Visual Diagnosis of Pleural Tuberculosis and its Association with Tissue Biopsy, Culture and Xpert Assay.

INTRODUCTION: The diagnosis of pleural tuberculosis remains a clinical challenge due to the paucibacillary nature of disease. Medical thoracoscopy remains the gold standard in diagnosing tuberculous pleuritis. OBJECTIVE: To establish the diagnostic yield of sago-seed thoracoscopic appearance of pleura in tuberculosis and its correlation with histopathology, tissue AFB culture and tissue Xpert MTB/Rif assay. METHODS: All consecutive patients with lymphocytic exudative pleural effusion, who fulfilled inclusion criteria of the study underwent medical thoracoscopy under local anesthesia and pleural tissue was sent for histopathology, AFB culture and Xpert MTB/Rif assay. Chronic granulomatous inflammation on histopathology and response to anti-tuberculous treatment was taken as reference standard for diagnosis of tuberculous pleurisy. RESULTS: A total of 249 patients were included in the study, out of which 168 had effusion secondary to tuberculosis. Sago-like nodules visualized on thoracoscopy had a sensitivity of 58.9 %, specificity of 92.6 % and diagnostic accuracy of 69.88 % for pleural tuberculosis. There is a strong association between the presence of sago-like nodules and detection of mycobacterium tuberculosis on Xpert MTB/Rif assay and AFB culture of pleura (p-value 0.007). CONCLUSION: Sago seed nodules on pleura have a high positive predictive value for tuberculous pleurisy. In high endemic countries patients with this finding on thoracoscopy can be commenced on anti-tuberculous treatment before histopathology or culture results are available.

Diagnostic implications of bronchial lavage in patients with pleural tuberculosis.

INTRODUCTION: The presence of Mycobacterium tuberculosis in a respiratory specimen is diagnostic in patients with pleural effusion. It is difficult to obtain sputum even after induction in these patients. An alternative method of acquiring respiratory specimens is via bronchial lavage. This study was undertaken to evaluate the diagnostic yield of acid-fast bacilli (AFB) smear, AFB culture, and Xpert assay of bronchial lavage fluid in the workup of pleural tuberculosis patients. MATERIAL AND METHODS: All patients who met the inclusion criteria of the study underwent thoracentesis, pleural biopsy, and bronchial lavage. Specimens of pleural fluid, pleural biopsy, and bronchial lavage fluid were sent for acid fast bacilli smear, culture, and Xpert assay. RESULT: Bronchial lavage AFB smear, culture, and Xpert assay was positive in 9.5%, 17.9%, and 26.2% of patients, respectively. It gave an immediate diagnosis in 22 (26.2%) patients. CONCLUSION: Bronchial lavage, though not a surrogate to pleural biopsy, offers an additional approach to the early diagnosis of pleural tuberculosis in patients not producing sputum. Besides being diagnostic, this method also has epidemiologic significance in containing the tuberculosis epidemic because detecting Mycobacterium in bronchial lavage confirms that the patient is infectious.

Comparison between the diagnostic accuracy of Xpert MTB/Rif assay and culture for pleural tuberculosis using tissue biopsy.

BACKGROUND: Early diagnosis of pleural tuberculosis is difficult as it is a paucibacillary disease and a combination of tests is required to diagnose it, which have varied diagnostic accuracy and increase the cost. The aim of this study was to evaluate the diagnostic performance of the Xpert MTB/Rif assay on thoracoscopic pleural biopsy specimens. METHODS: A total of 201 patients with exudative pleural effusion and normal lung parenchyma were included in the study. All patients underwent thoracoscopic pleural biopsy under local anaesthesia. Biopsy samples were sent for Xpert MTB/Rif assay and culture, along with histopathology. Chronic granulomatous inflammation on histopathology and response to antituberculous treatment was taken as the reference standard for diagnosis of tuberculous pleurisy. RESULTS: Of the 198 patients included in the final analysis, 134 had pleural tuberculosis. The sensitivity of the Xpert assay was 52.2% and specificity was 100%, and that of pleural biopsy cultures were 41% and 100% respectively. CONCLUSION: The sensitivity and specificity of Xpert MTB/Rif assay scores were high, hence escalating the speed of diagnosis and imparting marked impact on patient outcomes. The Xpert MTB/Rif assay is a potential game changer in diagnosing pleural tuberculosis.