Duodenal Atresia

Question 1

What is duodenal atresia?

Answer 1

Duodenal atresia is a congenital obstruction of the duodenum due to an intrinsic structural abnormality in the intestinal wall, which may include conditions ranging from stenosis or a fenestrated web to a complete interruption of the lumen with two blind-ending pieces of bowel.

Question 2

What is meant by “intestinal atresia”?

Answer 2

Intestinal atresia refers to a congenital obstruction of the intestinal lumen, caused by a structural abnormality in the intestinal wall.

Question 3

What are the types of pathology associated with intestinal atresia?

Answer 3

The spectrum of pathology includes:
• Stenosis or fenestrated web
• A simple obstructing membrane across the lumen
• An interrupted lumen with two blind-ending pieces of bowel

Question 4

What happens to the duodenal lumen during embryonic development

Answer 4

Between the 5th and 8th weeks of embryonic life, the duodenal lumen passes through a solid phase.

Question 5

What could cause duodenal atresia during embryogenesis?

Answer 5

Disruption in the normal cannulation of the duodenal lumen due to an unknown embryological insult during the second month of pregnancy.

Question 6

Why is it suggested that duodenal atresia is due to an early insult during embryogenesis?

Answer 6

Because of the frequent coexistence of other anomalies, suggesting that the insult affects the embryo as a whole.

Question 7

What is the incidence of duodenal atresia?

Answer 7

The incidence is 1:3400 live births, and it occurs equally in males and females.

Question 8

What biliary abnormalities can be associated with duodenal atresia?

Answer 8

• Bifid pancreatic duct
• Annular pancreas (pancreatic tissue surrounding the second part of the duodenum)

Question 9

What is the association between duodenal atresia and Trisomy 21?

Answer 9

Duodenal atresia is highly associated with Trisomy 21 in approximately 30% of cases.

Question 10

What is duodenal stenosis and how does it differ from duodenal atresia?

Answer 10

• Duodenal stenosis is an incomplete obstruction of the duodenal lumen that may present at various ages and has clinical findings depending on the degree of stenosis.
• Duodenal atresia is the complete obliteration of the lumen.

Question 11

Where do most congenital duodenal obstructions occur?

Answer 11

Most congenital duodenal obstructions occur in the second part of the duodenum and are considered periampullary.

Question 12

How does the biliary outlet relate to the site of duodenal obstruction?

Answer 12

In most cases, the biliary outlet occurs either proximal or distal to the site of duodenal obstruction.

Question 13

What radiological feature is typical for congenital duodenal obstruction?

Answer 13

The typical radiological feature is a ‘double bubble’, caused by the dilation of the proximal duodenum and stomach.

Question 14

What is a common finding in the antenatal diagnosis of duodenal atresia?

Answer 14

Polyhydramnios is present in 40% of cases.

Question 15

What growth abnormality is often seen antenatally in duodenal atresia?

Answer 15

Growth retardation is commonly observed.

Question 16

What antenatal ultrasound findings are indicative of duodenal atresia?

Answer 16

Dilated stomach and dilated first part of the duodenum on ultrasound.

Question 17

What ultrasound features might suggest Trisomy 21 antenatally in duodenal atresia cases?

Answer 17

Ultrasound features of Trisomy 21 may be present in approximately 25% of cases.

Question 18

How does antenatal detection benefit the management of duodenal atresia?

Answer 18

Antenatal detection enables planned in-utero transfer and delivery at a tertiary unit with neonatal ICU and paediatric surgical expertise.

Question 19

What percentage of babies with duodenal atresia are born prematurely?

Answer 19

50% of babies with duodenal atresia are born prematurely.

Question 20

What is the typical vomiting pattern in duodenal atresia?

Answer 20

• Bile-stained vomitus within 24 hours of birth is typical, except in a few cases where the atresia is proximal to the ampulla of Vater.
• In cases of duodenal fenestrated web/stenosis, patients may present later with persistent milk vomiting, failure to thrive, or recurrent aspiration pneumonias.

Question 21

What physical sign is commonly observed in babies with duodenal atresia?

Answer 21

Epigastric distension is commonly seen.

Question 22

How does the passage of meconium differ in babies with duodenal atresia?

Answer 22

Babies with duodenal atresia may not pass any meconium or may only pass a small amount, which could be white meconium, unlike the typical black, sticky meconium passed within 24 hours by over 90% of newborns.

Question 23

What biochemical abnormalities are associated with duodenal atresia?

Answer 23

Due to ongoing vomiting of upper gastrointestinal contents, there is a hypochloraemic, hyponatraemic metabolic alkalosis.

Question 24

What percentage of infants with duodenal atresia develop jaundice?

Answer 24

Approximately 40% of infants with duodenal atresia develop jaundice, often due to disrupted enterohepatic circulation or sepsis.

Question 25

What is the first imaging study that should be performed in all cases of duodenal atresia?

Answer 25

An abdominal x-ray should be performed in all cases.

Question 26

How can the typical “double bubble” appearance be enhanced on an abdominal x-ray?

Answer 26

The typical ‘double bubble’ appearance can be enhanced by introducing air via a nasogastric tube.

Question 27

When is a contrast meal and follow-through essential in the diagnosis of duodenal atresia?

