Bronchoesophageal fistula

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Thoracic radiograph of a dog with bronchoesophageal fistula, showing a soft tissue opacity affecting the accessory lung lobe[1]

Primary bronchoesophageal fistula or tracheoesophageal fistula are a congenital disease of dogs characterized by an abnormal connection between the respiratory system and esophagus.

Acquired fistulas have also been reported due to esophageal foreign body ingestion[2] and invasive esophageal or bronchial carcinoma.

This condition usually arises as a result of an aberrant formation of the respiratory tract from the embryologic digestive tract and a predisposition has been reported in the Cairn Terrier.

Bronchoesophageal fistulas usually communicate with the left caudal lung lobe in dogs (although other lung lobes have been reportedly affected). The fistulas may also be associated with esophageal diverticula (congenital or acquired).

Clinical symptoms usually occur in young, small-breed dogs and include chronic coughing and regurgitation, often aggravated by eating or drinking. In dogs with anorexia, fever and lethargy, secondary pneumonia may also be present[3].

A tentative diagnosis is usually based on presenting clinical signs, radiography and exclusion of lung parasites such as heartworm disease and pulmonary interstitial fibrosis.

Radiography usually reveals an esophageal diverticulum, regional megaesophagus and focal interstitial densities in the right caudal and middle lung lobes. Using fluoroscopy and contrast radiography, contrast material may be seen accumulating in the diverticulum and refluxing into the right middle, caudal, and accessory bronchi[4]. Use of a small amount of barium is recommended as iodinated contrast agents are hyperosmolar and can cause pulmonary edema.

A differential diagnosis would include ciliary dyskinesia, cricopharyngeal achalasia, esophagitis, megaesophagus and elongated soft palate in brachygnatic dogs.

Treatment is curative with surgical intervention in cases of congenital or foreign-body fistulas, consisting of a lung lobectomy and repair of the defect in the esophagus using a lateral thoracotomy approach.

With invasive neoplasia, surgical intervention, such as surgical resection/repair of the fistula carries high mortality and morbidity[5].

References

  1. Della Ripa, MA et al (2010) Canine bronchoesophageal fistulas: Case report and literature review. Compendium 32(4)'
  2. van Ee RT et al (1986) Bronchoesophageal fistula and transient megaesophagus in a dog. J Am Vet Med Assoc 188(8):874-876
  3. Merck Vet Manual
  4. Basher AW et al (1991) Surgical treatment of a congenital bronchoesophageal fistula in a dog. J Am Vet Med Assoc 199(4):479-482
  5. Burt M et al (1991) Malignant esophagorespiratory fistula: management options and survival. Ann Thorac Surg 52:1222–1228