At the beginning of a pregnancy, the trachea ("windpipe") and the esophagus ("foodpipe") are one single tube, called the primitive foregut*.  Between the 23 ^rd and the 28^th day of pregnancy, a time when many women are not even sure they are pregnant, this single tube divides into two tubes – the trachea, which takes the air you breathe to the lungs, and the esophagus, which takes food, water, and saliva to the stomach.  If something should ever go wrong with this division, as it does in approximately one out of every 3,500 – 4,000 births, the baby is born with a medical condition known as esophageal atresia and/or tracheoesophageal fistula.  The anomalies are thought to arise from 1) a defective division of the primitive foregut into the trachea and esophagus, 2) defective growth of the entodermal* cells leading to atresia, or 3) incomplete fusion of the lateral side walls of the foregut during separation of the trachea from the foregut causing a tracheoesophageal fistula.

Atresia means an absence or closure of an orifice or tubular organ.  In this case, the esophagus has a gap between its upper and lower segments, so that nothing can pass through, not even saliva.  The fistula is a connection between the esophagus and trachea, which, depending on its position, either lets food or acidic stomach juices into the lungs.  When a fetus has esophageal atresia, the inability to swallow and eliminate amniotic fluid may result in polyhydramnios.*  This is the first sign of possible atresia at some level in the upper gastrointestinal tract and may lead to premature birth.

Many babies born with this defect have other medical problems – all associated with organs that were being formed during the same period at the beginning of the pregnancy.  At least 25% of these babies are premature, and 25% have additional critical problems such as congential heart disease, Down's Syndrome*, hydronephrosis*, duodenal atresia*, and tracheomalacia*.  Ten percent of the babies have an imperforate anus*, and one-half have vertebral or skeletal anomalies.  Researchers found that it was not uncommon to have vertebral (V), anal (A), tracheo-esophageal (TE), and/or radial limb or renal (kidney) (R) anomalies, which was abbreviated as VATER syndrome (or VATER association) by Quan and Smith in 1973.  This syndrome is also currently being termed as VACTERL, the C referring to cardiovascular problems, and the L to limb defects, because of the high percentage of children with VATER syndrome born with these latter anomalies.

How is this anomaly discovered?

In type A atresia, both esophageal segments are blind pouches, and neither connected to the trachea.  It maybe termed as pure esophageal atresia and may be considered either short or long gap, depending on the space between the segments.  An infant born with pure esophageal atresia may appear normal at birth, but as they swallow, secretions fill the esophageal pouch, causing an overflow into the oropharynx*, and the infant will drool excessively.  When the infant is fed, vomiting and respiratory distress follow (aspiration).  Continual suctioning temporarily relieves these symptoms.  Both the excessive secretions and drooling in a newborn strongly suggest esophageal atresia.

In type E (or H-type tracheoesophageal fistula without atresia) the fistula may occur anywhere between the level of the cricoid cartilage* and the mid-esophagus.  However, the fistula is usually higher in the trachea than in the esophagus.  A fistula such as this may be as small as a pinpoint.  Symptoms that may signal this H-type fistula are repeated episodes of lung inflammation (pneumonitis), infection of the lungs or respiratory system (pulmonary infection), and swollen abdomen (abdominal distention).  When a child with this disorder drinks, he coughs, chokes, and becomes cyanotic (bluish discoloration of the skin and mucous membranes).  The reasons for this are that excessive mucous builds up in the esophagus, producing abdominal distention.  This type of tracheoesophageal fistula may be overlooked, since such a child may appear normal at birth.  It is possible for diagnosis to be delayed as long as a year.

In types B and D, the upper portion of the esophagus opens into the trachea, a life-threatening condition since an infant with this anomaly can aspirate saliva or food into the trachea.  Both type B (proximal fistula and type D (fistula to both segments) cause immediate inhalation of saliva into the trachea airway and bacterial pneumonitis*.

The most common tracheoesophageal fistula is Type C, which includes esophageal atresia. The upper section of the esophagus ends in a blind pouch, and the lower section ascends from the stomach and connects with the trachea by a short fistulous tract.  A newborn with tracheoesophageal fistula with esophageal atresia appears to swallow normally, but soon after swallowing coughs, struggles, becomes cyanotic (skin turns blue in color), and stops breathing since he is inhaling aspirating) fluid returning from the blind pouch of the esophagus through his nose and mouth.  In this infant stomach distention may cause respiratory distress.  Also air and gastric contents (bile and gastric acid secretions) may reflux through the fistula into the trachea, resulting in chemical pneumonitis*.