A Case of Pleural TB

Abstract

SESSION TITLE: Other Infections SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Extra-pulmonary Tuberculosis (TB) comprises a quarter of the initial TB presentations but can be challenging to diagnosis. Reactivation of latent TB infection (LTBI) is seen in the immunocompromised population. Initial screening for TB with tuberculosis skin test (TST) can be falsely negative in them. Interferon gamma release assay (IGRA) is now the preferred TB screening test. CASE PRESENTATION: 43-year-old male with history of Crohn’s disease with negative TST on adalimumab and mercaptopurine presented with progressively worsening shortness of breath, fevers, night sweats, productive cough and pleuritic chest pain for three weeks duration. He was seen by his primary care physician and given azithromycin for bronchitis. However, symptoms persisted prompting an ER evaluation. He was found febrile, tachycardic, tachypneic and hypoxic. On exam he had diminished breath sounds and dullness to percussion of the right lung field. Chest x-ray showed large right pleural effusion. Laboratory studies were unremarkable. He was started on antibiotics for pneumonia with parapneumonic effusion. A thoracentesis showed exudative fluid process. The adenosine deaminase (ADA) level was low and bacterial culture was negative. However, his Quantiferon test was positive. He continued to worsen so he underwent video-assisted thoracotomy with pleural biopsy given concern for TB. He was found to have numerous pleural implants. The tissue culture was positive for acid fast bacilli. The pathology of the pleural biopsies showed multiple non-necrotizing epithelioid granulomata with histiocytes and giant cells. He was started on RIPE therapy for extra-pulmonary TB. DISCUSSION: Extrapulmonary TB can present as primary TB or in reactivation of LTBI. Tuberculous pleuritis develops from direct infection of the pleura and lymph nodes as a result of a ruptured sub-pleural caseous area in the lung. A delayed hypersensitivity reaction ensues resulting in the development of a tuberculous pleural effusion. In these cases, TB can be detected by sampling the pleural fluid. The pleural fluid has lymphocyte pre-dominance and elevated ADA level. The reliability of this biomarker in detecting TB depends on the prevalence of TB in the area. ADA levels can be falsely low in the early part of tuberculous pleurisy and in the immunocompromised. CONCLUSIONS: This case highlights the high false negative rate of TST among immunosuppressed individuals due to anergy. Our patient was initially tested for TB with TST while on oral steroids during a Crohn's flare. This test was false negative. He had underlying LTBI that became reactivated while on immunosuppressive therapy. IGRA testing would have been a more sensitive method of detecting LTBI. This case also emphasizes the gold standard of diagnosing extra-pulmonary TB with thoracotomy and pleural biopsy. Reference #1: Vorster M., et al. Tuberculous pleural effusions: advances and controversies. Journal of Thoracic Disease. 2015; 7(6): 981-91. DISCLOSURE: The following authors have nothing to disclose: Rohini Manaktala, Ricardo Perez, Prashant Grover No Product/Research Disclosure Information