AN UNUSUAL CASE OF NECROTIZING BACTERIAL MEDIASTINAL AND HILAR LYMPHADENITIS

Abstract

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Mediastinal and hilar lymphadenopathy is seen in various pulmonary pathology. Lymphadenopathy can often be reactive, associated with chronic inflammatory states or infections (1). However, necrosis and microabscesses of mediastinal lymph nodes due to bacterial infection, in the absence of lung parenchymal infection, is rare. CASE PRESENTATION: A 32 year-old female with incidental finding of mediastinal and right hilar lymphadenopathy on CT scan that had initially remained stable for 2 years on surveillance imaging presented with shortness of breath. Repeat imaging showed worsening of the known right hilum node and infracarinal node compressing the airway. Endobronchial Ultrasound guided Transbronchial Needle Aspiration (EBUS-TBNA) of station 7 and 11Rs lymph nodes reported acellular necrotic debris. Tissue and bronchoalveolar lavage cultures grew alpha hemolytic Streptococcus. She was treated with a 1 week course of augmentin. She presented approximately a month later with complaints of fever, chills and a cough productive of thick brownish sputum. Chest X-ray and CT showed further worsening of thoracic lymphadenopathy. Sputum and blood cultures were negative. HIV screen, RPR, TB T-spot test, Histoplasma antigen, serology for Brucella and Toxoplasma were negative. She underwent open thoracotomy with wedge biopsy of the hilar mass by CT Surgery. Pathology showed acute and chronic inflammation, necrotic tissue with microabscesses. Tissue culture grew Staphylococcus epidermidis. Patient completed a three month course of doxycycline with resolution of symptoms and thoracic adenopathy. DISCUSSION: A study by Evision et al of 100 patients with isolated mediastinal and hilar lymphadenopathy undergoing EBUS-TBNA showed that a significant portion of patients had reactive lymphadenopathy and in carefully selected patients with negative results, surveillance rather than further invasive testing was an appropriate strategy(1). In this case, due to clinical and radiographic worsening after EBUS-TBNA, without a clear diagnosis, further invasive testing with surgical biopsy was deemed necessary. Necrotising mediastinal lymphadenopathy due to tuberculosis(2) and sarcoidosis have been reported in literature. There has also been a report of Streptococcus anginosus (viridans group) lymphadenitis(3). This is a case of necrotising mediastinal lymphadenopathy likely caused by alpha hemolytic Streptococcus(without further speciation possible) and Staphylococcal secondary mediastinitis or superinfection, that responded to appropriate antibiotics. CONCLUSIONS: Necrotizing bacterial lymphadenitis can present with enlarging mediastinal lymphadenopathy and infectious symptoms. A more prolonged course of antibiotics is suggested to treat such cases. Reference #1: Evison M, Crosbie PAJ, Morris J, et al. A study of patients with isolated mediastinal and hilar lymphadenopathy undergoing EBUS-TBNA. BMJ Open Respiratory Research 2014;1:e000040. doi:10.1136/bmjresp-2014-000040 Reference #2: Iyengar, K. B., Kudru, C. U., Nagiri, S. K., & Rao, A. C. (2014). Tuberculous mediastinal lymphadenopathy in an adult. BMJ case reports, 2014, bcr2013200718. https://doi.org/10.1136/bcr-2013-200718 Reference #3: Cho A.H., Alwassia A., Abaalkhail N., Khosla R. An unusual case of Necrotic Mediastinal Lymphadenopathy. American Journal of Respiratory and Critical Care Medicine 2020;201:A6037. DISCLOSURES: No relevant relationships by Rishi Arora, source=Web Response No relevant relationships by David Chambers, source=Web Response No relevant relationships by UZAIR GHORI, source=Web Response No relevant relationships by Sania Jiwani, source=Web Response