Objective: To evaluate the diagnostic yield of bronchoscopy and mediastinoscopy in adults with isolated mediastinal tuberculous lymphadenitis and to assess the effect of antituberculous treatment.
Design: Prospective longitudinal cohort study of 34 patients with mediastinal tuberculous lymphadenitis followed for 6 to 19 months after completion of treatment.
Setting: Tertiary care hospital, Kuwait.
Patients: 34 consecutive patients who presented with isolated mediastinal lymphadenopathy from 1996 to 1998.
Interventions: Bronchoscopy and cervical mediastinoscopy for all patients.
Main outcome measures: Diagnostic yield of bronchoscopy and mediastinoscopy, and the outcome of treatment in patients with tuberculous lymphadenopathy.
Results: The mean age was 35 years (range 15-58). The most common symptoms were cough, fever, and weight loss. The chest radiographs and computed tomograms showed abnormal mediastinal shadows with no evidence of parenchymal disease. All patients had right sided paratracheal lymphadenopathy. Tuberculin skin test gave a weal of >15 mm in 17 patients (50%). Sputum smears and cultures failed to grow acid-fast bacilli in any patient. Seven patients had an endobronchial abnormality and samples taken at bronchoscopy gave a definite diagnosis in 3 (9%). Paratracheal lymph node biopsy and culture by mediastinoscopy diagnosed tuberculosis in all cases. All patients were treated by a six month course of rifampicin and isoniazid supplemented initially by pyrazinamide for two months. Twenty-eight patients had a good response and the remaining patients were treated for a further 3 months.
Conclusions: Bronchoscopy has a low diagnostic yield in mediastinal tuberculous lymphadenopathy in the absence of a parenchymal lesion. Mediastinoscopy is a safe but invasive procedure and provides a tissue diagnosis in most cases. Six months treatment with rifampicin and isoniazid supplemented initially by pyrazinamide is adequate treatment for most adults with tuberculous mediastinal lymphadenopathy.