Nonspecific Pleural Effusion vs Malignant and Granulomatous Pleural Disease
We have read with interest the retrospective study by Leslie et al (Chest 1988; 94:603-08) on the clinical features of patients with undiagnosed pleural effusions subjected to repeat pleural biopsies with the purpose of distinguishing those patients with nonspecific pleuritis (NPE) from malignant (MPE) or tuberculous pleural eflusions (TPE). According to their analysis, all patients having two or more of the following factors should undergo an aggressive diagnostic approach given the likelihood of underlying malignant or granulomatous disease: weight loss, fever >38°C, positive PPD, pleural fluid lymphocytosis greater than 95 percent, and a large efiusion.
We have studied all patients with pleural eflusions seen at our institution from October, 1987 to February, 1989. We applied the criteria proposed by Leslie et al and, in addition, we have considered another parameter—pleural adenosine-deaminase activity (ADA). Eighty-one patients (30 with TPE, 37 with MPE and 14 with NPE) were included. In general, our results are very similar to those of Leslie et al. When one criterion was present, sensitivity and specificity for granulomatous or malignant disease were 92 and 35 percent, respectively, and 62 and 71 percent when two or more criteria were present. PPD status did not have a good discriminatory power, since we found a higher percentage of positives in patients with MPE and NPE than that found by Leslie et al. This could be related to the higher prevalence of tuberculosis in our community.
On the other hand, a high pleural ADA was found to be an excellent indicator for tuberculous pleuresy, with sensitivity of 96.5 percent and specificity of 94 percent, as recently reported by others. This is an easy and inexpensive enzyme determination that we think should be done in all undiagnosed pleural eflusions; in our milieu, and by itself, it offers much more information in the diagnosis of TPE than the five criteria considered by Leslie et al. canadian discount drugs
Also, and differing from the work of Leslie et al, when we compared the clinical characteristics of NPE vs MPE we found that abnormal chest radiograph (without considering the calcified lesions) was significantly more frequent in MPE (64 percent) than in NPE (14 percent) (p<0.005, x2 =10.25). These differences could be the selection related to the population studied by Leslie et al. Within their NPE group, they included a significant number of patients with heart failure who had an initial pathologic chest x-ray film that subsequently normalized following diuretic treatment. It has been our experience and that of others2 that the presence of abnormalities of the pulmonary parenchyma should lead us to suspect a malignant process, particularly if pleural ADA determination is negative; therefore, an aggressive diagnostic approach (including bronchoscopy) should be recommended.