Posted by Kayla in Esophageal Atresia | 0 Comments
Esophageal Atresia/Tracheoesophageal Fistula
Although the recorded history of esophageal atresia (EA) and tracheoesophageal fistula (TEF) dates back to the 17th century, surgical treatment for these anomalies was not suggested until 1869. In 1939, Leven1 and Ladd2 independently completed the first successful treatments for EA; Haight performed the first successful primary repair 2 years later.EA is a condition in which the proximal and distal portions of the esophagus do not communicate. The upper segment of the esophagus is a dilated, blind-ending pouch with a hypertrophied muscular wall that typically extends to the level of the second to fourth thoracic vertebra. The distal esophageal portion is an atretic pouch with a small diameter and a thin muscular wall; it extends a variable distance above the diaphragm. TEF is an abnormal communication between the trachea and esophagus. When associated with EA, the fistula most commonly occurs between the distal esophageal segment and the trachea, just above the carina. An “H-type” TEF is a TEF without EA. Although they can occur at any level between the cricoid cartilage and the carina, TEFs usually course obliquely (with the tracheal end proximal) at or above the level of the second thoracic vertebra. Five types of EA and TEF have been described. The most common abnormality is EA with a distal TEF (84%). Isolated atresia with no fistula is the next most common finding (8%), followed by H-type TEF (no atresia) (4%). EA with proximal and distal fistulas (3%) and EA with a proximal fistula (1%) are less common. The frequencies given for each type are calculated from a summary of 6 long-term studies. However every esophageal atresia case is different. You will not find one case exactly the sane as the other even though it my be type c it could be type c but with out long gap or type c with a fistula or with out or type c with down syndrome or all the things above so really when it is just 5 known types there are actually tons.
Etiologies and factors
The etiologies of EA and TEF are still largely unknown, but many theories concerning their origins have been proposed. The trachea and esophagus are foregut derivatives. During the fourth gestational week, lateral mesodermal ridges form in the proximal esophagus; the fusion of these grooves in the midline separates the esophagus from the trachea around the 26th day of gestation.Notochord abnormalities, desynchronous esophageal mesenchymal and epithelial growth rates, neural crest cell involvement, and incomplete tracheoesophageal separation resulting from a lack of apoptosis are some of the conditions theorized for EA embryogenesis. Similarly, incomplete tracheoesophageal septation, lateral ridge fusion failure, and tracheal and esophageal proximity have been suggested as possible explanations for the origin of TEF. In addition, vascular insufficiencies; genetic factors; vitamin deficiencies; drug and alcohol exposures; and viral, chemical, and external physical events may contribute to the development of EA and/or TEF. According to these theories, several factors appears to alter the rate and timing of cell growth and proliferation in the embryonic foregut. These events most likely occur before the 34th day of gestation. Other organs, such as the remainder of the intestinal tract, the heart, the kidneys, the ureters, and the skeletal system, are also developing around this time, and they are vulnerable to developmental irregularities as well.
Pathophysiology Because of a discontinuous esophagus, infants with EA cannot clear their secretions. This defect leads to persistent drooling and aspiration or regurgitation of food after attempted feedings. TEF causes additional complications as a result of the communication between the trachea and the esophagus. When infants with TEF strain, cough, or cry, air enters the stomach through the fistula. As a result, the stomach and small intestine can become dilated, which elevates the diaphragm and makes respiration more difficult. Reflux of food and gastric secretions through the fistula into the tracheobronchial tree and up the esophagus may also occur; this reflux can contribute to pneumonia and atelectasis. Therefore, pneumonia and respiratory distress are common complications of TEF. Abnormal esophageal motility has been observed in children with EA and/or TEF. Often, controversy exists as to whether the abnormality is inherently present in the child’s esophagus or if EA and/or TEF develops as a result of the surgical treatment. Manometric studies have shown that the motility disorder is present before surgical treatment. Animal studies have also shown that esophageal transection followed by repair does not precipitate disturbances in motility. Discoordinated peristalsis has been reported from the level of the fistula to the stomach in patients with cases of isolated TEF.
