Esophageal Atresia

The esophagus can be obstructed in the form of esophageal atresia (EA), which is caused by a failure of separation of the esophagus from the trachea during normal development. Pure EA is rare and often coexists with tracheoesophageal fistula (TEF). A standard classification scheme describes the relationship between the atresia and the coexistent TEF (Figure 103-1). The most common combination is EA with distal TEF (type C). The most difficult to recognize and diagnose is “H-type,” which refers to isolated TEF without EA.

Figure 103-1 Tracheoesophageal fistula.

EA presents early in the newborn period with intolerance of feeds. Infants with EA have copious oral secretions that are difficult to control. They display nonbilious vomiting after the first feed and do not tolerate any additional feeds. Whether or not the abdomen is distended depends on the presence of TEF. If there is no connection between the trachea and distal portion of the esophagus, the abdomen will be gasless; if there is a distal connection, the stomach and abdomen will be distended. Infants with H-type EA or TEF tolerate feeds without difficulty and instead present with more subtle signs of tachypnea or recurrent pneumonia from pulmonary aspiration of feeds.

Pyloric Stenosis

Obstruction at the level of the pylorus from congenital abnormalities, such as webs or membranes, is rare in the immediate neonatal period. However, approximately one in 500 infants will develop hypertrophic pyloric stenosis (HPS) during the first month of life (Figure 103-2). The classic presentation of HPS is a 3- to 4-week-old infant with persistent nonbilious projectile vomiting after each feed. Although found in male and female infants of all ethnicities, first-born male white infants seem to be disproportionately affected. Use of the antibiotic erythromycin in the neonatal period is a known risk factor as well. Infants with HPS appear irritable and hungry, and in some cases, a mass in the shape of an olive can be palpated in the right upper quadrant, representing the hypertrophic pyloric sphincter. Immediately after feeding, a reverse peristaltic wave may be seen just before vomiting. The abdomen may appear scaphoid before air and feeds are not able to pass beyond the level of the pylorus.

Figure 103-2 Hypertrophic pyloric stenosis.

Intestinal Atresias and Stenosis

Intestinal atresias are possible at any point along the GI tract. Jejunoileal atresia is the most common atresia followed by duodenal atresia and finally colonic atresia. Presenting signs and symptoms are nonspecific and similar to those of other obstruction syndromes. Duodenal and jejunal atresias generally present with bilious emesis. More distal obstruction often still have emesis but may present with more subtle signs of feeding intolerance, including abdominal distension. In addition, the time to onset of symptoms and the presence of maternal polyhydramnios can suggest the location of stenosis. More distal obstructions take longer to present, and it is less likely that the mother will have had polyhydramnios because amniotic fluid is absorbed in the proximal small bowel.

Malrotation and Volvulus

Malrotation refers to a disruption of the normal rotational process of the midgut, resulting in abnormal fixation of the duodenum. This creates a stalk around which the gut can twist intermittently, creating bowel obstruction and ischemia. The peak time of presentation is within the first month of life, and there is a 2 : 1 male predominance. Symptoms at the time of presentation are as highlighted above for obstruction syndromes, but bilious emesis in a neonate should prompt immediate concern for volvulus. Malrotation without volvulus can manifest simply as reflux or feeding intolerance.

Hirschsprung’s Disease

Hirschsprung’s disease results from failure of the ganglion cells to develop in the myenteric plexus of the colon, resulting in dysfunctional peristalsis. There is a wide range of severity, and infants with severe cases may present with the signs of obstruction outlined above. Mildly affected infants often have a delayed presentation characterized by failure to pass meconium within the first 24 hours of life or intractable constipation. On examination, the abdomen is often distended but is generally not tender.

