial cells, mesothelioma and metastatic adenocarcinoma. An inadequate use of the information provided by the analysis of pleural fluid would results in a high rate of undiagnosed effusions, which is unacceptable in current clinical practice.

Diagnostic accuracy of tumor necrosis factor-alpha, interferon-gamma, interleukin-10 and adenosine deaminase 2 in differential diagnosis between tuberculous pleural effusion and malignant pleural effusion

Background

The current study was performed to investigate the potential biomarkers for the differential diagnosis of tuberculous pleural effusion (TPE) and malignant pleural effusions (MPE).

Methods

Among ninety patients (n = 90) involved in the study, 47 with tuberculous pleural effusion aged from 18 to 70 and 43 with secondary malignant pleural effusion aged from 34 to 78. We tested the pleural levels of TNF-α, IFN-γ and IL-10 as well as the enzyme activity of ADA₂, and then we compared the differential diagnostic efficiencies of those biochemical parameters with ADA between the two groups.

Results

Our results show that, the concentrations of pleural TNF-α (45.55 ± 15.85 ng/L), IFN-γ (114.97 ± 27.85 ng/L) as well as activities of ADA₂ (35.71 ± 10.00 U/L) and ADA (39.39 ± 10.60 U/L) in tuberculous group were significantly higher compared to malignant group. Furthermore, according to the ROC curve analysis the thresholds of TNF-α, IFN-γ, ADA₂ and ADA were found to be 30.3 ng/L, 103.65 ng/L, 29.45 U/L, and 39.00 U/L, respectively. TNF-α, IFN-γ and ADA₂ yielded better sensitivity, specificity, and accuracy of the diagnosis than ADA. Our investigation further revealed that the combinations of TNF-α and ADA₂ further increased the specificity and accuracy for the differential diagnosis.

Conclusion

In conclusion, we found that TNF-α, IFN-γ, ADA and ADA₂ all increased in TPE. Combinations of the TNF-α and ADA₂ yielded the best specificity and accuracy for the differential diagnosis of TPE from MPE. Our investigation suggests that the applications of TNF-α together with ADA₂ may contribute to more efficient diagnosis strategies in the management of discrimination between tuberculous and malignant pleural effusions.

Tuberculous pleurisy: an update

Tuberculous pleurisy is the most common form of extrapulmonary tuberculosis in Korea. Tuberculous pleurisy presents a diagnostic and therapeutic problem due to the limitations of traditional diagnostic tools. There have been many clinical research works during the past decade. Recent studies have provided new insight into the tuberculous pleurisy, which have a large impact on clinical practice. This review is a general overview of tuberculous pleurisy with a focus on recent findings on the diagnosis and management.

Tuberculous pleural effusion

Tuberculous pleural effusion (TBPE) is the most common form of extrapulmonary tuberculosis (TB) in Spain, and is one of the most frequent causes of pleural effusion. Although the incidence has steadily declined (4.8 cases/100,000population in 2009), the percentage of TBPE remains steady with respect to the total number of TB cases (14.3%-19.3%). Almost two thirds are men, more than 60% are aged between 15-44years, and it is more common in patients with human immunodeficiency virus. The pathogenesis is usually a delayed hypersensitivity reaction. Symptoms vary depending on the population (more acute in young people and more prolonged in the elderly). The effusion is almost invariably a unilateral exudate (according to Light's criteria), more often on the right side, and the tuberculin test is negative in one third of cases. There are limitations in making a definitive diagnosis, so various pleural fluid biomarkers have been used for this. The combination of adenosine deaminase and lymphocyte percentage may be useful in this respect. Treatment is the same as for any TB. The addition of corticosteroids is not advisable, and chest drainage could help to improve symptoms more rapidly in large effusions.

The diagnostic efficacy of adenosine deaminase in tubercular effusion

OBJECTIVE

This study aims to evaluate the diagnostic efficacy of adenosine deaminase in tubercular effusions.

METHODS

This study was conducted at the Department of General Medicine and Cardiovascular and Thoracic Surgery, SKIMS, for a period of two years between November 2008 and November 2010. A total of 57 patients presenting with pleural effusions during the two-year study period, who presented with clinical manifestations suggestive of tuberculosis (i.e., the presence of productive cough, low-grade fever, night sweats, weight loss, and chest pain, especially if these symptoms last (3)4 weeks) were included in the study. If the patients presented with less than two of these symptoms, and especially if the clinical manifestations were of <4 weeks duration, they were excluded from the study.

