Tracheoesophageal fistula demarcates an open connection between the esophagus and the trachea. It is frequently associated with esophageal atresia, while malignant diseases of the esophagus and instrumentation are other notable factors. Aspiration of gastric contents, coughing after swallowing and frequent pneumonia are reported symptoms. The diagnosis is made by either bronchoscopy or barium esophagography. Surgical management is necessary in all patients.
Increased rate of respiratory secretions and reflux of gastric content is frequently observed in patients on mechanical ventilation , while recurrent pneumonia as a result of aspiration and sepsis, a potentially life-threatening complication, may occur. Chronic cough that is aggravated by ingestion of liquids is considered to be one of the main distinguishing features of TEF , while dysphagia is reported in isolated cases .
Making an early diagnosis is detrimental in achieving good patient outcomes. The first step is a detailed physical examination, together with fully obtained patient history that may reveal key details regarding symptoms and comorbidities. In neonates and infants, the diagnosis can be confirmed early on through ultrasonography, while more invasive methods are required in adults. Plain radiography and CT have shown to be useful adjunctive methods, but a more specific diagnostic procedure, such as bronchoscopy or esophagoscopy is considered as gold standard . CT-guided esophagoscopy, however, has also proven to be a technique that yields very good results . Its use, however, has been questioned when it comes to determining the optimal surgical approach , which is one of the main goals of imaging studies apart from confirming the presence of a fistula.
Initial management include palliative measures, but because median survival time without surgery is estimated to be between 1 and 6 weeks , this form of therapy needs to be conducted rapidly. Various methods exist and are used depending on the subtype and severity of the malformation. The goal of surgical treatment is to eliminate further contamination of the respiratory system, reestablish food passage and restore adequate nutrition. The two most effective methods have shown to be esophageal bypass and stenting . Bypass is considered to be a more demanding surgical procedure, while stenting is indicated in patients of all age groups . Esophageal exclusion, resection and repair of the fistula, as well as chemotherapy and radiation in the case of malignancy are additional approaches . To minimize gastric reflux and prevent further malnutrition, gastrostomy and jejunostomy may be performed, respectively.
Advances in surgical and postoperative care have significantly improved the outcome of patients with tracheoesophageal fistulas , but the prognosis still significantly depends on the underlying cause and precipitating factors that led to its development. Neonates and infants in whom a congenital diagnosis is made have very good recovery rates with early and adequate surgical management, while patients in whom TEF arises due to malignant disease, the prognosis is extremely poor . Median survival rate is only months after surgery, while persistent fistulas have an even worse prognosis . In addition to the predisposing etiology, the promptness of making the diagnosis is also considered as a significant prognostic factor, as respiratory symptoms may significantly impair the quality of life and cause more harm to the patient if TEF is not revealed in its early stages .
Congenital forms of TEF are almost universally associated with esophageal atresia, a malformation of the esophagus that develops during embryonic life . The exact cause, however remains unknown, but environmental and genetic factors have been listed as potential factors in the pathogenesis . Acquired TEF, on the other hand, is seen in patients suffering from malignant diseases such as esophageal carcinoma and lung cancer, while approximately 1% of patients in whom tracheostomy is performed develop TEF as a result of damage caused by prolonged intubation .
When TEF is associated with esophageal atresia, incidence is approximately 1 in 3500 live births and up to 50% of newborns have additional anomalies, including vertebral, cardiovascular, renal, musculoskeletal and several other . Tracheostomy carries a very small risk of TEF development (< 1%), but it is one of the most important risk factors for acquired forms . Additional risk factors are airway infection, oxygen deprivation, diabetes mellitus and poor nutrition , whereas both environmental and genetic factors have been implicated. Exposure to diethylstilbestrol and methimazole, but also alcohol and tobacco during pregnancy are listed as a significant risk, whereas a myriad of genetic diseases, such as Down syndrome, Edwards syndrome, Patau syndrome, Feingold syndrome, Opitz syndrome, DiGeorge syndrome, Fanconi anemia and many other have been observed in patients with TEFs . Some reports have shown that up to 17% of children suffering from this condition were diagnosed with eosinophilic esophagitis, but its connection to TEF remains to be discovered . Significant airway anomalies, including laryngomalacia, subglottic stenosis, tracheomalacia and vocal fold paresis, have been detected in some studies .
