A buffalo pneumothorax refers to the rare occurrence of simultaneous bilateral pneumothoraces made possible by interpleural fenestrations connecting the right and left pleural cavities. Most cases of human bilateral pneumothorax are iatrogenic due to surgical disruption of the pleura ⁹. Bilateral tension pneumothorax can be rapidly fatal.

Epidemiology

Interpleural communications are known to occur in mammals including buffalo, dogs, cats, horses and rabbits ⁹. A study of eight slaughtered buffalo found interpleural fenestrations in four ⁹. A review of 47 reported cases in humans identified ⁹:

• 31 cases following cardiothoracic surgery

• 7 cases following thoracic intervention (lung biopsy, chest drain, central line, tracheostomy or pacemaker)

• 4 cases of spontaneous pneumothorax (some followed mechanical ventilation)

Diagnosis

A suspicion of bilateral pneumothorax can be confirmed by CXR.

Clinical presentation

Bilateral tension pneumothorax rapidly increases bilateral intrapleural pressure causing chest expansion, pulmonary atelectasis, obstruction of venous return and circulatory collapse. Immediate placement of bilateral chest drains can be life-saving. IV cannulae can be placed prior to formal chest drainage and air can be aspirated.

Pathology

The embryology is similar in all mammal species, and it is likely that apoptosis affecting the pleura at points of contact along the anterior or posterior junction lines could cause fenestration.

There are numerous case reports describing various causes^1-8:

• iatrogenic (most common)

  • surgery (recent and distant)

    • mediastinal surgery

    • heart-lung transplant

    • pneumonectomy

    • oesophagectomy

  • 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 that there may be competing mass effect resulting in minimal or even no mediastinal shift. But if the amount of air in the 'combined' pleural space is large 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

Unilateral or bilateral pleural drainage may suffice depending on the size of each pneumothorax. A high proportion of patients may require VATS pleurodesis and/or bullectomy ¹⁰.

History and etymology

The term ‘buffalo chest’ can be traced to a single anecdote relating how native Americans could shoot a single arrow into the chest of the North American bison which “would probably cause both lungs to collapse, rendering the animal incapacitated" ^5,9.