RESULTS

The mean adenosine deaminase activity level in all the 57 patients was 109 U/L while the mean adenosine deaminase activity levels in pleural TB patients was 80 U/, and 64 U/L in the controls (p=0.381). Considering 40 U/L as the cut off, the results were positive in 35 out of 39 tuberculosis patients and 9 out of 18 controls. The sensitivity of adenosine deaminase for tubercular effusions worked out to be 90%, with only 50% specificity.

CONCLUSION

This study suggests that the estimation of adenosine deaminase activity in pleural fluid is a rapid diagnostic tool for differentiation of tubercular and non tubercular-effusions. The sensitivity and specificity of adenosine deaminase for tubercular effusions in this study was 90% and 50% respectively.

Role of the neutrophil-lymphocyte count ratio in the differential diagnosis between pulmonary tuberculosis and bacterial community-acquired pneumonia

Background

Differential diagnosis between pulmonary tuberculosis (TB) and bacterial community-acquired pneumonia (CAP) is often challenging. The neutrophil-lymphocyte count ratio (NLR), a convenient marker of inflammation, has been demonstrated to be a useful biomarker for predicting bacteremia. We investigated the usefulness of the NLR for discriminating pulmonary TB from bacterial CAP in an intermediate TB-burden country.

Methods

We retrospectively analyzed the clinical and laboratory characteristics of 206 patients suspected of having pulmonary TB or bacterial CAP from January 2009 to February 2011. The diagnostic ability of the NLR for differential diagnosis was evaluated and compared with that of C-reactive protein.

Results

Serum NLR levels were significantly lower in patients with pulmonary TB than in patients with bacterial CAP (3.67±2.12 vs. 14.64±9.72, P<0.001). A NLR <7 was an optimal cut-off value to discriminate patients with pulmonary TB from patients with bacterial CAP (sensitivity 91.1%, specificity 81.9%, positive predictive value 85.7%, negative predictive value 88.5%). The area under the curve for the NLR (0.95, 95% confidence interval [CI], 0.91-0.98) was significantly greater than that of C-reactive protein (0.83, 95% CI, 0.76-0.88; P=0.0015).

Conclusions

The NLR obtained at the initial diagnostic stage is a useful laboratory marker to discriminate patients with pulmonary TB from patients with bacterial CAP in an intermediate TB-burden country.

Clinical Utility of Two Interferon-gamma Release Assays on Pleural Fluid for the Diagnosis of Tuberculous Pleurisy

Background

The release of interferon-gamma (IFN-γ) by T lymphocytes increases after rechallenge with Mycobacterium tuberculosis antigen, especially, at a localized site of tuberculosis (TB) infection. We aimed to compare the clincial efficacy of two commercial IFN-γ release assays from pleural fluid for the diagnosis in tuberculous pleurisy.

Methods

We performed T-SPOT.TB and QuantiFERON-TB Gold tests simultaneously on pleural fluid and peripheral blood samples from patients with pleural effusion, in South Korea, an area with intermediate TB burden.

Results

Thirty-six patients were enrolled prospectively, and tuberculous pleurisy was found in 21 patients. Both the numbers of IFN-γ secreting T cells and the concentration of IFN-γ were greater in the pleural tuberculous group, comparing with the non-tuberculous group. Moreover, in the tuberculous group, there was a significant difference in IFN-γ producing spot-forming cells using the T-SPOT.TB method between pleural fluid and peripheral blood. The receiver operating characteristic (ROC) curve, was the greatest for pleural fluid T-SPOT.TB test, followed by peripheral blood T-SPOT.TB test, peripheral blood QuantiFERON-TB Gold test, and pleural fluid QuantiFERON-TB Gold test (area under the ROC curve of 0.956, 0.890, 0.743, and 0.721, respectively). The T-SPOT.TB assay produced less indeterminate results than did QuantiFERON-TB Gold assay in both pleural fluid and peripheral blood.

Conclusion

These findings suggest that the pleural fluid T-SPOT.TB test could be the most useful test among the IFN-γ release assays for diagnosing tuberculous pleurisy in an area with an intermediate prevalence of TB infection.

Amplified Mycobacterium tuberculosis direct test for diagnosing tuberculous pleurisy--a diagnostic accuracy study

BACKGROUND

The study was designed to investigate the clinical usefulness of Amplified Mycobacterium Tuberculosis Direct (AMTD) tests for diagnosing TB pleurisy.

