Pleural fluid parameters identifying complicated parapneumonic effusions.

BACKGROUND: Controversy exists regarding the clinical utility of pleural fluid parameters as prognosticators of complicated parapneumonic effusions that require drainage. OBJECTIVES: The purpose of this prospective study is to further assess the utility of these parameters in the management of a larger series of parapneumonic effusions and to determine appropriate binary decision thresholds. METHODS: We studied 238 consecutive patients with parapneumonic effusions who underwent diagnostic thoracentesis. RESULTS: We found that pleural fluid pH had the highest diagnostic accuracy (area under the curve, AUC: 0.928; 95% confidence interval, CI: 0.894-0.963) compared with pleural fluid glucose (AUC: 0.835; 95% CI: 0.773-0.897), LDH (AUC: 0.824; 95% CI: 0.761-0.887) or pleural fluid volume (AUC: 0.706; 95% CI: 0.634-0.777). The optimal binary decision threshold for pleural fluid pH identifying complicated effusions requiring drainage was 7.15. Binary, multilevel and continuous likelihood ratios (LRs) for pH were calculated to estimate the likelihood of complication of the pleural effusion. Values for the LRs were compared for each of the three strategies, and relative clinical and statistical significances were assessed. Binary LRs provided significantly less information than continuous strategies. CONCLUSION: The pH has the highest diagnostic accuracy for identifying complicated parapneumonic pleural effusions. The binary decision threshold determining the need for chest drainage is 7.15 in our patient series. We recommend continuous LRs to estimate the post-test probability of the complication as they provide the most information compared with binary LRs. Our results do not support the use of pleural fluid LDH as independent predictor of complicated parapneumonic effusions.

Diagnostic value of adenosine deaminase in nontuberculous lymphocytic pleural effusions.

Adenosine deaminase (ADA) can aid in the diagnosis of tuberculous pleural effusions, but false-positive findings from lymphocytic effusions have been reported. The purpose of this study is to assess the ADA levels in nontuberculous lymphocytic pleural effusions (lymphocyte count > 50%) of different aetiologies. Altogether, 410 nontuberculous lymphocytic pleural fluid samples were consecutively selected. These included malignant effusions (n = 221), idiopathic effusions (n = 76), parapneumonic effusions (n = 35), postcoronary artery bypass graft surgery effusions (n = 6), miscellaneous exudative effusions (n = 21) and transudative effusions (n = 51). The ADA level reached the diagnostic cut-off for tuberculosis (40 U x L(-1)) in seven of the 410 cases (1.71%). The negative predictive value of ADA for the diagnosis of pleural tuberculosis was 99% (403 of 407 cases) in the group of lymphocytic pleural effusions. In five of these seven patients ADA1 and ADA2 were measured, and in all these cases (100%) ADA1/ADA(p) correctly classified these lymphocytic effusions as nontuberculous (ratio < 0.42). This prospective study provides additional evidence that adenosine deaminase levels in nontuberculous lymphocytic pleural effusions seldom exceed the cut-off set for tuberculous effusions. The pleural fluid adenosine deaminase levels were significantly higher in different types of exudative effusions than in transudates. An adenosine deaminase level < 40 IU x L(-1) virtually excluded a diagnosis of tuberculosis in lymphocytic pleural effusions. Adenosine deaminase1/adenosine deaminase(p) correctly classified all nontuberculous lymphocytic pleural effusions with high adenosine deaminase levels.

Neumotórax masivo bilateral / Bilateral massive pneumothorax

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Empiema bacteriano espontáneo / Spontaneous bacterial empyema

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Valor de las lipoproteínas en el diagnóstico diferencial de los derrames pleurales / Value of lipoproteins in the differencial diagnosis of pleural effusions

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[Comparative analysis of Light's criteria and other biochemical parameters to distinguish exudates from transudates]. / Análisis comparativo de los criterios de Light y otros parámetros bioquímicos para distinguir entre exudados y trasudados.

Light's criteria have classically been used to differentiate exudates from transudates. Nevertheless, a number of studies have attempted to identify more efficient parameters. The objective of our study was to determine the usefulness of biochemical parameters to differentiate transudates from exudates, and to compare them with the so far best studied criteria: the Light's criteria. We prospectively analysed 850 non selected cases of pleural effusion, with closed final diagnosis after its confirmation, therapeutic response and follow-up, collected consecutively at the Pleura Unit of our hospital. The parameters evaluated as potentially discriminatory between transudates and exudates included: glucose, proteins, albumin, lactate-dehydrogenase (LDH), cholesterol, triglycerides, bilirubin, alkaline phosphatase and adenosin-deaminase (ADA), both separately and in combination to obtain the highest yield. The highest diagnostic yield was observed with the combination of pleural cholesterol, pleural LDH, and the pleural fluid/serum protein ratio, but without significant differences between combinations of pleural cholesterol and LDH, pleaural LDH and pleural proteins, Light's criteria or modified Light's criteria. We recommend the use of pleural cholesterol higher than 47 mg/dl and pleural LDH higher than 222 IU/l to offer the same yield as the combination of three parameters, due to its lower cost and because the necessity of serum determinations is avoided.

