Intestinal atresia
Tip
The pathophysiology of intestinal atresia varies based on the segment of bowel involved.
In duodenal atresia, the mechanism involves failure of the lumen to recanalize after epithelial proliferation in the first trimeste.
In contrast, intestinal atresia of the midgut (eg, jejunum, ileum, proximal colon) is the result of vascular occlusion in utero.
Duodenal atresia
- Definitions
- Duodenal atresia is the complete occlusion or absence of the duodenal lumen.
- Duodenal stenosis is an incomplete obstruction caused by narrowing of the lumen.
- Epidemiology
- 20–25% of cases are associated with chromosomal abnormalities, especially Down syndrome.
- Pathophysiology
- Since the development of the duodenum is connected to the growth of the pancreas and the hepatobiliary system, duodenal atresia is also commonly associated with anomalies of these organs.
- Clinical features
- Intrauterine: polyhydramnios
- Duodenal stenosis or atresia prevents the fetus from swallowing and passing amniotic fluid.
- Postpartum
- Vomiting that is typically bilious
- Distended upper abdomen and scaphoid lower abdomen
- Delayed meconium passage
- Intrauterine: polyhydramnios
- Diagnostics
- Prenatal: ultrasound; Postnatal: x-ray
- Double bubble sign
- Air and fluid build up proximal to the obstruction and are separated by the pyloric sphincter, which resembles two bubbles on imaging, one in the stomach and one in the duodenum.
- If present, test for associated anomalies (e.g., karyotyping, microarray)
- Air and fluid build up proximal to the obstruction and are separated by the pyloric sphincter, which resembles two bubbles on imaging, one in the stomach and one in the duodenum.
- Gasless distal bowel
- Double bubble sign
- Prenatal: ultrasound; Postnatal: x-ray
Jejunal atresia
- Definition: absence of the jejunal or ileal lumen
- Etiology
- Associated with cystic fibrosis
- Risk factors: maternal smoking and/or use of vasoconstrictive agents (e.g., cocaine, MDMA) during pregnancy
- Pathophysiology: vascular accident in utero (usually a disruption of superior mesenteric artery) → ischemic necrosis and reabsorption of the jejunum or ileum → discontinuous bowel → obstruction
- Clinical features: similar to duodenal atresia
- Polyhydramnios (intrauterine)
- Bilious vomiting and upper abdominal distention (postpartum)
- Diagnostics: Abdominal x-ray shows a triple bubble sign (dilated small bowel loops and air-fluid levels; the three bubbles correlate with the distended stomach, duodenum, and jejunum proximal to the obstruction) and gasless colon.
Differential diagnostics
