Congenital microgastria is a rare anomaly resulting from arrested embryogenesis of the dorsal mesogastrium in early fetal development. It is often associated with other intestinal malformations, as well as cardiac, renal, and skeletal anomalies. Affected infants have severe feeding difficulties and poor weight gain. While small, frequent enteric feeds have been successful in mild cases, most microgastria patients require operative intervention to increase the gastric reservoir.
PATHOGENESIS AND EPIDEMIOLOGY
Since it was first described in 1894, only 65 cases of microgastria have been described in world literature. The condition is the result of impairment in normal differentiation of the caudal part of the primitive gastric foregut. Specifically, it is characterized by failure of gastric rotation during weeks 4 to 8 of gestation and associated lack of differentiated gastric growth. The impairment results in a megaesophagus with a small tubular stomach that has a small functional capacity. Since the spleen and stomach are both derived from the embryonic dorsal mesogastrium, it is commonly associated with asplenia.
In most cases, microgastria presents beyond the neonatal period with recurrent postprandial vomiting, failure to thrive, and recurrent aspiration pneumonia, due to the weakened lower esophageal sphincter and associated megaesophagus. Diarrhea has also often been reported, which may result from small gastric capacity with rapid emptying of acid content. Consequently, patients often present with malnutrition, growth retardation, and developmental delay. Because the total cell mass of the stomach is severely reduced, patients are also at risk for pernicious anemia secondary to a deficiency in intrinsic factor. Isolated microgastria is uncommon, as it is often accompanied by the VACTERL (vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities) association, as well as asplenia, situs inversus, limb hypoplasia, intestinal malrotation, laryngotracheal clefts, and cardiac abnormalities.
Prenatal diagnosis of microgastria is suggested by failure of visualization of the fetal stomach on ultrasound early in the second trimester. However, the same findings can be seen in cases of esophageal atresia. Confirmatory postnatal diagnosis of congenital microgastria requires a contrast study of the upper gastrointestinal tract, demonstrating an abnormally small, tubular, or sacular stomach that lies in the midsaggital plane. The study would also often demonstrate associated incompetence of the lower esophageal sphincter and megaesophagus (Fig. 395-1). When identified, screening for associated anomalies is warranted.
Upper gastrointestinal radiograph showing the typical small-volume tubular stomach (arrow), incomplete rotation, and gastroesophageal reflux in a patient with microgastria.
The approach to management of microgastria is case specific and is related to the severity of symptoms. In mild cases, nonoperative management in the form of small, frequent enteric (either nasogastric or direct gastric) feeds ...