Snapshot A 58-year-old man develops fever, tachycardia, and worsening chest pain 2 days after undergoing a coronary artery bypass surgery for coronary artery disease. On examination, his sternotomy wound is draining purulent fluid. A chest radiograph demonstrates mediastinal widening and a CT scan demonstrates mediastinal gas. Introduction Clinical definition inflammation of the mediastinum types of mediastinitis acute login to view 1 more bullet chronic login to view 1 more bullet Epidemiology Incidence 3% incidence of acute mediastinitis following sternotomy very low incidence of chronic mediastinitis Risk factors recent sternotomy Etiology Pathophysiology mechanism of injury acute login to view 3 more bullets chronic login to view 5 more bullets other infectious causes login to view 6 more bullets pathoanatomy normal anatomy login to view 31 more bullets Presentation Symptoms chest pain fever tachycardia Physical exam purulent discharge from the wound wound erythema sternal tenderness Imaging Radiographs indication should be obtained if mediastinitis is suspected findings mediastinal widening Computerized tomography (CT) indication should be obtained if mediastinitis is suspected findings mediastinal gas and fluid Differential Acute pericarditis distinguishing factor may present with pleuritic chest pain and a friction rub Cardiac tamponade distinguishing factor may present with Beck triad (hypotension, muffled heart sounds, and jugular venous distension) Treatment Operative surgical emergency debridement and broad-spectrum antibiotics Complications Death Prognosis Survival with treatment 40% acute mortality rate with treatment 10-year survival rate is 40%