A case of acute abdomen as the sole presenting feature of odontogenic descending necrotizing mediastinitis: a diagnostic pitfall

Descending necrotizing mediastinitis (DNM) is a rare, life-threatening infection in which a dental or oropharyngeal source of infection spreads along the deep cervical fascial planes into the mediastinum. We report an unusual presentation in which DNM manifested as an acute abdomen with peritoneal signs and was recognized only after a negative laparotomy. A previously healthy 38-year-old man presented with 12 hours of severe abdominal pain and a 10-day history of untreated toothache and facial swelling (prehospital delay). He had fever, tachycardia, generalized guarding, rebound tenderness, and absent bowel sounds (peritonism). Emergency laparotomy, performed without cross-sectional imaging, found no intra-abdominal pathology. Persistent fever prompted re-examination of the neck and CT about 15 hours after the laparotomy (in-hospital interval), which showed an odontogenic abscess extending below the carina in the anterior mediastinum (Endo type IIA), with left pleural empyema and a minimal pericardial effusion. Management included cervicotomy with upper mediastinal drainage, dental extraction, chest tube drainage, and antibiotics. A residual anterior mediastinal collection was drained percutaneously on day 3; transthoracic debridement was deferred because of septic shock and multiorgan failure and was never performed. Septic thrombophlebitis of the internal jugular vein developed, and a collection along the great vessels of the neck was found but not drained; the patient died on day 5 of refractory septic shock with multiorgan failure. In patients with an unexplained acute abdomen, particularly when dental or cervical symptoms are present, an extra-abdominal source should be considered and neck and chest imaging obtained early.