A case report showing the diagnostic challenges for pleural tuberculosis

SESSION TITLE: Chest Infections Case Report Posters 11 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 02:10 pm - 02:55 pm INTRODUCTION: Pleural tuberculosis (TB) accounts for 3-25% of all TB cases. In some cases diagnosis can be challenging when initial results are non-diagnostic. We discuss a case of pleural TB where initial pleural testing was negative, and the diagnosis was subsequently made on repeat investigations, after empiric therapy was started given the high index of suspicion. CASE PRESENTATION: A 74-year-old Hispanic female was admitted to the hospital with worsening dyspnea, tachypnea and hypoxia. CXR showed a pleural effusion involving nearly the entire right hemithorax (Figure 1). She underwent thoracentesis and chest tube insertion. Pleural fluid analysis was consistent with exudative effusion with a lymphocyte predominance and negative for culture and malignancy. Adenosine deaminase (ADA) was 29 IU/L. Chest tube was removed 6 days later when fluid was adequately drained.Subsequently, pleural fluid reaccumulated requiring robotic assisted right lung decortication, pleurectomy, pleurodesis and repeat chest tube placement. Operative fluid was again exudative with LDL 731 U/L but again negative for culture, including mycobacteria, or malignancy. Pleural tissue pathology showed marked non-caseating and focal areas of caseating granulomas. Her course was further complicated by a massive hemothorax requiring an emergent surgical intervention.The patient immigrated to the United States from Puerto Rico at age 20 with no travel in the prior 10 years. She had a past medical history of untreated latent tuberculosis. Given the high suspicion of pleural TB, rifampin, isoniazid, pyrazinamide, ethambutol and pyridoxine were initiated. Fluid samples collected during the hemothorax drainage subsequently tested positive for TB by PCR and culture, demonstrating susceptibility to first line drugs. Initial samples from the prior thoracentesis and first decortication yielded no growth. DISCUSSION: Pleural TB diagnosis can pose challenges when diagnostic tests are inconclusive. The yield of AFB microscopy of pleural fluid is about 5-10% whereas culture has sensitivity of 24-58%, taking several weeks to grow. ADA levels >40 IU/L have sensitivity 81-100% and specificity 83-100%. Nucleic acid amplification testing (NAAT) of the fluid is highly specific but 25-62% sensitive and has the advantage of providing information on rifampin genotypic resistance. In our case, initial pleural fluid was exudative and lymphocytic but low ADA and negative smear and cultures. Even fluid sent during decortication yielded no growth despite tissue showing pathologic granulomas. Only with repeated fluid sampling from a second emergent surgery, the culture and PCR tested positive for TB. Pleural biopsy is the most reliable diagnostic method but is invasive, operator-dependent and carries a risk for complications. NAAT of both pleural fluid and tissue should be considered, unlike in our patient where only the fluid was sent during initial surgery. CONCLUSIONS: Additional diagnostic tools such as VATS for pleural biopsy, repeated sampling and NAAT may be needed while facing diagnostic challenges. With high clinical index of suspicion the importance of empiric therapy of TB cannot be emphasized enough while awaiting results. Early therapy may expedite clinical response and shorten the duration of contagiousness, which has infection control and public health value. Further studies are needed to improve the diagnostic work up in pleural TB. REFERENCE #1: Castro DJ, Nuevo GD, Pérez-Rodríguez E, Light RW. Diagnostic value of adenosine deaminase in nontuberculous lymphocytic pleural effusions. Eur Respir J. 2003;21(2):220-224. doi:10.1183/09031936.03.00051603 REFERENCE #2: Jiang J, Shi HZ, Liang QL, Qin SM, Qin XJ. Diagnostic Value of Interferon-γ in Tuberculous Pleurisy: A Metaanalysis. CHEST. 2007;131(4):1133-1141. doi:10.1378/chest.06-2273 REFERENCE #3: Vorster MJ, Allwood BW, Diacon AH, Koegelenberg CFN. Tuberculous pleural effusions: advances and controversies. J Thorac Dis. 2015;7(6):981-991. doi:10.3978/j.issn.2072-1439.2015.02.18 DISCLOSURES: No relevant relationships by Ayah Alkhidir No relevant relationships by Mubashir Ayaz Ahmed No relevant relationships by Andranik Bedross No relevant relationships by Shayet Hossain Eshan No relevant relationships by Sami Hussein No relevant relationships by Zahin Islam Rafa No relevant relationships by Nnenna Uzodi No relevant relationships by Hina Wazir No relevant relationships by Mitchell Weinstein