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Esophageal, gastric, duodenal, and sometimes jejunal obstruction should be considered when excess amniotic fluid (polyhydramnios) is diagnosed, because such obstructions prevent the fetus from swallowing and absorbing amniotic fluid (jejunal obstruction—see Congenital Gastrointestinal Anomalies: Jejunoileal and Large-Bowel Obstruction). An NGT should be passed into the neonate's stomach immediately after delivery. Finding large amounts of fluid in the stomach, especially if bile-stained, supports the diagnosis of upper GI obstruction, whereas inability to pass the NGT into the stomach suggests esophageal atresia (or nasal obstruction [eg, choanal atresia]). Diaphragmatic hernia sometimes causes high alimentary tract obstruction.
Esophageal Atresia
Esophageal atresia is incomplete formation of the esophagus, frequently associated with tracheoesophageal fistula. Diagnosis is suspected by failure to pass an NGT. Treatment is surgical repair.
Esophageal atresia is the most common GI atresia. The estimated incidence is 1 in 3000 live births. Other congenital malformations are present in up to 50% of cases.
There are 5 major types of esophageal atresia (see Fig. 1: Congenital Gastrointestinal Anomalies: Types and relative frequencies of esophageal atresia and tracheoesophageal fistula. ). Most also involve a fistula between the trachea and esophagus.
Characteristic signs are excessive secretions, coughing and cyanosis after attempts at feeding, and aspiration pneumonia. Esophageal atresia with a distal fistula leads to abdominal distention because, as the infant cries, air from the trachea is forced through the fistula into the lower esophagus and stomach.
Diagnosis
Routine prenatal ultrasonography may suggest esophageal atresia. Polyhydramnios may be present but is not diagnostic because it can occur with many other disorders. The fetal stomach bubble may be absent but only in < 50% of cases. Less commonly, there is a dilated upper esophageal pouch, but this is typically looked for only in fetuses with polyhydramnios and no stomach bubble.
After delivery, an NGT is inserted if esophageal atresia is suspected by prenatal ultrasonography or clinical findings; diagnosis is suggested by inability to pass the tube into the stomach. A radiopaque catheter determines the location of the atresia on x-ray. In atypical cases, a small amount of water-soluble contrast material may be needed to define the anatomy under fluoroscopy. The contrast material should be quickly aspirated back because it can cause a chemical pneumonitis if it enters the lungs. This procedure should be done only by an experienced radiologist at the center where neonatal surgery will be done.
Treatment
Preoperative management aims to get the infant into optimal condition for surgery and prevent aspiration pneumonia, which makes surgical correction more hazardous. Oral feedings are withheld. Continuous suction with a double-lumen catheter in the upper esophageal pouch prevents aspiration of swallowed saliva. The infant should be positioned prone with the head elevated 30 to 40° and with the right side down to facilitate gastric emptying and minimize the risk of aspirating gastric acid through the fistula. If definitive repair must be deferred because of extreme prematurity, aspiration pneumonia, or other congenital malformations, gastrostomy is done to decompress the stomach. Suction through the gastrostomy tube then reduces the risk that gastric contents will reflux through the fistula into the tracheobronchial tree.
When the infant's condition is stable, extrapleural surgical repair of the esophageal atresia and closure of the tracheoesophageal fistula can be done. Occasionally, interposing a segment of colon between the esophageal segments may be required.
The most common acute complications are leakage at the anastomosis site and stricture formation. Feeding difficulties are common after successful surgical repair because of poor motility of the distal esophageal segment, which occurs in up to 85% of cases. This poor motility predisposes the infant to gastroesophageal reflux. If medical management for reflux fails, a Nissen fundoplication may be required.
Diaphragmatic Hernia
Diaphragmatic hernia is protrusion of abdominal contents into the thorax through a defect in the diaphragm. Lung compression may cause persistent pulmonary hypertension. Diagnosis is by chest x-ray. Treatment is surgical repair.
Diaphragmatic hernia usually occurs in the posterolateral portion of the diaphragm (Bochdalek's hernia) and is on the left side in 90% of cases. The estimated incidence is 1 in 2200 live births. Anterior hernias (Morgagni's hernia) are far less common. Other congenital anomalies are present in about 50% of cases.
Loops of small and large bowel, stomach, liver, and spleen may protrude into the hemithorax on the involved side. If the hernia is large, the lung on the affected side is hypoplastic. Other pulmonary consequences include underdevelopment of the pulmonary vasculature, resulting in an elevation of pulmonary vascular resistance and hence pulmonary hypertension. Persistent pulmonary hypertension (see Respiratory Disorders in Neonates, Infants, and Young Children: Persistent Pulmonary Hypertension of the Newborn) leads to right-to-left shunting at the level of the foramen ovale or through a patent ductus arteriosus, which prevents adequate oxygenation even with O2 supplementation or mechanical ventilation. Persistent pulmonary hypertension is the major cause of death among infants with congenital diaphragmatic hernia.
