What is the most accurate description of duodenal atresia?

Duodenal Atresia: Characteristics and Associations

Duodenal atresia is rarely associated with intrauterine mesenteric vascular accidents, commonly exhibits a mucosal web with normal muscular wall, frequently prevents normal passage of meconium at birth, and is commonly associated with other congenital anomalies, particularly trisomy 21. 1, 2

Etiology and Pathophysiology

• Duodenal atresia results from failure of recanalization of the primitive gut lumen during embryologic development, not from intrauterine mesenteric vascular accidents (which is the mechanism for jejunoileal atresia) 3
• The condition commonly presents as a mucosal web with normal muscular wall (type I atresia), rather than complete separation of duodenal segments 4, 2

Clinical Presentation

• Bilious vomiting within the first 2 days of life is a common presentation due to proximal intestinal obstruction 4, 3
• Abdominal distension occurs due to accumulation of fluid and gas proximal to the obstruction 3
• Passage of meconium is typically absent or abnormal at birth due to the complete obstruction of the duodenum 3, 2

Diagnostic Features

• The classic "double bubble" sign on radiographs indicates proximal dilation of the duodenum and stomach, suggesting duodenal atresia 4, 2
• In cases with no gas distally, upper GI series is usually not necessary as the diagnosis is typically clear from plain radiographs 4
• Prenatal diagnosis is possible in approximately 48% of cases through routine ultrasonography at 20-week gestation 1

Associated Anomalies

• Duodenal atresia is frequently associated with other congenital anomalies (57% of cases), contrary to the statement that it is rarely associated with other anomalies 1
• There is a strong association with chromosomal abnormalities, particularly trisomy 21 (Down syndrome) 1, 2
• Other associated anomalies may include cardiac malformations, other gastrointestinal anomalies, and components of VACTERL association 1, 5
• The presence of associated anomalies significantly impacts mortality and long-term outcomes 1, 5

Management Considerations

• Surgical correction is the definitive treatment, with diamond-shaped duodenoduodenostomy (DDD) showing superior outcomes compared to other techniques 6
• Patients with prenatally diagnosed duodenal atresia have higher mortality rates and greater association with other congenital anomalies 1
• Long-term follow-up is recommended as late complications occur in approximately 12% of patients, with a late mortality rate of 6% 5

Differential Diagnosis

• Must be distinguished from jejunoileal atresia, which is caused by intrauterine mesenteric vascular accidents rather than failure of recanalization 3, 7
• Malrotation with midgut volvulus can present similarly with bilious vomiting but has a different embryologic cause 4, 3
• Hirschsprung disease, which results from neural crest migration failure, should also be considered in the differential diagnosis 3

The evidence clearly demonstrates that duodenal atresia is commonly associated with other congenital anomalies (particularly Down syndrome), typically presents with abnormal or absent passage of meconium, and commonly exhibits a mucosal web with normal muscular wall rather than being caused by intrauterine vascular accidents 1, 2.