Fig. 7.1
Esophageal stenosis: esophageal opacification showing a stenosis (arrowhead) in the middle portion of the esophagus
Clinically, a congenital stenosis may go unrecognized up to the introduction of solid type food; dysphagia, vomiting, and regurgitation may be the main symptoms [2]. It may also be discovered during the post-operative opacification of an esophageal atresia.
Upper GI tract opacification is the diagnostic procedure of choice as it will demonstrate the narrowing in the upper or middle esophagus in case of muscular thickening or diaphragm (Fig. 7.1); in the inferior part in case of tracheobronchial remnant. The most frequent localization of esophageal stenosis is the lower esophagus.
The initial treatment will be endoscopic dilatation followed by surgery in case of failure.
7.3.1.2 Esophageal Bronchus
Esophageal bronchus is a rare anomaly. It is characterized by a lobar bronchus branching from the esophagus. It may be associated with an esophageal atresia, a cardiovascular malformation or be part of a VACTERL syndrome. This malformation will rarely be diagnosed in utero [4]. It will be suspected postnatally, in case of a persistent basal atelectasis on a chest X-ray associated with recurrent infection and repeated coughing during feeding. Cautious esophageal opacification may visualize the bronchus within the atelectatic lung (Fig. 7.2). The (partially) aerated bronchus may be visualized on a chest CT usually performed during the workup of cardiovascular malformation or recurrent pulmonary infections [5].
Fig. 7.2
Esophageal bronchus: esophageal opacification showing lobar bronchus opacification branching from the esophagus (arrowhead)
7.4 Esogastric Anomalies: Congenital Hiatal Hernia
Hiatal hernia corresponds to the presence of the esogastric junction and of the stomach (partially or completely) within the chest. There are three types of hernia [6]: paraesophageal, sliding hernia, and hernia associated with congenitally short esophagus. This last type is the true congenital hiatal hernia and prenatal diagnosis is usually possible. It is a differential diagnosis of diaphragmatic hernia. When unrecognized in utero, symptoms, both digestive and respiratory, may develop rapidly after birth especially when the distended stomach remains in the chest. Symptoms may become even more acute when axial volvulus of the stomach occurs leading to gastric outlet obstruction. Noteworthy, hiatal hernia may be associated with intestinal malrotation.
On chest X-ray, the normally aerated pouch of the stomach will not be visible within the abdomen, conversely a distended air-filled structure will be seen above the diaphragm. An upper GI tract opacification will demonstrate the intrathoracic stomach and eventually the volvulus [6] (Fig. 7.3).
Fig. 7.3
Congenital hiatal hernia: Upper gastrointestinal tract opacification showing the intrathoracic position of the stomach
The treatment is surgical.
7.5 Gastroduodenal Anomalies
7.5.1 Congenital Microgastria
Congenital microgastria is rare [7]. It is characterized by a very small stomach; its extreme form is total agastria. It can be part of heterotaxia syndromes, Di George syndrome or VACTERL syndrome and long gap esophageal atresia. It should be suspected in case of intractable esophageal reflux and vomiting.
Microgastria will be ascertained through upper GI tract opacification by the demonstration of a small stomach (less than 25% of a normal stomach) lacking peristalsis with massive esophageal reflux with a distended esophagus [7] (Fig. 7.4).
Fig. 7.4
Congenital microgastria: Frontal view of an upper gastrointestinal tract opacification with a nasogastric tube demonstrates a small stomach and a distended duodenum
7.5.2 Early Onset Pyloric Stenosis
Early onset hypertrophic pyloric stenosis has been reported in the neonatal period [8–9] and even suspected in utero. Vomiting would be the main diagnostic feature.
On US, the pylorus appears long (>15 mm) with a muscular layer measuring >4 mm. No passage of liquid will be visualized through the hypertrophied pylorus. A cockade image will be visible on the transverse scan.