Answer 27

A contrast meal and follow-through are essential when distal gas is present, which may be due to a bifid pancreatic duct or fenestrated duodenal web. These conditions are rare, but midgut volvulus due to malrotation must be excluded as it requires more urgent surgical intervention.

Question 28

How can midgut volvulus be differentiated from duodenal atresia on imaging?

Answer 28

Midgut volvulus should be suspected if the proximal dilated bowel appears beaked rather than rounded on x-ray or contrast imaging.

Question 29

What is the association between duodenal atresia and Trisomy 21 (Down syndrome)?

Answer 29

30% of babies with duodenal atresia have Trisomy 21 (Down syndrome).

Question 30

What physical features should you look for to identify possible Trisomy 21 in a baby with duodenal atresia?

Answer 30

• Epicanthic folds • Widely spaced eyes • Poor tone • Single transverse (simian) palmar crease • Sandal gap between the 1st and 2nd toes • 3rd fontanelle • Cardiac murmur from a ventricular septal defect • Cardiac defects: ~20% • Associations with VACTERL and other anomalies are described

Question 32

What are the initial steps in preparing a baby with duodenal atresia for surgery?

Answer 32

• Nasogastric tube on free drainage • Nil by mouth • Intravenous fluids for resuscitation, maintenance, and fluid replacement • Broad spectrum intravenous antibiotics if septic or very distended • Maintain warmth • Monitor serum glucose levels

Question 33

What respiratory support might be needed for a baby with duodenal atresia?

Answer 33

Oxygen via nasal cannula or intubation if the baby is distressed.

Question 34

What should be closely monitored in a baby preparing for surgery?

Answer 34

Cardiovascular, respiratory, and metabolic status should be closely monitored.

Question 35

What is the most urgent differential diagnosis to consider in babies with duodenal atresia?

Answer 35

Midgut volvulus must be urgently excluded in babies with an x-ray picture of duodenal atresia (the ‘double bubble’), especially if distal bowel gas is visible via a contrast meal and duodenal c-loop follow-through.

Question 36

How can gastro-oesophageal reflux be distinguished from duodenal atresia?

Answer 36

Gastro-oesophageal reflux causes persistent milk vomiting that can turn bile-stained, but it rarely leads to biochemical abnormalities.

Question 37

What radiological findings differentiate jejuno-ileal atresias or other obstructions from duodenal atresia?

Answer 37

Jejuno-ileal atresias or other causes of obstruction would show a different radiological picture, but may also cause bile-stained vomiting and sepsis.

Question 38

When is surgery typically performed for duodenal atresia?

Answer 38

Surgery is usually performed on the 2nd or 3rd day postnatally once the baby is stable, which includes correcting dehydration, metabolic derangements, improving aspiration pneumonia, and adjusting to extra-uterine life (e.g., closure of patent ductus arteriosus and resolution of transient tachypnoea).

Question 39

When is immediate surgery necessary for a baby with duodenal atresia?

Answer 39

Immediate surgery is performed if midgut volvulus is suspected in cases of “double bubble” on abdominal x-ray, especially when the proximal atretic bowel shows beaking rather than the typical rounded distended bowel of duodenal atresia.

Question 40

What should be done if there is a delay before surgery for duodenal atresia?

Answer 40

Intravenous (parenteral) nutrition should be started, ideally via a central venous line or a peripherally inserted central catheter (PICC), if there is a delay before surgery.

Question 41

What is the typical approach for duodenoduodenostomy surgery?

Answer 41

The surgery is typically performed via a transverse laparotomy, though it may also be done laparoscopically in some institutions.

Question 42

How is the duodenal obstruction bypassed in duodenoduodenostomy surgery?

Answer 42

A bypass is performed rather than excision of the atretic ends to avoid injury to the nearby bile duct. A transverse incision on the proximal dilated atretic bowel is sutured to a longitudinal incision on the distal undilated bowel, creating a diamond-shaped anastomosis for wide drainage.

Question 43

What post-operative care is required in the early period after duodenoduodenostomy surgery?

Answer 43

• Analgesia and intensive care monitoring • Nasogastric drainage with replacement of gastrointestinal fluid losses >10ml/kg/day until losses decrease and become pale green/non-bilious. • Parenteral nutritional support may be required until 75% of nutritional needs are met orally.

Question 44

How should oral feeding be initiated post-operatively for duodenal atresia?

Answer 44

Early initiation of small volumes of oral breast milk helps stimulate the development of normal swallowing reflexes, gastrointestinal motility, and endothelin growth factors, promoting progression to full oral feeds.

Question 45

What is a common complication in the early post-operative period for duodenal atresia patients?

Answer 45

Intermittent vomiting is common due to poor motility of the proximal dilated bowel. Small, frequent feeds and a 30° head-up position help prevent vomiting and aspiration.

Question 46

What long-term concerns should be monitored for duodenal atresia patients post-surgery?

Answer 46

The proximal dilated bowel will always have increased calibre and impaired motility. Patients with a history of duodenal atresia who ingest foreign bodies are at an increased risk for foreign body obstruction and should be monitored, including with serial radiographs for swallowed objects.

Question 47

What is the average time to full oral feeding in an uncomplicated duodenal atresia case?

Answer 47

The average time to full oral feeds in an uncomplicated case of duodenal atresia is 10 days.