Clinical Profile of Tubercular Empyema with Special Reference to Diagnostic Role of Cartridge Based Nucleic Acid Amplification test (CBNAAT)

Abstract

Introduction: Tuberculosis is continuing to be a significant burden in the developing world and tubercular empyema thoracis still remains a common entity with significant morbidity and mortality. Clinical course of tubercular empyema is often accompanied by bronchopleural fistula, concomitant pulmonary tuberculosis and unfavourable outcome. Aim: A prospective study was conducted to assess the clinical presentation of tubercular empyema with special emphasis on evaluating diagnostic role of Cartridge Based Nucleic Acid Amplification Test (CBNAAT) and outcome issues. Materials and Methods: A prospective study was carried out consisting of adult cases of tubercular empyema admitted in the department of Respiratory Medicine in a teaching hospital in eastern India over a period of 18 months. Tubercular empyema cases were analysed on the basis of clinicoradiological features, diagnostic challenges with special interest on role of newer molecular diagnostic test like CBNAAT, management and outcome issues. Results: A total of 40 cases of tubercular empyema were encountered during the study period. Tubercular empyema frequently affected young population (mean age 31.5 years) with a male preponderance (72.5%). Thirty five (87.5%) patients had a duration of illness of more than one month on presentation. There was frequent accompaniment of concomitant pulmonary tuberculosis (60%) and bronchopleural fistula (42.5%). Sputum smear for acid fast bacilli (55%) and CBNAAT (57.5%) were positive in good number of cases. Pleural fluid smear for acid fast bacilli and CBNAAT yield were also very high (72.5% and 92.5% respectively). Pleural fluid CBNAAT had a sensitivity of 92.5% (95% CI: 79.61-98.43) and specificity of 100% (95% CI: 93.51-100) in diagnosis of tubercular empyema. Mean duration of Intercostal tube drainage was 45.6 days and eighteen patients needed decortication. Conclusion: Tubercular empyema is a disease affecting the young population most commonly, has a chronicity in clinical course and is commonly complicated by presence of associated pulmonary tuberculosis, bronchopleural fistula and unfavourable outcome. Pleural fluid and sputum CBNAAT have good yield in diagnosis.

Keywords

• Bronchopleural fistula
• Decortication
• Rapid diagnostic test
• Thoracic empyema
• Tuberculosis