Symptoms and Signs
After delivery, as the neonate cries and swallows air, the loops of intestine quickly fill with air and rapidly enlarge, causing further acute respiratory embarrassment as the heart and mediastinal structures are pushed to the right, compressing the more normal right lung. Respiratory distress is immediate in severe cases. A scaphoid abdomen (due to displacement of abdominal viscera into the chest) is likely. Bowel sounds (and an absence of breath sounds) may be heard over the involved hemithorax. In less severe cases, mild respiratory difficulty develops a few hours or days later as abdominal contents progressively herniate through a smaller diaphragmatic defect.
Diagnosis
Sometimes diagnosis is by prenatal ultrasonography. After delivery, diagnosis is by chest x-ray showing intestine protruding into the chest. In a large defect, there are numerous air-filled loops of intestine filling the hemithorax and contralateral displacement of the heart and mediastinal structures. If the x-ray is taken immediately after delivery before the neonate has swallowed air, the abdominal contents appear as an opaque airless mass in the hemithorax.
Treatment
The neonate should be immediately endotracheally intubated and ventilated in the delivery room; bag-and-mask ventilation may fill the intrathoracic viscera with air and worsen respiratory compromise. Continuous nasogastric suction with a double-lumen tube prevents swallowed air from progressing through the GI tract and causing further lung compression. Sometimes paralytic drugs are needed to prevent swallowing of air. Surgery is required to replace the intestine in the abdomen and to close the diaphragmatic defect after the neonate has had optimal management of pulmonary hypertension.
Severe persistent pulmonary hypertension requires stabilization before surgery with IV NaHCO3 and inhaled nitric oxide, which may help dilate the pulmonary arteries and improve systemic oxygenation. Recent studies show improved outcome with use of extracorporeal membrane oxygenation (ECMO); however, neonates with extreme pulmonary hypoplasia still do not survive. Successful transport of a critically ill neonate with congenital diaphragmatic hernia and persistent pulmonary hypertension is very difficult. Therefore, if diaphragmatic hernia is diagnosed by prenatal ultrasonography, delivery at a pediatric center with ECMO facilities is prudent.
Duodenal Obstruction
The duodenum can be obstructed by atresia, stenosis, and pressure due to an extrinsic mass.
Duodenal atresia
This anomaly is the 3rd most common atresia of the GI tract. The estimated incidence is 1 in 20,000 live births. Duodenal atresia is due to the failure of canalization of the embryonic duodenum. About 30% of infants with duodenal atresia have Down syndrome. Other congenital anomalies, particularly malrotation of the intestine, occur in 50 to 70% of cases.
Diagnosis can be suspected prenatally if there is polyhydramnios, dilated bowel, ascites, or a combination. Infants with duodenal atresia present with polyhydramnios, feeding difficulties, and emesis that may be bilious. The diagnosis is suspected by symptoms and classic double-bubble x-ray findings—one bubble is in the stomach and the other is in the proximal duodenum; little to no air is in the distal gut. An upper GI series provides definitive diagnosis but must be done carefully by a radiologist experienced with doing this procedure on children to avoid aspiration. Once the disorder is suspected, infants should receive nothing by mouth, and an NGT should be placed to decompress the stomach. Surgery is the definitive therapy.
Duodenal stenosis
This anomaly occurs less commonly than duodenal atresia but manifests in a similar fashion and requires surgery. It too is frequently associated with Down syndrome.
Choledochal cyst or annular pancreas
These anomalies may obstruct the duodenum by extrinsic pressure. Infants with choledochal cyst classically present with a triad of abdominal pain (a very difficult finding to infer in the neonate), right upper quadrant mass, and jaundice. If the cyst is large, it may also manifest with variable degrees of duodenal obstruction. Choledochal cyst is most commonly diagnosed by ultrasonography. Treatment is surgical and requires complete excision of the cyst because of the risk of developing cancer in the cyst remnants.
Annular pancreas is a rare congenital anomaly in which pancreatic tissue encircles the 2nd portion of the duodenum, causing duodenal obstruction; manifestation is usually during the neonatal period but may be delayed until adulthood. The diagnosis can be suggested by an upper GI series and is more definitively made with CT. Treatment is surgical.
Last full review/revision September 2009 by William J. Cochran, MD
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