A haemothorax (plural: haemothoraces), or rarely haematothorax, literally means blood within the chest, is a term usually used to describe a pleural effusion due to accumulation of blood. If a haemothorax occurs concurrently with a pneumothorax it is then termed a haemopneumothorax. 

A tension haemothorax refers to haemothorax that results from massive intrathoracic bleeding, causing ipsilateral lung compression and mediastinal displacement ⁹.

Clinical presentation

Haemothoraces usually present with dyspnoea or thoracic pain. Patients typically have a history of trauma or malignancy.

Complications

Complications that can occur after a retained haemothorax include ⁷:

• infection

  • empyema formation

  • pneumonia

• chronic fibrothorax

Pathology

A haemothorax is sometimes defined as pleural fluid with a haematocrit ≥50% of the peripheral blood haematocrit.

Aetiology

• traumatic haemothorax

  • usually occurs from penetrating or blunt trauma ³ to the chest

• non-traumatic (spontaneous haemothorax) ⁸

  • intrathoracic malignancy

    • usually occurs with thoracic wall tumours

      • thoracic wall schwannomas

      • thoracic wall neurofibromas

    • soft-tissue tumours 

      • sarcomas: thoracic angiosarcomas

    • hepatocellular carcinomas: with thoracic invasion or thoracic metastases

    • lung cancer: is uncommon cause even in the setting of pleural extension ⁸

  • spontaneous pneumothorax - spontaneous haemopneumothorax

  • anticoagulant medication

  • vascular rupture

    • aortic dissection

    • rupture of coronary arteries such as RCA during an angioplasty

    • thoracic arteriovenous malformations

      • pulmonary arteriovenous malformation ¹⁰

    • thoracic endometriosis

    • pulmonary infarction

    • pleural adhesions with pneumothorax

    • haematologic abnormalities: coagulopathy

      • haemophilia

  • connective tissue disease

    • Ehlers-Danlos syndrome (EDS) type IV: in the setting of internal mammary artery rupture

  • congenital bony exostoses

• iatrogenic: thoracentesis, central venous catheterisation and thoracotomy ¹³

Classification

The severity of haemothorax in an adult patient ¹³:

• minimal: <400 mL

• medium: 400 to 1000 mL

• massive: >1000 mL

Radiographic features

Plain radiograph

Chest radiographic appearance of a large haemothorax may be similar to that of a pleural effusion. It can be almost impossible to differentiate a haemothorax from other causes of pleural effusions.

Ultrasound

Ultrasound has a very high sensitivity (92%), specificity (100%), positive predictive values (100%), and negative predictive values (98%) for the detection of a haemothorax in the context of preceding trauma ². Sonographic features characteristic, albeit nonspecific, of haemothoraces include ¹²:

• homogenously echogenic effusion

  • typical of haemothoraces in the acute stage

• plankton sign 

• haematocrit sign ¹¹

  • implies collection has been present for a longer period of time

  • the cellular component may layer in the posterior costophrenic recess, creating an interface with the superficial anechoic layer

CT

CT is useful in determining the nature of the pleural fluid in the setting of trauma by assessing the attenuation value. Blood in the pleural space typically has an attenuation of 35-70 HU ⁶. Pleural fluid attenuation measurement should be routine in the interpretation of chest trauma CT to distinguish simple fluid from acute blood.

In the setting of trauma, there may be other ancillary features such as pulmonary contusions and lacerations.

Treatment and prognosis

The exact management strategy will depend on the underlying aetiology. In general, drainage is performed for symptomatic therapy.

For a clotted haemothorax options include:

• video-assisted thoracoscopic surgery (VATS)

• intrapleural fibrinolytic therapy (IPFT)