Tracheoesophageal fistula caused by ingestion of a caustic substance. (Imaging Clinic).

A 16-year-old girl was brought to the emergency room after she had attempted suicide by ingesting drain cleaner that contained the caustic substance sodium hydroxide. Despite appropriate medical treatment, 1 week later the patient developed a persistent cough, especially after swallowing. Helical computed tomography (CT) of the neck and chest with three-dimensional reconstruction detected an abnormal communication between the trachea and the esophagus that was consistent with a tracheoesophageal fistula.

A tracheoesophageal fistula is an uncommon clinical problem with several possible etiologies: congenital abnormality, malignancy (e.g., lung carcinoma, lymph node metastasis, or esophageal carcinoma), complication of radiotherapy, trauma to the respiratory tract or esophagus (e.g., from endoscopic instrumentation), blunt or penetrating trauma, surgical trauma, foreign-body perforation, contact with a corrosive substance, postemetic rupture, infection, and inflammation.

The common initial signs of a tracheoesophageal fistula are a sudden cough associated with ingestion of fluids or solids (Ono's sign), (1) the production of sputum mixed with food, recurrent pulmonary infections, weight loss, and profound weakness. (2) Although most of the acquired tracheoesophageal fistulas are secondary to malignancy or iatrogenic procedures, a fistula caused by a caustic substance is an important finding in any patient who has a history of toxicity with these substances, especially children.

The imaging method of choice for the evaluation of a tracheoesophageal fistula is an oral contrast study of the esophagus. Meglumine diatrizoate is used in upper gastrointestinal examinations when a perforation is suspected. The positive sign for tracheoesophageal fistula is the passage of the contrast media from the esophagus to the trachea, with or without delineation of the fistulous communication. (2) In oblique projections of the upper thorax, the pattern of contrast media in the esophagus, trachea, and fistulous tract can resemble the letter H, especially in patients with congenital fistulas. (3)

CT has proven to be valuable in the evaluation of the trachea and esophagus when a trachecesophageal fistula is suspected. Thin-section helical CT images are used to evaluate the tracheal and esophageal walls. If there is an anomalous communication between these two structures, the wall defect can be identified. Three-dimensional reconstructions and virtual endoscopy can also be helpful in identifying these lesions. In cases of a large communication, a unique lumen develops from the previously normal airway and upper gastrointestinal tract (figure).

References

(1.) Gerzic Z, Rakic S, Randjelovic T. Acquired benign esophagorespiratory fistula: Report of 16 consecutive cases. Ann Thorac Surg 1990;50:724-7.

(2.) Gudovsky LM. Koroleva NS, Biryukov Y, et al. Tracheoesophageal fistulas. Ann Thorac Surg 1993;55:868-75.

(3.) Grainger RG, Allison DJ, Adam A, Dixon AK, eds. Grainger and Allison's Diagnostic Radiology. A Textbook of Medical Imaging. 4th ed. London: Churchill Livingstone, 2001:647-8.

From the Department of Radiology, Louisiana State University Health Sciences Center, New Orleans.