Análisis comparativo de los criterios de Light y otros parámetros bioquímicos para distinguir entre exudados y trasudados / Comparative analysis of Light criteria and other biochemical parameters to distinguish exudates from transudates

Los criterios de Light han sido empleados clásicamente para diferenciar entre exudados y trasudados pleurales. No obstante, son muchos los estudios que han tratado de identificar parámetros más eficaces. El objetivo de nuestro trabajo fue determinar la utilidad de distintos parámetros bioquímicos para diferenciar entre trasudados y exudados y compararlos con los criterios mejor estudiados hasta el momento: los criterios de Light. Analizamos prospectivamente 850 casos de derrame pleural no seleccionados, con diagnóstico final cerrado tras su confirmación, respuesta terapéutica y seguimiento, recogidos de forma consecutiva en la Unidad de Pleura de nuestro hospital. Los parámetros que valoramos como potencialmente discriminantes entre trasudados y exudados fueron: glucosa, proteínas, albúmina, lactato deshidrogenasa (LDH), colesterol, triglicéridos, bilirrubina, fosfatasa alcalina y adenosín de aminasa (ADA), tanto individualmente como combinados entre sí para obtener el máximo rendimiento. El mayor rendimiento diagnóstico lo ofrece la combinación del colesterol pleural, la LDH pleural y la relación proteínas pleura/suero, pero sin diferencias significativas con las combinaciones del colesterol y LDH pleurales, la LDH y proteínas pleurales, los criterios de Light o los criterios de Light modificados. Recomendamos el empleo de colesterol pleural mayor de 47 mg/dl y LDH pleural mayor de 222 UI/l por ofrecer el mismo rendimiento que la combinación de tres parámetros, por su menor coste y porque evita la necesidad de determinaciones séricas (AU)

Factores predictivos de engrosamiento pleural en la pleuritis tuberculosa / Factors predictive of pleural thickening in tuberculous pleuritis

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Diagnóstico radiológico / Radiologic diagnosis

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Tromboembolia pulmonar asintomática en pacientes con trombosis venosa profunda

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ADA1/ADAp ratio in pleural tuberculosis: an excellent diagnostic parameter in pleural fluid.

We analysed the efficacy of pleural adenosine deaminase (ADAp) and the ADA1/ADAp ratio in the diagnosis of pleural tuberculosis in 103 pleural effusions, 27 of which were tuberculosis (TB) and 76 other diagnoses (non-TB). Smears, cultures and pleural biopsies were carried out in all cases, and were used for final diagnosis. The diagnostic yield of the parameters under study were as follows: smears/cultures of mycobacteria in fluid 11.1%/33.3%; biopsy 33.3%/51.8% and tuberculosis granulomas 85.1%. The levels of ADAp and ADA1/ADAp ratio in TB and non-TB groups showed very significant differences (P < 0.00001); in the TB group: ADAp 54.7 +/- 23.5 IU and ADA1/ADAp 0.27 +/- 0.08; in the non-TB group: ADAp 18.3 +/- 43.2 IU and ADA1/ADAp 0.64 +/- 0.14. The assay established ADA levels in pleural fluid > or = 40 IU and an ADA1/ADAp ratio < or = 0.42 as cut-off levels to identify individuals in the TB group, with a sensitivity of 88.8%/100%, a specificity of 92%/98.6%, a positive predictive value (PPV) of 80%/96.4%, a negative predictive value (NPV) of 95.8%/100% and an accuracy of 91.2%/99.02%. The ADAp levels in 27 patients with TB, showed close correlation with the number of monocyte macrophages (P = 0.001), but not with the number of lymphocytes (P = n.s.). The ADA1/ADAp ratio overcomes the limitations of ADAp (false positives and negatives), and is the most useful parameter for diagnosis on account of a high diagnostic yield, low cost and speed of the assay for identifying a pleural tuberculosis diagnosis, when compared with traditional methods.

[Pleural eosinophilia: its diagnostic and prognostic significance]. / Eosinofilia pleural: significado diagnóstico y pronóstico.

Pleural eosinophilia (PE) has been usually associated with a good prognosis. Trying to clarify the diagnostic and prognostic significance of those effusions, we studied 50 consecutive PE from our Pleural Unit. Forty four of them met criteria of exudate and six of transudate. PE was significantly more frequent in traumatic pleural effusions, and less frequent in malignant and parapneumonic effusions. There were not statistical differences in the number of malignant effusions associated or not with eosinophilia. We conclude that the presence of pleural eosinophilia is an useful parameter to exclude tuberculous pleural effusions, but not to lessen the likelihood of malignancy. Pleural eosinophilia in an idiopathic pleural effusion means a good prognosis.