Bronchopleural fistula

Bronchopleural fistulas are communications between the bronchial tree and the pleural space.  

Clinical features

A bronchopleural fistula is usually diagnosed at 1 week to 3 months post lobectomy or pneumonectomy, most commonly between 8 to 12 days post operation ¹².

A central bronchopleural fistula is usually suspected in the early postoeprative period. It can be diagnosed easily by bronchoscopy or after a large air leak ¹².

A peripheral bronchopleural fistula can be suspected when there is an air leak, prolonged pneumothorax with air-fluid level within pleural effusion or empyema, history of needle or drainage tube insertion into the thorax, presence of gas-producing bacteria or aspiration pneumonia due to backflow of pus from empyema into the bronchial tree ⁹.

Pathology

They are usually divided as ²:

• central: when the fistula involves the trachea or a lobar bronchus
• peripheral: when a distal airway, either segmental bronchi or the lung parenchyma, communicates to the pleural space

Etiology

• postoperative complication of pulmonary resection: considered by far the most common cause, with a reported incidence from 1.5 to 28% after pulmonary resection ¹
  • may rarely be caused by pleuroparenchymal fibroelastosis ⁸
• lung necrosis complicating infection or infarction
  • tuberculosis ⁴
• traumatic
  • pneumatoceles 
  • iatrogenic (eg. thoracic tube insertion, lung biopsy, thoracocentesis, and nasogastric tube malpositioning)
• lung neoplasms
  • tumor extension into the pleural space
  • tumor necrosis after chemotherapy or radiotherapy

Radiographic features

Plain radiograph

On chest radiography, the features that may be seen include:

• steady increase in intrapleural air
• appearance of a new intrapleural gas-pleural fluid collection - i.e. a hydropneumothorax. The gas-fluid level typically extends to the chest wall and shows unequal linear dimensions on orthogonal views conforming to the pleural space
• changes in an already present gas-fluid level
• development of tension pneumothorax
• a drop in the gas-fluid level exceeding 2 cm (if the patient has no chest tube in place)

CT

CT is considered the imaging technique of choice for visualizing and characterizing bronchopleural fistulae ². CT may show:

• pneumothorax
• hydropneumothorax
• pneumomediastinum
• underlying lung pathology
• demonstration of an actual fistulous communication 

Nuclear medicine

Radioaerosol scanning (e.g. xenon ventilation nuclear scintigraphy) has been successfully used in the evaluation of bronchopleural fistulas ^5-7. A variety of radioactive tracers may be used, including:

• technetium-99m (Tc-99m) albumin colloid fog inhalation
• Tc-99m sulfur colloid
• Tc-99m labeled diethylenetriamine pentaacetate, krypton, and xenon
• single photon emission tomography using radiolabeled aerosol inhalation. If there is fistula the radioactive tracer will equilibrate between the postpneumonectomy or pleural space and the airways after inhalation