Case Report Of A Large Cavitary Pulmonary Lesion In Mycobacterium Avium Complex Infection

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: The most common nontuberculous mycobacterial (NTM) infections are caused by Mycobacterium avium complex (MAC) [1], which are a ubiquitous bacteria that can be found in soil and water. Those affected with MAC pulmonary disease are more likely to have a history of underlying lung disease or immunosuppression, and some studies have shown that patients with rheumatoid arthritis (RA) are at higher risk of developing NTM disease [2]. Additionally, cavitary lesions are an important finding in MAC pulmonary disease, and cavity size and consolidation may have a relationship with disease progression [1]. This report illustrates a MAC pulmonary infection presenting with a large cavitary lesion in a patient with sarcoidosis and RA-associated interstitial lung disease (ILD). CASE PRESENTATION: A 69-year-old Hispanic male presents with three months of productive cough, fatigue, and unintentional 20-pound weight loss. His medical history includes sarcoidosis and RA-associated ILD on azathioprine and hydroxychloroquine, and previously treated latent tuberculosis. A chest computed tomography (CT) reveals a new area of consolidation in the lateral segment of the right middle lung lobe associated with a 7 x 7 cm area of thick-walled cavitary consolidation. A bronchoscopy with bronchoalveolar lavage and transbronchial biopsy results in M. avium complex infection and necrotizing granulomas. DISCUSSION: There have been few studies on NTM infections in RA patients, and there appears to be an increased incidence of such infections in this immunocompromised population, and especially among those with concomitant history of tuberculosis and ILD [2]. Additionally the finding of large cavities has been proposed to be a predictor of high rates of mortality and respiratory failure, and could therefore give some insight into disease management [1]. Historically, MAC pulmonary infection was treated with anti-tuberculosis drugs, such as isoniazid, rifampin and ethambutol, which proved to be largely ineffective until the introduction of macrolides clarithromycin and azithromycin. Current guidelines favor macrolides with rifampin and ethambutol as first-line regimen, with the addition of aminoglycosides such as amikacin or streptomycin in severe disease [3]. In this case, our patient was asked to discontinue azathioprine, and will begin first-line therapy with consideration for use of aminoglycosides given his presentation with a large cavitary lesion. CONCLUSIONS: This case highlights a MAC pulmonary infection in an immunocompromised patient with sarcoidosis and RA-associated ILD presenting with a large cavitary lesion, which may be a predictor of disease progression. Reference #1: Oshitani Y, Kitada S, Edahiro R, et al. Characteristic chest CT findings for progressive cavities in Mycobacterium avium complex pulmonary disease: a retrospective cohort study. Respir Res. 2020;21(1):10. Reference #2: Lim D-H, Kim Y-G, Shim TS, et al. Nontuberculous mycobacterial infection in rheumatoid arthritis patients: a single-center experience in South Korea. Korean J Intern Med. 2017;32(6):1090-1097. Reference #3: Haworth CS, Banks J, Capstick T, et al. British Thoracic Society guidelines for the management of non-tuberculous mycobacterial pulmonary disease (NTM-PD). Thorax. 2017;72(Suppl 2):ii1-ii64. DISCLOSURES: No relevant relationships by Jeff Kwon, source=Web Response No relevant relationships by Sandra Patrucco Reyes, source=Web Response