• Accumulation of blood in the intrapleural space after blunt/penetrating chest trauma or other nontraumatic etiology. Bleeding is usually a result of disruption of the tissues/vessels of the chest wall, pleura, or intrathoracic structures:
    • Results in decreased vital capacity, hypoxia, and respiratory compromise
    • Loss of large intravascular volume results in hemodynamic instability and hemorrhagic shock
    • Massive hemothorax can cause increased intrathoracic pressure, resulting in compromised venous return and decreased cardiac output
  • Rarely a solitary finding in blunt trauma:
    • Commonly associated with pneumothorax (25% of cases), extrathoracic injuries (73% of cases), and pulmonary contusion
  • Large hemothoraces cause the release of substances that can act as anticoagulants and contribute to continued intrathoracic bleeding
  • If left untreated, can lead to empyema and fibrothorax (lung trapping due to adhesions)


  • Traumatic injuries (including iatrogenic) to major blood vessels:
    • Common vessels, including intercostal artery, internal mammary artery, pulmonary artery, pulmonary vein, aorta, vena cava, and heart are associated with hemorrhage into the thoracic cavity
  • Traumatic lung parenchymal injuries:
    • Often stops spontaneously as a result of low pulmonary pressures and high concentrations of thromboplastin in the lung
    • Often associated with pneumothorax
  • Nontraumatic or spontaneous hemothoraces:
    • Very rare
    • Consider coagulation disorder, malignancy, primary vascular event (such as aortic dissection, ruptured aneurysm), PE with infarction, infection (TB), bullous emphysema, pulmonary AV malformation, lobar sequestration
  • Torn pleural adhesions as a complication of spontaneous pneumothorax or tube thoracostomy

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