Endobronchial ultrasound for tubercular mediastinal adenopathy and its comparison with traditional tools

SETTING: Endobronchial ultrasound (EBUS) is now the preferred tool to sample malignant mediastinal lesions. Data on its role in tubercular mediastinal adenopathy are limited.OBJECTIVE: To evaluate the efficacy of EBUS in diagnosing tubercular mediastinal lymphadenopathy and correlate the cytological and microbiological results obtained on aspirate with standard methods (radiology and the tuberculin skin test) suggesting tuberculosis (TB).DESIGN: A prospective study of 125 patients with suspected tubercular mediastinal lymphadenopathy who underwent EBUS-transbronchial needle aspiration. Only patients with a microbiologically confirmed diagnosis or unequivocal clinico-radiological response to anti-TB treatment during follow-up were included.RESULTS: A total of 122 patients showed findings suggesting TB on cytopathology (sensitivity 97.6%), 105 (84%) of whom had microbiological evidence of TB (positive smear/culture or both). Performing staining for acid-fast bacilli on slides prepared during the procedure vs. only on samples submitted in saline significantly improved the yield. Only 92 patients (73.6%) were Mantoux-positive. Cytology was more sensitive than computed tomography in picking up necrosis. Granulomas, with or without necrosis, were equally likely to be microbiologically positive. However, presence of only necrosis in a TB-endemic region invariably points towards TB diagnosis.CONCLUSIONS: EBUS was highly sensitive and specific for diagnosis of mediastinal TB and may be considered the investigation of choice for tubercular mediastinal adenopathy.