Acquired tracheo-esophageal fistula

An acquired tracheo-oesophageal fistula refers to a pathological communication between the trachea and oesophagus due to a secondary cause 

Pathology

Acquired causes of tracheo-oesophageal fistulae can be divided into those that are related to malignancy (common) and those from other causes (uncommon).  

Malignancy-related causes:

• malignancy
  • in the elderly, they are most frequently seen with an intrathoracic malignancy and are most commonly associated with malignancy of the oesophagus
  • this is often from malignant tissue spreading to involve the tracheal or bronchial wall and with subsequent ulceration and necrosis of the malignant tissue leading to tissue breakdown and fistula formation.
• radiotherapy

Non-malignant causes: infrequent

• trauma (blunt, penetrating, or iatrogenic):  e.g. gunshot wounds ³
• chronic inflammation: chronic infections - tracheal wall necrosis or necrotising inflammation is usually the cause for fistulization. 
  • tuberculosis
  • histoplasmosis
• post-tracheostomy ²

Radiographic features

Fluoroscopy

May show the site and extent of direct communication in real time. Fluoroscopy allows for dynamic evaluation of oesophageal motility as well as evaluation of its lumen.

CT

A routine CT study could miss fistulae if the fistula tract is collapsed. Therefore a CT oral contrast swallow study is often performed in these situations. A diluted preparation of a non-ionic iodinated contrast agent is recommended with patient given a mouthful bolus of the preparation and asked to swallow it promptly on instruction to do so during the scan. Ct may accurately show the extent of the fistulation as well as complication such as aspiration effects in the lungs.

Differential diagnosis

On imaging consider delayed presentation of a congenital tracheo-oesophageal fistula.