An asymptomatic presentation of gastric outlet obstruction secondary to congenital antral web in an extremely preterm infant
- 1Imperial College Healthcare NHS Trust, Division of Neonatology, Winnicott Baby Unit, St Mary’s Hospital, London W2 1NY, UK
- 2New York Medical College, Department of Paediatrics, Maria Fareri Children’s Hospital, Westchester Medical Center, Valhalla, New York, NY 10595, USA
- 3Hospital for Sick Children, Paediatric Surgery, 1526, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
- 4Mount Sinai Hospital, Department of Paediatrics, 775A, 600 University Avenue, Toronto, Ontario, M5G 1X8, Canada
- Sunit V Godambe,
- Published 14 December 2009
A case of gastric outlet obstruction secondary to antral web in a preterm infant born at 25 weeks gestation is reported. The diagnosis was suspected on plain abdominal radiograph performed postnatally to confirm position of the umbilical catheters. On the initial radiograph (at age 1 h), a dilated stomach with a gasless abdomen was noted. A repeat chest and abdominal radiograph performed 24 h later due to increased ventilatory requirements showed persistence of this finding and upper gastrointestinal obstruction was suspected. An upper gastrointestinal contrast study confirmed the diagnosis of gastric outlet obstruction. The infant underwent a curative pyloroplasty on day 11 of life. The postoperative course was uneventful.
Congenital antral web is a rare cause of prepyloric gastric outlet obstruction with an incidence of approximately one in 100 000 births.1 Touroff and his colleagues were the first to report successful surgical correction of congenital prepyloric membranous obstruction in a premature infant in 1949.2 A review of the literature since then identified reports on five additional cases of gastric outlet obstruction due to antral web in preterm neonates.3–5 All of these cases were associated with epidermolysis bullosa (EB). Of the reported cases so far in the literature, the youngest gestational age at diagnosis was 29 weeks (twins who presented with EB and gastric outlet obstruction).3
In this report we present a case of gastric outlet obstruction secondary to antral web in an infant born at 25 weeks gestation. This case represents not only the youngest gestational age at which gastric outlet obstruction occurred, but also the earliest age at which the diagnosis was made in an asymptomatic infant. In addition, our case did not have associated EB as reported in all other cases.
This case report had approval from the Research Ethics Board of the Hospital for Sick Children, Toronto, Canada.
A 25 weeks gestational age preterm male infant was born to a 38-year-old G2P1 Caucasian mother. The pregnancy had been uncomplicated until 5 days before delivery, when she was hospitalised with vaginal bleeding and preterm labour. She received a course of antenatal corticosteroids and was subsequently discharged two days later as the contractions resolved. She was readmitted within 48 h in active labour and delivered. All antenatal ultrasound scans were normal with no evidence of polyhydramnios or distended stomach. At birth, the infant was age appropriate (birth weight 960 g, head circumference 25.5 cm, and length 36 cm (all above the 50th centile)). There was no evidence of dysmorphic features and systemic examination was normal. He was ventilated for respiratory distress syndrome and responded well to surfactant. The plain radiograph at 1 h of age to check the position of the umbilical catheters showed a distended stomach with air and no gas in the rest of the bowel. The gastric distension on the initial radiograph was attributed to the provision of bag and mask ventilation during resuscitation. He passed a small amount of meconium in the first 24 h of life and was started on trophic feeds on day 1 of life. A repeat chest and abdominal radiograph at 24 h later showed persistence of the dilated stomach with the same gasless abdomen (fig 1). Diagnosis of gastric outlet obstruction was suspected and confirmed with an upper gastrointestinal series.
The infant underwent pyloroplasty on day 11 of life. The obstruction was visualised at the level of the gastric antrum secondary to antral web at surgery. A pyloric transverse incision was made in case a pyloric atresia was found, thus requiring a pyloroplasty. The pyloroplasty was closed in a Finney fashion using 4.0 silk sutures.
Outcome and follow-up
The postoperative course was uneventful. The infant remained in the neonatal intensive care unit for a further 9 weeks for management of his prematurity, and was then discharged home.
Congenital gastric outlet obstruction secondary to antral web or diaphragm represents only about 1% of all gastrointestinal tract obstructions.5 Antral webs are thin, soft and pliable membranes composed of mucosa and submucosa of sufficient strength to resist manual dilatation, with a 2–3 mm orifice and located 1–3 cm proximal to the pyloroduodenal junction.6 The aetiology of antral webs is unknown. The webs probably represent the developmental products of excess local endodermal proliferation and redundancy.6 There is a slight male predominance reported in the literature.6 Associations with pyloric stenosis, EB, and cardiac conditions (coarctation of the aorta, ventricular septal defect, and patent ductus arteriosus) have been described in 28% of cases of antral web.6 Fifty per cent of cases with completely obstructed antral webs have normal antenatal ultrasound.6 Non-bilious vomiting with or without an upper abdominal quadrant mass are the most common presenting features in the neonatal period.3,5 Our patient is unique as he is the youngest age at which the diagnosis was made in an asymptomatic infant without evidence of polyhydramnios antenatally.
The suspicion of antral web usually occurs when the diagnosis of pyloric obstruction is made by a plain radiograph which reveals a large distended stomach with no air distal to it.7 Upper gastrointestinal radiographic studies may be helpful and in fact several investigators claim that these studies are 90% accurate in the diagnosis of a gastric outlet obstruction, possibly an antral web.7 Recently, ultrasound has been shown to identify antral web when performed by a skilled operator and is advantageous due to the non-invasive nature of the study.8 In our case the diagnosis was suspected on a plain film and contrast studies, although the definitive diagnosis was not made until the pylorus was opened.
Treatment alternatives of congenital antral webs are either surgical or conservative. The most common surgical procedure is pyloroplasty, with incision or excision of the membrane.7 As pyloric atresia cannot be ruled out on radiological investigation, a more definitive approach of a pyloric transverse incision is usually made. Other surgical options to dilate the thin membranous web are interventional radiology, endoscopy or gastrotomy. It must be remembered that the stomach in an infant of this size is as big as a large marshmallow! Non-obstructive webs found incidentally, or presenting with mild symptoms, can be treated conservatively with small thickened feeds and antispasmodics.7 Isolated cases of antral webs do well postoperatively like our patient; however, when associated with EB, the mortality is high.3,5
In conclusion, we underscore the fact that although gastric outlet obstruction is extremely rare in preterm infants, it should be suspected in asymptomatic infants with persistent gastric bubble and gasless abdomen on serial radiographs.
Gastric outlet obstruction is extremely rare in preterm infants and could be associated with polyhydramnios.
Gastric outlet obstruction should be suspected in an asymptomatic infant with persistent gastric distension and no gas in the rest of the abdomen on serial radiographs.
Upper gastrointestinal radiographic studies are 90% accurate in the diagnosis of gastric outlet obstruction, although ultrasound examination performed by a skilled operator may also be useful.
Treatment of congenital antral web is usually surgical, but cases of non-obstructive webs with mild symptoms can be treated conservatively with small thickened feeds and antispasmodics.
The mortality is high when associated with epidermiolysis bullosa.
Competing interests: none.
Patient consent: Patient/guardian consent was obtained for publication