SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pharmacologic inhibition of tumor necrosis factor-alpha (TNF-a) is a mainstay in the treatment of autoimmune disease. Guidelines recommend starting TNF-a antagonists after a negative screening test result for tuberculosis (TB) infection is confirmed, due to the increased risk of reactivation TB in an immunosuppressed host. We present the case of a patient on adalimumab who developed extrapulmonary TB and immune reconstitution inflammatory syndrome (IRIS) after starting TB treatment. CASE PRESENTATION: A 67-year-old woman with a history of psoriasis, on adalimumab therapy for one year, presented to our hospital with chills, fevers, and a non-productive cough for one month. She denied hemoptysis and night sweats but acknowledged a 30-pound weight loss over the prior two months. On presentation, she was afebrile, normotensive, saturating 95% on room air. Chest X-ray was notable for bilateral miliary nodules and CT scan showed extensive miliary lesions in her lungs and spleen. She was admitted to the medicine service and put on airborne isolation. Interferon-gamma release assay (IGRA) and testing for HIV were negative. Induced sputum was collected, acid-fast bacilli (AFBs) were noted on smear microscopy, and PCR-based assay confirmed presence of Mycobacterium tuberculosis (MTb). Mycobacterial blood cultures were sent. Anti-TB therapy was started, and she was discharged to home isolation. One month later, she re-presented with dyspnea on exertion. Repeat CT scan showed a large left pleural effusion and a small pericardial effusion. AFB stain and culture of pleural fluid was negative. Repeat sputum AFB stain and culture was also negative, and MTb was not detected by PCR. Prior blood cultures resulted as positive for MTb. She was discharged home after clinical improvement with resolution of her dyspnea. DISCUSSION: TB is one of the top 10 causes of death worldwide. 20% of patients with active TB can have false negative IGRAs, especially if immunosuppressed. IRIS, most often seen in HIV+ patients, can develop with TB treatment initiation. Paradoxical worsening of clinical status occurs as the depressed immune system begins to recover. Patients on TNF-a antagonists are also at risk for IRIS, more commonly in lung and extrapulmonary TB. Thus, the combination of TNF-a antagonist discontinuation and TB treatment placed our patient at heightened risk for IRIS. CONCLUSIONS: This case demonstrates TB dissemination in an immunocompromised patient on a TNF-a antagonist who developed IRIS with adalimumab cessation and TB treatment initiation. Among commonly used biologic agents, adalimumab has been associated with a greater risk for both TB infection and IRIS development after starting TB treatment. Clinicians should be aware of this risk and monitor patients accordingly once treatment is initiated. Reference #1: World Health Organization. Global tuberculosis report 2019. Geneva, Switzerland: World Health Organization; 2019. Reference #2: Dobler, C. C. (2016). Biologic agents and tuberculosis. Microbiology Spectrum, Dec; 4(6). Reference #3: Cheng, V. C. et al. Clinical spectrum of paradoxical deterioration during antituberculosis therapy in non-HIV-infected patients. Eur. J. Clin. Microbiol. Infect. Dis. 21, 803–809 (2002). DISCLOSURES: No relevant relationships by Mark Adelman, source=Web Response No relevant relationships by Vickie Kassapidis, source=Web Response