CONGENITAL GASTRIC OUTLET OBSTRUCTION

ETIOLOGY

• Pyloric atresia (incomplete recanalization of the foregut or an intrauterine vascular accident. It's familial occurrence suggests that it may be inherited as an autosomal recessive condition (1).
  It has also been described in association with epidermolysis bullosa (damaged luminal mucosa is replaced by scar tissue that causes pyloric stenosis (1,2).
• Membranous antral web.

PATHOPHYSIOLOGICAL CLASSIFICATION (3)

1. Antral gap atresia.
2. Pyloric gap atresia (types I-III).
3. Pyloric septum (solid atresia).
4. Pyloric membrane (types I-II).
5. Antral membrane (web and "windsock type").

ULTRASOUND

• Prenatal diagnosis is infrequently made due to variations in the normal gastric dimensions (Normograms have been reported).
• Gastric dilatation.
• Polyhydramnios (usually in the third trimester) (5).
• Dilated esophagus ± gastroesophageal reflux.
• High incidence of extraintestinal anomalies (28%) (6).
• No association with fetal aneuploidy.

REFERENCES

1. Adashi EY, Louis FJ, Vasque M. An unusual case of epidermolysis bullosa hereditaria letalis with cutaneous scarring and pyloric atresia. J Pediatr 1980;96:443.
2. Orense M, Garcia-Hernandez JB, Celorio C et.al. Pyloric atresia associated with epidermolysis bullosa. Pediatr Radiol 1987;17:435.
3. Moore CCM. Congenital gastric outlet obstruction. J Pediatr Surg 1989;24:1241-1246.
4. Weissman A, Achiron R, Kuint J et.al. Prenatal diagnosis of congenital gastric outlet obstruction. Prenat Diagn 1994;14:888-891.
5. Barkin SZ, Pretorius DH, Beckett MK et.al. Severe polyhydramnios: Incidence of anomalies. AJR 1987;148:155.