Buffalo pneumothorax

A buffalo pneumothorax (or buffalo chest) refers to the rare occurrence of bilateral pneumothoraces caused by an abnormal physical communication between the two pleural spaces. The pleuropleural communication is postulated to be in the anterior median chest where there is a loss of the normal anatomical separation of the two pleural spaces at the anterior junctional line.

The presence of separate right and left pneumothoraces simultaneously is an extremely rare occurrence and a pleuropleural communication should be suspected.

Clinical presentation

The presentation can be worse than that of unilateral pneumothorax of the same size, including severe and sudden onset of dyspnea and pleuritic chest pain, tachycardia and hypotension. If sufficient tension pneumothorax develops, in which the patient may suffer cardiac arrest and death.

Pathology

There are numerous causes which have been described in case reports :

• iatrogenic (most common)
  • surgery (recent and distant)
    • mediastinal surgery
    • heart-lung transplant
    • pneumonectomy
    • esophagectomy
  • catheter insertion such as central venous catheter (CVC) and intercostal catheter (ICC)
  • lung biopsy
  • thoracocentesis
  • mechanical ventilation
• chest trauma, e.g. rib fractures
• pectus excavatum
• congenital due to anatomic variation: complete or fenestrated pleuropleural communication
• respiratory disease
  • COPD: particularly emphysematous bulla rupture
  • cystic fibrosis (CF)
  • asthma

Radiographic features

Plain radiograph and CT

The features of buffalo chest are identical to unilateral pneumothorax except for being bilateral. Due to the bilateral nature, there may be competing mass effect in the chest resulting in minimal or even no mediastinal shift. But if the amount of air in the 'combined' pleural space is significant enough tension physiology may be present.

There may be signs which indicate a possible cause such as:

• sternal wires indicating recent thoracotomy
• rib fractures or other findings of chest trauma
• endotracheal tube for ventilation
• unilateral pleural catheter
• other lines and tubes
• respiratory diseases such as COPD, asthma or CF findings

Treatment and prognosis

Theoretically, the placement of a unilateral pleural catheter should decompress the bilateral pneumothoraces. Some, however, have been treated with bilateral pleural drainage.

History and etymology

Buffalo species have a single contiguous pleural cavity containing both lungs. When hunting American buffalo, native American Indians would shoot a single arrow into the chest of the beast which "would probably cause both lungs to collapse, rendering the animal incapacitated" .

Sheep and mules have also been reported to have similar anatomy, and some horses may have ventral pleural fenestrations.