Hemothorax is a collection of blood in the space between the chest wall and the lung (the pleural cavity).

Causes, incidence, and risk factors

The most common cause of hemothorax is chest trauma. Hemothorax can also occur in patients with lung or pleural cancer, or in patients with a defect of the blood clotting mechanism.

The condition is also commonly linked with thoracic or heart surgery, and can also occur in patients who suffer pulmonary infarction (death of lung tissue).

In blunt chest trauma, a rib may lacerate lung tissue or an artery, causing blood to collect in the pleural space. In penetrating chest trauma, a weapon such as a knife or bullet lacerates the lung.

A large hemothorax is often a cause of shock in a trauma victim. Hemothorax may also be associated with pneumothorax (air trapped in the pleural cavity). Depending on the amount of blood or air in the pleural cavity, a collapsed lung can lead to respiratory and hemodynamic failure (tension pneumothorax).

Hemothorax can also be a complication of tuberculosis.


  • Chest pain  
  • Shortness of breath  
  • Respiratory failure  
  • Rapid heart rate  
  • Anxiety  
  • Restlessness

Signs and tests

A physical examination reveals decreased or absent breath sounds on the affected side. Signs of hemothorax may be seen on the following tests:

  • Chest X-ray  
  • Thoracentesis  
  • Pleural fluid analysis


The objective of treatment is to stabilize the patient, stop the bleeding, and remove the blood and air in the pleural space. A chest tube is inserted through the chest wall to drain the blood and air, and it is left in place for several days to re-expand the lung. The cause of the hemothorax should be also treated. However, in trauma patients, depending on the severity of the injury, chest tube drainage is often all that is necessary, and surgery is often not required.

Expectations (prognosis)

The outcome depends on the underlying cause of the hemothorax and the promptness of the treatment.


  • Shock  
  • Fibrosis or scarring of the pleural membranes  
  • Death

Calling your health care provider

Call 911 for any penetrating or serious blunt injury to the chest, or if chest pain or shortness of breath occur.

Go to the emergency room or call the local emergency number (such as 911) if severe chest pain, severe difficulty breathing, absent breathing, and/or other symptoms of hemothorax occur.


Use safety measures (such as seat belts) to avoid injury. Depending on the cause, a hemothorax may not be preventable.

Johns Hopkins patient information

Last revised: December 4, 2012
by Harutyun Medina, M.D.

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