Oesophageal abnormalities: Potentially lethal oesophageal abnormalities occur in 1 in 3000 live births and there is associated polyhydramnios in nearly 30%. Oesophageal atresia with a distal tracheo-oesophageal fistula (TOF, Fig. 50.3) accounts for 90% of these, pure oesophageal atresia without a fistula for 5% and other variations for the other 5%. Babies with oesophageal atresia may have other abnormalities as part of a spectrum of disorders, the VACTERL association. This may include one or more V—vertebral, A—anorectal, C—cardiac, T—TOF, E—‘(o)esophageal’ atresia, R—renal and L—limb abnormalities.

Oesophageal atresia may be suspected before birth if there is an absent gastric bubble on ultrasound scan together with polyhydramnios but these are unreliable signs. If a newborn infant has excessive frothy saliva around the mouth, this diagnosis must be excluded before feeding to prevent choking or cyanotic attacks with fluid entering the lungs by aspiration from the blind upper pouch or by regurgitation of acid from the stomach via the fistula. Aspiration pneumonia is a serious complication. The diagnosis of atresia is made by passing a nasogastric tube (10 F gauge) through the mouth. If gastric contents are not aspirated, a plain X-ray showing the tube lodged in the upper pouch confirms the diagnosis. If the oesophagus is obstructed but there is gas in the stomach, there must be a fistula between distal oesophagus and trachea.

Operation is performed soon after diagnosis and after excluding other abnormalities, particularly cardiac, which may interfere with anaesthesia or intrinsically have a very poor prognosis. Most are corrected by dividing the fistula and primary oesophageal anastomosis. Oral feeding can usually be started a few days after surgery.

Dysphagia commonly occurs following technically successful reconstruction, with boluses sometimes sticking and causing obstruction because the peristaltic wave is uncoordinated. It can be managed with a diet of finely chopped food until the child learns to chew food thoroughly, often after the age of 4 years. Anastomotic strictures can occur and need dilatation. Most patients after oesophageal atresia wean slowly, are slower eaters, and need to drink more during meals.

In pure oesophageal atresia without fistula there is usually a wide gap between upper and lower oesophagus. Reconstruction is by delayed primary anastomosis at 4–6 weeks or by using a gastric, colonic or small bowel conduit when the baby is bigger. Until then, feeding is via a gastrostomy. The upper end of the pouch is usually brought out as an oesophagostomy; the baby is given sham oral feeds when receiving gastrostomy feeds, so swallowing can be learnt.

Duodenal obstruction: Duodenal atresia causes obstruction of the second part of the duodenum, usually just below the common bile duct entry resulting in bile-stained vomiting. The anomaly is a web across the lumen or complete separation of the bowel ends. If the web is incomplete, there is initial poor feeding and failure to thrive until a milk curd impacts, causing obstruction. Plain abdominal X-ray shows a double bubble, with one air–fluid interface in the stomach and another in the duodenum (Fig. 50.1a).

Provided there is no malrotation or volvulus, surgery can be delayed. This involves joining proximal duodenum to duodenum distal to the obstruction as a duodeno-duodenostomy. The ends can easily be brought together without tension so bypass procedure is not necessary. Previously, gastrojejunostomy was performed but often led to bacterial colonisation of the defunctioned loop causing failure to thrive, stomal ulceration and gastrointestinal bleeding. Recovery after duodeno-duodenostomy is often slow because the proximal duodenum is atonic and peristalsis slow to start. Almost all patients need perioperative total parenteral nutrition.

Jejuno-ileal atresias: Jejunal or ileal atresias are similar to duodenal atresia, with a gap between bowel ends or an intraluminal web. A gap is often the result of a mesenteric vascular accident in utero. Obstructions occur at any level and are sometimes multiple. Bile-stained vomiting and abdominal distension are often associated with visible peristalsis and hypertrophied proximal bowel. The diagnosis is usually evident from the abdominal X-ray.

Obstruction may be present from birth or delayed a few days if a web is incomplete. Presenting signs depend on the level of obstruction: high jejunal obstruction presents like duodenal atresia or malrotation with bile-stained vomiting and a lack of gas on X-ray (Fig. 50.1a); low ileal obstruction presents like meconium ileus or Hirschsprung’s disease, with failure to pass meconium, poor feeding, abdominal distension and dilated intestine on X-ray. Small bowel atresia is sometimes associated with cystic fibrosis, and patients should have a genetic screen and a sweat test to exclude it.

Surgery involves resecting the web segment or the blind ends and end-to-end anastomosis. Return of intestinal function may be slow, but may be accelerated if the most dilated and atonic proximal bowel is resected too (Fig. 50.4).

Pathophysiology: The midgut develops outside the abdomen during early embryological development. By the end of the third month, it normally returns, rotating 270° anti-clockwise, giving a normally sited duodeno-jejunal (DJ) flexure and the caecum in the right iliac fossa. The midgut mesentery is wide, stretching obliquely across the posterior abdominal wall, preventing volvulus. If rotation is incomplete, the DJ flexure lies right of the midline rather than left; the mesenteric fixation to the posterior abdominal wall is narrow and volvulus may occur. At one time Ladd’s bands (peritoneal folds across the duodenum) were thought responsible but it is now known that volvulus is the usual cause.

Acute volvulus: