Acute mediastinitis

  • rare but life threatening
  • high morbidity and mortality
  • most common causes: post op complications, esophageal perforation (Boerhaave syndrome)
  • Esophageal perforation usually occurs just above gastro esophageal junction
  • leakage from esophagus due to a necrotic neoplasm
  • extension of infection from neck, retroperitoneum or intrathoracic structures
  • ill, high fever, tachycardia, chest pain
imaging
Chest Xray
  • widening, ill-defined mediastinal outline
  • streaks or collections of air within mediastinum
  • mediastinal air-fluid levels
  • air in soft tissues of neck
  • pleural effusions frequent and on the left
  • often lower lobe pneumonia or atelectasis
  • esophagogram with water soluble contrast identifies site of leak
CT
  • optimal technique
  • increased attenuation of mediastinal fat
  • free gas bubbles in mediastinum
  • localized fluid collections
  • enlarged lymph nodes
  • pleural effusions
  • empyema
  • subphrenic or pericardial collection may or may not be present
  • In post op cases – distinguishing retrosternal hematoma from reactive granulation tissue or cellulitis difficult
  • substernal fluid collections, pockets of air normal in first 20 days post sternotomy