Congenital development of TEF and esophageal atresia occurs during the fifth week of embryonic life, when the trachea and the esophagus arise from the foregut . Normally, the mesenchymal tissue situated between the two tubes should separate them, but for some reason, incomplete separation occurs and various subtypes can be encountered. The distal or proximal portion of the esophagus may be connected to the trachea (atresia with distal or proximal fistula, respectively), while approximately 4% of congenital forms include both proximal and distal attachment . In rare cases, isolated forms (H type) may be seen and they are considered to be least severe . On the other hand, mechanical damage to the trachea and esophagus in the setting of malignancy or instrumentation is considered to be one of the most important factors. Regardless of the underlying mechanism of development, symptoms and complications stem from compromise of the respiratory tree by food and gastric contents as a result of reflux . As a result, aspiration pneumonia and life-threatening sepsis may occur and symptoms such as coughing and increased secretions are triggered so that gastric content is expelled from the trachea.
Since the exact mechanism of TEF development remains unknown, prevention of morbidity and disability caused by this condition can be achieved by making the diagnosis while being in its initial stages.
Tracheoesophageal fistula (TEF) is an anatomical malformation that results in direct communication between the esophagus and the trachea. It can arise from either congenital or acquired causes. Esophageal atresia, one of the most common gastrointestinal anomalies, is seen in up to 98% of all congenital TEFs and various subtypes exist . The most common is atresia with distal fistula, in which the proximal part of the esophagus is not connected to the distal part that arises from the trachea directly. Atresia with proximal fistula, atresia with double fistula and isolated esophageal changes are other congenital forms . On the other hand, malignant tumors such as esophageal carcinoma, intubation and tracheostomy may provoke the formation of this anatomical entity  . Factors that have shown to increase the risk of TEF development comprise inadequate nutrition, infection of the airways, hypoxemia, anemia, diabetes mellitus, corticosteroid therapy and hypotension . Maternal alcohol consumption and smoking, as well as exposure to methimazole (used for hyperthyroidism) and diethylstilbestrol potentially increase the rates of TEF . Genetic factors also play a potential role, as 50% of patients in whom esophageal atresia is present have other accompanying anomalies, such as cardiovascular, renal, gastrointestinal and cerebral, as well as limb and vertebral defects . Although various risk factors and predisposing conditions have been identified, the exact cause of TEF remains incompletely understood. Congenital development of TEF occurs at some point during the fifth week of gestation, when the foregut differentiates into the esophagus and trachea . Mucosal ischemia, abrasion and mechanical injury to the trachea is the presumed pathogenic mechanism of acquired TEF . Patients experience increased respiratory secretions, aspiration of gastric contents and consequent pneumonia that is often recurrent and severe . Some reports indicate that frequent coughing after swallowing liquids is one of the hallmarks of this condition . The diagnosis of congenital TEF is made by ultrasonography in utero or during neonatal period, while bronchoscopy and esophagoscopy are principal methods used in adult patients . Computed tomography (CT) has shown to be of benefit in some patients . Treatment invariably includes a surgical approach in all patients and methods such as tracheal reconstruction, use of stents and fistula repair are applied . The prognosis significantly varies depending on the underlying cause, as congenital forms are managed efficiently, whereas malignant TEF is associated with an extremely poor prognosis .
Tracheoesophageal fistula (TEF) is a condition where the trachea, the tube through which air travels into the lungs, and esophagus, through which food passes into the stomach, are connected. It is often encountered in neonates and infants, in whom the cause is incomplete separation during embryonic life, in which case it is closely associated with esophageal atresia, one of the most common congenital malformations of the gastrointestinal tract. In adults, esophageal and lung cancer may promote formation of the fistula, while intubation and tracheostomy have shown to be one of the most important risk factors. Diabetes mellitus, infections of the respiratory tract and numerous genetic diseases have been brought into connection with this anatomical malformation, but the exact mechanism of disease remains unknown. Symptoms appear as a result of aspiration of food into the respiratory system and recurrent pneumonia, increased respiratory secretions, cough after swallowing and poor nutrition are most frequently reported. To make the diagnosis, ultrasonography may be sufficient in infants and young children, while use of more invasive methods such as bronchoscopy may be necessary in adults. However, either computed tomography (CT scan), guided or direct inspection of the esophagus (esophagoscopy), is considered to be the procedure of choice. Regardless of the predisposing factor that led to TEF formation, surgery is necessary in all patients, as survival rates are measured in weeks without appropriate treatment. It is important to prevent further passage of food into the lungs and restore adequate nutrition, which may sometimes require insertion of tubes through the abdomen and into the stomach (gastrostomy) or small intestine (jejunostomy). Abolishing the connection between the trachea and the esophagus is the main goal of surgical treatment and various techniques, including use of stents, resection and repair of the fistula are used. The prognosis significantly depends on the underlying cause. Infants and young children are effectively treated, while in patients in whom a malignant disease provoked the formation of TEF, survival rates range from weeks to months. Nevertheless, the importance of an early diagnosis is detrimental, since significant damage of the respiratory tree may be prevented by identifying this condition in its early stages.