METHODS

One hundred and fifty-two patients for whom the exclusion of tuberculous pleural effusion was necessary were retrospectively analyzed.

RESULTS

The sensitivity of AMTD in diagnosing pleural TB was 36.4% (20 of 55). Combining sputum and pleural effusion AFB smear, pleural biopsy, and AMTD test of pleural effusion increased sensitivity to 82.5% (33/40). There were significantly higher percentages of neutrophils in the pleural effusion in the positive than in the negative AMTD group (38.0 ± 6.7% vs. 11.1 ± 3.7%, p<0.001). Patients with symptom duration <18 days prior to pleural effusion studies had more positive AMTD tests than those with symptom >18 days (70% vs. 31.4%; OR 5.09; 95% CI 1.54-16.79; p = 0.011).

CONCLUSIONS

Combining AMTD tests with conventional diagnostic methods offer good sensitivity for pleural TB diagnosis. Patients in the early course of the disease are better candidates for AMTD tests.

Diagnostic accuracy of adenosine deaminase and lymphocyte proportion in pleural fluid for tuberculous pleurisy in different prevalence scenarios

Background

Tuberculous pleural effusion (TPE) is a paucibacillary manifestation of tuberculosis, so isolation of Mycobacterium tuberculosis is difficult, biomarkers being an alternative for diagnosis. Adenosine deaminase (ADA) is the most cost-effective pleural fluid marker and is routinely used in high prevalence settings, whereas its value is questioned in areas with low prevalence. The lymphocyte proportion (LP) is known to increase the specificity of ADA for this diagnosis. We analyse the diagnostic usefulness of ADA alone and the combination of ADA ≥40 U/l (ADA₄₀) and LP≥50% (LP₅₀) in three different prevalence scenarios over 11 years in our area.

Materials and Methods

Biochemistry, cytology and microbiology studies from 472 consecutive pleural fluid samples were retrospectively analyzed. ADA and differential cell count were determined in all samples. We established three different prevalence periods, based on percentage of pleural effusion cases diagnosed as tuberculosis: 1998–2000 (31.3%), 2001–2004 (11.8%), and 2005–2008 (7.4%). ROC curves, dispersion diagrams and pre/post-test probability graphs were produced. TPE accounted for 73 episodes (mean prevalence: 15.5%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for ADA₄₀ were 89%, 92.7%, 69.2% and 97.9%, respectively. For ADA₄₀+LP₅₀ the specificity and PPV increased (98.3% and 90%) with hardly any decrease in the sensitivity or NPV (86.3% and 97.5%). No relevant differences were observed between the three study periods.

Conclusions/Significance

ADA remains useful for the diagnosis of TPE even in low-to-intermediate prevalence scenarios when combined with the lymphocyte proportion.

Markers for differentiation of tubercular pleural effusion from non-tubercular effusion

BACKGROUND

The limitations of the conventional methods for diagnosing tuberculosis (TB) have spurred multi-faceted research activities throughout the world. This study aims to explore the levels of adenosine deaminase (ADA) and interleukins in pleural effusion of tuberculous, malignant, and miscellaneous origin for differential diagnosis of tubercular and non-tubercular effusion.

METHOD

Adenosine deaminase was estimated by kinetic method employing xanthine oxidase while interleukins were measured using commercially available ELISA kits in pleural fluids of tubercular and non-tubercular origin.

RESULTS

Pleural fluids INF-γ, sIL-2R, TNF-α and ADA were significantly higher in TB group (n = 48) as compared to the non-TB group (n = 33) (mean ± SD: INF-γ; 1,958.7 ± 896.5 pg/mL vs 356.9 ± 733.6 pg/mL, sIL-2R; 6,101 ± 1,753.8 pg/mL vs 3,166 ± 2,611.1 ± pg/mL, TNF-α; 195.5 ± 292.1 pg/mL vs 59.7 ± 128.9 pg/mL, ADA; 123.6 ± 81.8 IU/L vs 48 ± 48.5 IU/L, P < 0.01).

CONCLUSION

INF-(is more sensitive and specific than ADA for the diagnosis of TB and should be added to the armamentarium of the diagnostic workup of pleural fluids for timely and accurate diagnosis of TB and differentiation of tubercular pleural effusion from non-tubercular effusion.