Meconium Ileus, Meconium Plug Syndrome, and Small Left Colon Syndrome

Meconium ileus refers to impaction of the distal ileum by inspissated meconium from birth. The specific terminology of meconium ileus refers to impaction that occurs in a patient with cystic fibrosis (CF). This results from high viscosity of meconium in CF patients because of a lack of pancreatic enzyme activity along with abnormal mucous secretion. Meconium plug syndrome and small left colon syndrome both appear to be related to poor gut motility rather than intrinsic obstruction, and both are seen most often in the setting of infants of diabetic mothers. Presenting signs and symptoms in all cases include abdominal distension shortly after birth. This may be followed by emesis and intolerance of feeds.

Imperforate Anus

Imperforate anus results from a failure of the normal development of the hindgut. The presence of imperforate anus should be apparent on physical examination and may be associated with other congenital anomalies (i.e., VACTERL [vertebral anomalies, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, renal or radial anomalies, and limb defects] association; see Chapter 120).

Esophageal Atresia

In cases of suspected EA, initial abdominal radiographs may reveal a gasless abdomen. Placement of a NG or OG tube may be met with resistance. Injection of air through the NG tube can be used as contrast before chest radiographs are performed, thereby highlighting a blind-ended esophageal pouch. In cases of suspected H-type TEF, a dedicated upper GI radiography series may be required to confirm diagnosis. After diagnosis is confirmed, surgical repair via thoracotomy and reanastomosis of the esophagus is required. In the presence of a TEF, the fistula should be repaired early in the hospital course to prevent ongoing soiling of the lungs. In cases with other associated anomalies, surgical repair may be delayed or performed in several stages to allow for adequate growth.

Pyloric Stenosis

Initial stabilization of infants suspected of having HPS should include hydration with IV fluids, determination of electrolytes, and imaging. Hypochloremic hypokalemic metabolic alkalosis is the electrolyte abnormality associated with HPS. Abdominal ultrasound is the definitive diagnostic test for HPS, and criteria for the diagnosis of HPS are a pyloric canal longer than 1.4 cm in length or a thickness of 0.3 cm or greater. Definitive management requires surgical pyloromyotomy.

Intestinal Atresias

The initial workup for intestinal atresia should proceed as highlighted above. In addition to abdominal plain radiography, contrast studies including upper GI studies with follow-through may be needed to identify the level of intestinal obstruction before surgical repair.

Malrotation and Volvulus

When an infant presents with bilious emesis, an upper GI series must be performed emergently because the time from presentation to operation will determine the amount of viable intestine saved when there is a volvulus. Malrotation is diagnosed when the upper GI series demonstrates an abnormal point of attachment of the ligament of Treitz. Surgical management with a Ladd’s procedure is required to release the mesentery. This topic is covered in greater detail in Chapter 109.

Hirschsprung’s Disease

Abdominal plain radiographs may reveal dilated bowel loops or the presence of stool in the colon, and a barium enema may show a transition point in affected patients (Figure 103-3). Definitive diagnosis is made with a suction rectal biopsy to evaluate for the presence of ganglion cells. Surgical repair is required to remove the aganglionic section of bowel and restore normal peristalsis.

Figure 103-3 Hirschsprung’s disease.

Meconium Ileus, Meconium Plug Syndrome, and Small Left Colon Syndrome

These entities have similar diagnostic workup that includes abdominal radiography. Key findings include intestinal distension proximal to the site of obstruction and possibly calcifications within the meconium. Barium enema may be used to better identify the point of obstruction, and it may also be therapeutic in the setting of meconium plug syndrome. In meconium ileus, contrast enema will demonstrate a small, unused colon and meconium pellets in the distal ileum. Because of the specificity of this disease for CF, genetic testing should be undertaken (see Chapter 41). If water-soluble enema fails to relieve the obstruction or if the obstruction is complicated by proximal volvulus, surgical intervention is indicated.

Imperforate Anus

Surgical reconstruction is necessary for patients with imperforate anus. Often a perianal fistula will allow for a contrast enema that may clarify the severity of the imperforate anus. The distance from the end of the large intestine to the perineum will dictate the complexity of surgical repair. A diverting colostomy may be required to allow the patient to grow before definitive repair.