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386 Intestinal Atresia and Stenosis
History
Clinical Presentation
Intestinal atresias in Africa are usually not diagnosed prenatally.
However, atresias of the proximal jejunum are frequently associated
with polyhydramnios. Therefore, many of these patients are born pre-
maturely and often are small for their gestational age, the latter due to
inability to absorb nutrients from the amniotic fluid in patients with
proximal intestinal obstructions. 7
Intestinal atresia should be suspected in any newborn showing
evidence of bowel obstruction (bilious vomiting, abdominal distention,
and failure to pass meconium). Aspiration of >25 ml of fluid from the
stomach via a nasogastric tube (NGT) is very suggestive of obstruction.
Antenatal ultrasound scanning may show dilated loops of bowel with
vigorous peristalsis, which is diagnostic of obstruction. Polyhydramnios
may develop but it is more commonly seen in duodenal and oesophageal
obstructions. The more distal the atresia, the more generalized the
abdominal distention. After aspiration of gastric contents, the abdomen
will be less distended and visible peristalsis may be observed. There is
usually a failure to pass meconium, and typically small-volume gray
mucoid stools are passed. Abdominal tenderness or peritonitis develops
only with complications of ischaemia or perforation. This commonly
occurs with a delay in diagnosis and is due to increased intraluminal
pressure from swallowed air and secondary volvulus of the bulbous Figure 63.2: Abdominal radiograph showing several dilated gas-filled bowel
blind-ending bowel at the level of the first obstruction. loops in a jejunal atresia.
Physical Examination
Findings on physical examination are frequently not very revealing.
Most patients will have some degree of abdominal distention. The
amount of distention will vary, depending upon the level of obstruction.
Patients generally do not have abdominal tenderness or an abdominal
mass. Therefore, the presence of these findings suggests a complicated
obstruction associated with ischaemia or prenatal perforation, or that
the cause of obstruction may be malrotation with midgut volvulus.
Investigations
In most patients, a simple abdominal x-ray with anteroposterior (AP)
and either cross-table or left lateral decubitus projection are adequate to
make the diagnosis based upon the presence of dilated, air-filled intesti-
nal loops and air-fluid levels (Figure 63.2). In addition, plain abdominal
x-rays will suggest the level of obstruction based upon the number of
dilated bowel loops. The presence of multiple dilated bowel loops with-
out air-fluid levels suggests the possibility of meconium ileus, particu-
larly if the intestinal content has a “ground glass” appearance. A single
very dilated loop with a large fluid level is often indicative of atresia.
The differential diagnosis includes other causes of intestinal
obstruction in the neonate. In patients with evidence of a proximal
complete obstruction, the differential diagnosis is limited and no
additional diagnostic studies are required. In patients with multiple
dilated bowel loops, suggesting a distal obstruction, the differential
diagnosis includes several conditions for which surgical intervention
may not be required. Therefore, in these patients a contrast enema
may be helpful to look for evidence of a meconium plug or meconium
ileus, which may respond to nonoperative management. In addition, a Figure 63.3: Contrast enema showing normal colon with dilated proximal small
contrast enema may demonstrate findings suggestive of Hirschsprung’s bowel in an infant with jejunal atresia.
disease, which would direct initial management towards obtaining
confirmatory tests for this disease. A contrast enema showing a patent Management
colon is helpful in that demonstration of colonic patency by injection All patients should receive judicious fluid hydration prior to operative
of saline at operation—a sometimes tedious procedure—is not required intervention. In addition, a nasogastric or orogastric tube should be
(Figure 63.3). passed to empty the stomach and decrease the risk of vomiting with
In patients with intestinal stenoses, plain abdominal x-rays may aspiration. In general, patients with intestinal atresias have a low risk
demonstrate proximal bowel dilatation; however, in most patients a of associated cardiac anomalies, so that preoperative special investiga-
gastrointestinal contrast meal or enema is required to confirm and tion is not required unless the patient has clinical evidence of a serious
locate the site of partial obstruction. cardiac defect.