A70-21 Difficult Diagnosis of Culture Negative Pleural Tuberculosis Presenting as Massive Pleural Effusion

Abstract Tuberculous pleural effusion is an uncommon manifestation of mycobacterial infection, accounting for approximately 3-5% of cases in the United States. Identifying tuberculosis infection as the cause of a patient’s pleural effusion is especially challenging due to the low yield of conventionally used microbiological testing. We present a case of culture-negative active pleural tuberculosis diagnosed after extensive microbiological workup and surgical biopsy. A 30-year-old male with a history of cerebral palsy, seizure disorder, and diabetes presented from group home due to complaints of dyspnea, cough, and malaise. Initial chest x-ray revealed near complete opacification of the right hemithorax. CT of the chest revealed atelectatic lung collapse and a lytic lesion of the T7 vertebrae. Thoracentesis was performed, draining 2,580 mL of amber fluid. A thoracostomy tube was placed shortly thereafter, immediately draining an additional 1500 mL of blood-tinged fluid. MRI of the T7 vertebral lesion was concerning for neoplastic process, but CT-guided biopsy demonstrated granulomatous inflammation without evidence of neoplasm. Extensive microbiological testing, including culture and staining of the blood, fluid, and bone, serological testing for markers of Coccidioides, Histoplasmosis, Blastomyces, Aspergillus, viral infection, and interferon-gamma release assay (IGRA), remained negative. Additional pleural fluid testing revealed an adenosine deaminase level of 45 U/L. Suspicion of mycobacterial infection prompted video assisted thoracic surgery for pleural biopsy, followed by decortication for trapped lung caused by a 1-inch thick fibrothorax. Mediastinal lymph node and lung biopsies were also performed. Findings of necrotic granulomatous disease in the lung and pleural tissue further raised suspicion of active tuberculosis. IGRA was found to be strongly positive upon repeat testing. Anti-tubercular therapy was initiated. The patient was discharged on the 60th day of admission. Nucleic acid amplification testing (NAAT) of biopsy tissue confirmed the diagnosis.Conventional microbiological testing such as cultures, sputum acid-fast smear, and acid-fast staining provide far less diagnostic value in cases of extrapulmonary tuberculosis in comparison to typical intrapulmonary infection. Our case highlights the high level of clinical suspicion required to diagnose pleural tuberculosis, supports the utilization of tissue biopsy and NAAT for definitive diagnosis, and serves as a cautionary example of the risk of prolonged hospital stay due to delayed diagnosis. This abstract is funded by: None