Duodenal Atresia Flashcards
What is duodenal atresia?
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.
What is meant by “intestinal atresia”?
Intestinal atresia refers to a congenital obstruction of the intestinal lumen, caused by a structural abnormality in the intestinal wall.
What are the types of pathology associated with intestinal atresia?
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
What happens to the duodenal lumen during embryonic development
Between the 5th and 8th weeks of embryonic life, the duodenal lumen passes through a solid phase.
What could cause duodenal atresia during embryogenesis?
Disruption in the normal cannulation of the duodenal lumen due to an unknown embryological insult during the second month of pregnancy.
Why is it suggested that duodenal atresia is due to an early insult during embryogenesis?
Because of the frequent coexistence of other anomalies, suggesting that the insult affects the embryo as a whole.
What is the incidence of duodenal atresia?
The incidence is 1:3400 live births, and it occurs equally in males and females.
What biliary abnormalities can be associated with duodenal atresia?
• Bifid pancreatic duct
• Annular pancreas (pancreatic tissue surrounding the second part of the duodenum)
What is the association between duodenal atresia and Trisomy 21?
Duodenal atresia is highly associated with Trisomy 21 in approximately 30% of cases.
What is duodenal stenosis and how does it differ from duodenal atresia?
• 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.
Where do most congenital duodenal obstructions occur?
Most congenital duodenal obstructions occur in the second part of the duodenum and are considered periampullary.
How does the biliary outlet relate to the site of duodenal obstruction?
In most cases, the biliary outlet occurs either proximal or distal to the site of duodenal obstruction.
What radiological feature is typical for congenital duodenal obstruction?
The typical radiological feature is a ‘double bubble’, caused by the dilation of the proximal duodenum and stomach.
What is a common finding in the antenatal diagnosis of duodenal atresia?
Polyhydramnios is present in 40% of cases.
What growth abnormality is often seen antenatally in duodenal atresia?
Growth retardation is commonly observed.
What antenatal ultrasound findings are indicative of duodenal atresia?
Dilated stomach and dilated first part of the duodenum on ultrasound.
What ultrasound features might suggest Trisomy 21 antenatally in duodenal atresia cases?
Ultrasound features of Trisomy 21 may be present in approximately 25% of cases.
How does antenatal detection benefit the management of duodenal atresia?
Antenatal detection enables planned in-utero transfer and delivery at a tertiary unit with neonatal ICU and paediatric surgical expertise.
What percentage of babies with duodenal atresia are born prematurely?
50% of babies with duodenal atresia are born prematurely.
What is the typical vomiting pattern in duodenal atresia?
• 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.
What physical sign is commonly observed in babies with duodenal atresia?
Epigastric distension is commonly seen.
How does the passage of meconium differ in babies with duodenal atresia?
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.
What biochemical abnormalities are associated with duodenal atresia?
Due to ongoing vomiting of upper gastrointestinal contents, there is a hypochloraemic, hyponatraemic metabolic alkalosis.
What percentage of infants with duodenal atresia develop jaundice?
Approximately 40% of infants with duodenal atresia develop jaundice, often due to disrupted enterohepatic circulation or sepsis.
What is the first imaging study that should be performed in all cases of duodenal atresia?
An abdominal x-ray should be performed in all cases.
How can the typical “double bubble” appearance be enhanced on an abdominal x-ray?
The typical ‘double bubble’ appearance can be enhanced by introducing air via a nasogastric tube.
When is a contrast meal and follow-through essential in the diagnosis of duodenal atresia?
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.
How can midgut volvulus be differentiated from duodenal atresia on imaging?
Midgut volvulus should be suspected if the proximal dilated bowel appears beaked rather than rounded on x-ray or contrast imaging.
What is the association between duodenal atresia and Trisomy 21 (Down syndrome)?
30% of babies with duodenal atresia have Trisomy 21 (Down syndrome).
What physical features should you look for to identify possible Trisomy 21 in a baby with duodenal atresia?
• 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
What are the initial steps in preparing a baby with duodenal atresia for surgery?
• 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
What respiratory support might be needed for a baby with duodenal atresia?
Oxygen via nasal cannula or intubation if the baby is distressed.
What should be closely monitored in a baby preparing for surgery?
Cardiovascular, respiratory, and metabolic status should be closely monitored.
What is the most urgent differential diagnosis to consider in babies with duodenal atresia?
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.
How can gastro-oesophageal reflux be distinguished from duodenal atresia?
Gastro-oesophageal reflux causes persistent milk vomiting that can turn bile-stained, but it rarely leads to biochemical abnormalities.
What radiological findings differentiate jejuno-ileal atresias or other obstructions from duodenal atresia?
Jejuno-ileal atresias or other causes of obstruction would show a different radiological picture, but may also cause bile-stained vomiting and sepsis.
When is surgery typically performed for duodenal atresia?
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).
When is immediate surgery necessary for a baby with duodenal atresia?
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.
What should be done if there is a delay before surgery for duodenal atresia?
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.
What is the typical approach for duodenoduodenostomy surgery?
The surgery is typically performed via a transverse laparotomy, though it may also be done laparoscopically in some institutions.
How is the duodenal obstruction bypassed in duodenoduodenostomy surgery?
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.
What post-operative care is required in the early period after duodenoduodenostomy surgery?
• 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.
How should oral feeding be initiated post-operatively for duodenal atresia?
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.
What is a common complication in the early post-operative period for duodenal atresia patients?
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.
What long-term concerns should be monitored for duodenal atresia patients post-surgery?
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.
What is the average time to full oral feeding in an uncomplicated duodenal atresia case?
The average time to full oral feeds in an uncomplicated case of duodenal atresia is 10 days.
