DESCENDING NECROTIZING MEDIASTINITIS (DNM) DISGUISING AS A MEDIASTINAL MASS

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: DNM is an uncommon infection arising in the head or neck which tracks between cervical fascial planes into mediastinum. We report a case of with challenging presentation. CASE PRESENTATION: A 56-year-old male on chronic hemodialysis recovering from COVID pneumonia, presented to emergency department 2 days shortness breath. He was hypertensive, tachycardic and hypoxic, respiratory distress, requiring immediate initiation noninvasive ventilation. Shortly after arrival, he went cardiac arrest. Resuscitation efforts were successful. Intensive management included mechanical ventilation, broad spectrum antibiotics, vasopressors continuous renal replacement therapy for suspected septic shock. x-ray showed mediastinal widening, confirmed by CT, be due 7.5 cm lobulated, soft tissue density mediastinum impinging trachea. Bronchoscopy via endotracheal tube no obstruction except some dynamic airway collapse. Trans-bronchial needle aspiration mass non-diagnostic. In days, improved, extubated but then emergently re-intubated acute upper obstruction. Repeat imaging revealed large retropharyngeal abscess extending C1 level thyroid gland. It wrapped around anteriorly communicated collection superior surrounding Also noted enlarging pleural effusion. Urgent surgical drainage space, fluid performed. Cultures grew Staphylococcus aureus. Mediastinal exploration tracheostomy followed. steadily improved discharged. DISCUSSION: life-threatening that originates neck; this case. spreads caudally through facilitated gravity negative intrathoracic pressures (1). Oral flora are usual pathogens (2). Diagnosis needs high index suspicion obtain necessary imaging. Favorable outcomes seen early diagnosis, protection, antibiotics timely (3).Our patient had narrowing proximal trachea compression emergent re-intubation. His initial chest CT reported concerning malignancy. second suggested abscess. Looking back, prior x-rays progressive widening over 10 making malignancy less likely. Review old remains invaluable. CONCLUSIONS: Deep leading mediastinitis requires antibiotic administration as well operative source control. REFERENCE #1: Benedetto C, et al. Catastrophic descending necrotizing anterior posterior compartments: report. Radiol Rep. 2020;15(10):1832-1836 #2: Brook I, Frazier EH. Microbiology mediastinitis. Arch Intern Med. 1996 Feb 12;156(3):333-6. Erratum in: Med May 27;156(10):1112. PMID: 8572845. #3: Ridder GJ, Maier W, Kinzer S, Teszler CB, Boedeker CC, Pfeiffer J. Descending mediastinitis: contemporary trends etiology, management, outcome. Ann Surg. 2010 Mar;251(3):528-34. doi: 10.1097/SLA.0b013e3181c1b0d1. 19858699. DISCLOSURES: No relevant relationships Rana Hejal, source=Web Response Willie McClure, Tanmay Panchabhai, Layla Sankari, Apoorwa Thati,