Abstract Introduction There has been an increasing prevalence of Nontuberculous mycobacteria (NTM) and Tuberculosis (TB) in the UK. Extra-pulmonary NTM disease is usually limited to lymph node, skin and soft tissue or skeletal infections. Pleural involvement is more common in TB compared to NTM especially in immunocompetent individuals. It is often difficult to distinguish during initial investigations. There are limited cases with varying reports regarding the management and prognosis of NTM disease with pleural involvement. Case report A 90-year-old Caucasian male presented with one month history of breathlessness and productive cough with weight loss. CT thorax confirmed left sided hydropneumothorax with loculated effusion (Figure 1). There was multiple nodular opacity bilaterally with multiple cavitating lesions. An intercostal drain was inserted, and initial pleural microscopy and culture did not show any significant growth, and fluid acid-fast bacilli (AFB) was smear negative. Subsequent sputum AFB were smear positive on three consecutive samples with negative molecular amplification test. Two QuantiFERON tests were indeterminant. Further pleural fluid AFB demonstrated negative smear but positive culture after 5 days of incubation. Fluid adenosine deaminase (ADA) was elevated at 76. He was initiated on TB treatment due to the presentation with pleural disease and positive AFB cultures on both sputum and pleural fluid. However, due to significant rise in liver enzymes and intolerance, treatment was suspended. AFB culture identification eventually confirmed Mycobacterium avium growth in all samples. Due to significant side effects, after several discussions with the patient, the decision was to not initiate further treatment. Upon clinic review after 3 months, he was clinically stable and had resumed daily activities of living with stable weight. Discussion Pleural involvement of NTM is a rare presentation for immunocompetent individuals without pre-existing respiratory conditions. AFB culture identification can take up to 12 weeks. In combination of the history, radiology and initial microbiology and multiple indeterminate QuantiFERON results prompted the initiation of TB treatment. It often presents as a diagnostic challenge when patients present with lymphocytic pleural effusion, especially if pleural biopsy or thoracoscopy is deemed high risk in more frail populations. Whilst fluid ADA is a useful tool, it cannot be used in isolation to diagnose TB or NTM. There are promising results shown for specific biomarkers including IL-27 and Mtb HspX protein which provides promising specificities. Further research is required to improve the accuracy and time to diagnosis of pleural TB and NTM disease to improve patient experience and outcome. This abstract is funded by: None
Lu et al. (Fri,) studied this question.