7.5.3 Duodenal Stenosis and Duodenal Web
Neonatal duodenal obstructions encompass a wide spectrum of anomalies related to intrinsic (e.g., duodenal atresia) and extrinsic (Ladd bands) causes [10]. Duodenal atresia is amenable to (an easy) antenatal diagnosis; if not, neonatal diagnosis will be rapid due to neonatal vomiting and confirmation by a plain film of the abdomen that will display the characteristic of double bubble [10]. The diagnosis of duodenal stenosis or web may be more challenging and delayed depending on the clinical symptoms. When suspected, plain film of the abdomen will demonstrate a distended stomach and proximal duodenum but with aeration of the downhill bowel; the partial obstruction/stenosis will be confirmed by upper GI opacification (Fig. 7.5) [10]. Rarely the web will be imaged by US [11]. Duodenal obstruction as in atresia, or sub-obstruction as in stenosis and web are classical findings of trisomy 21.
Fig. 7.5
Duodenal stenosis: Upper gastrointestinal tract opacification showing dilated proximal duodenal (arrowheads) with partial progression into the distal duodenum (arrow)
7.5.4 Duodenal Duplication Cyst
A duodenal duplication cyst is a common cause of bilious vomiting in the neonate. A cystic mass with a stratified wall will be visualized on US. An internal extrinsic compression of the duodenal bulb will be demonstrated on upper GI opacification [10].
7.6 Duodeno-Jejunal Obstructions: Midgut Volvulus and Ladd’s Band Related Obstruction
Midgut volvulus and obstruction secondary to Ladd’s band are both related to some degree of incomplete rotation. They determine acute symptoms and constitute surgical emergencies. Few cases will be discovered in utero [12] through obstetrical US but most will become symptomatic during the first days of life.
Color Doppler US should be performed very rapidly in order to search for the whirlpool sign so characteristic of midgut volvulus (Fig. 7.6) [11–13]. US may also demonstrate distended bowel loops and peritoneal effusion confirming intestinal obstruction. In doubtful cases, an upper GI tract opacification can be performed cautiously in order to verify the position of the duodeno-jejunal junction (Fig. 7.7).
Fig. 7.6
Midgut volvulus: (a) Transverse US scan of the epigastric area showing the displaced mesenteric vein (arrowhead). (b) Showing a typical color Doppler whirlpool sign
Fig. 7.7
Midgut volvulus: Upper gastrointestinal tract opacification showing the abnormal position of the duodeno-jejunal junction (Note the dilated loops behind indicating intestinal obstruction)
7.7 Mid and Lower GI Tract (Sub)Obstructions
In the neonatal period, distal intestinal obstruction will determine abdominal distension and delayed passage of meconium. The role of imaging will be to differentiate between small and large bowel obstructions. This will be achieved mainly on the basis of the size of the colon and the presence or absence of retrograde filling of the terminal ileal loops.
7.7.1 Jejunal and Ileal Atresia
Jejunal and ileal atresia are potentially diagnosed in utero [14]. Cases undiagnosed will become rapidly evident after birth due to abdominal distension and will necessitate rapid surgical management (Fig. 7.8).
Fig. 7.8
Intestinal atresia: radiopaque enema showing a micro-colon with passage of the ileocecal junction (arrowhead). Some distal ileal loops are opacified (arrow); the rest of the loops appear distended (curve arrow)
7.7.2 Meconium Related Anomalies
Meconium related anomalies include diseases acquired in utero or developing after birth only.
7.7.2.1 Meconium Ileus
Meconium ileus corresponds to accumulation of thick meconium in the terminal ileum determining uphill dilatation. The condition is mainly diagnosed in utero through the demonstration of dilated digestive tract (see Chap. 5). The condition is often associated with cystic fibrosis. After birth, there will be no passage of meconium and progressive abdominal distension. Radio-opaque enema with hydrosoluble contrast will demonstrate an unused microcolon and usually no passage through the terminal ileum (Fig. 7.9) [13]. If no passage is obtained, the treatment will be surgical.
