Odontogenic Infection Complicated By Descending Necrotizing Mediastinitis And Chylothorax

Untreated odontogenic infections may progress to life-threatening descending necrotizing mediastinitis (DNM), with a mortality rate of 20.2%. Although rare, DNM-associated chylothorax can accelerate clinical deterioration. Early recognition of these complications is critical for timely intervention and improved outcomes. A 62-year-old diabetic woman presented with a 4-day history of right submandibular swelling and 1-day dyspnea. Examination revealed fever (38°C), fluctuant bilateral submandibular swelling, and restricted mouth opening. CT showed periapical radiolucency at the right second molar. Emergency incision and drainage improved her breathing. Initial ceftriaxone therapy was escalated to linezolid and meropenem after cultures confirmed multidrug-resistant infection. On day 12, she developed persistent chest discomfort. Contrast CT showed pneumomediastinum and right pleural effusion. Ultrasound-guided thoracentesis drained 500 mL of milky fluid, with positive chylous tests and elevated ADA/LDH, confirming chylothorax. Aggressive drainage, antibiotics, and nutritional support stabilized her condition. DNM, often secondary to odontogenic infections, is an acute suppurative condition with complications like airway obstruction and sepsis. Chylothorax is exceptionally rare, but may occur if infection involves the thoracic duct, causing fluid loss and immunosuppression. Management requires individualized approaches (conservative vs. surgical). In this case, combined antibiotics and drainage achieved control, underscoring the importance of early microbial testing, antimicrobial stewardship and multidisciplinary care for tailored therapy. DNM should be suspected in severe odontogenic infections. Chylothorax, though uncommon, warrants consideration. Multidisciplinary management, targeted antibiotics, and nutritional support are pivotal for recovery.