Table of Contents
Definition and Background
An atresia is a complete obstruction of the lumen of a hollow viscus.
Duodenal atresia is a congenital defect of the gastrointestinal tract characterized by the complete absence of the lumen of the duodenum (the first part of the small intestine), which makes the absorption and the passage of food through the digestive canal impossible, causing duodenal obstruction.
In duodenal stenosis, there is partial narrowing (stenosis) of the lumen of duodenum. It is associated with variable and delayed manifestations, followed by concealed symptoms at the beginning, and may last up to adulthood.
Etiology & Pathophysiology of Duodenal Atresia
Although the exact etiology of duodenal atresia is not known as the most cases are sporadic. However, it is suggested that during early weeks of gestation (6 and 7 weeks), the endodermal epithelium proliferates and the portions of the gastrointestinal tract lumen become occluded. The recanalization normally occurs during 8 – 10 weeks of gestation and the lumen patency is restored. The failure to recanalize due to any reason results in atresia. One of the suggested reasons for the recanalization failure is hypoxia of the fetus during the early stages of embryogenesis (ischemic episode).
Epidemiology of Duodenal Atresia
Duodenal atresia is a relatively common congenital anomaly of the gastrointestinal tract occurring 1 in 2,500-40,000 live births. The one-third of these cases are associated with Down syndrome (trisomy 21). There is no racial or gender propensity, with equal incidence in both males and females.
There is a pattern for intrinsic inborn duodenal obstructions:
- Duodenal atresia, 40-60%;
- Duodenal web, 35-45%;
- Annular pancreas, 10-30%;
- Duodenal stenosis, 7-20%.
Presentation of Patients with Duodenal Atresia
In 85% cases of complete duodenal atresia, bilious vomiting occurs during the first hours of life. The color of the vomitus is yellow-green and sometimes with brown granular matter. In the rest of the cases (15%), it may be non-bilious as the atresia occurs proximal to the ampulla of Vater.
On physical examination, the abdomen is sunken (scaphoid abdomen). There may be epigastric fullness due to distension of stomach and proximal duodenum. Although the bowel movements are absent due to high intenstinal blockage, the meconium passage is not affected during the first 24 hours after birth. The affected newborn may be small for gestational age.
The congenital intestinal defects that are associated with bilious vomiting and the time of manifestation are:
- Duodenal atresia, a few hours after birth, no distention;
- Malrotation with volvulus, at 3 to 7 days, rapid deterioration with volvulus;
- Jejunoileal atresia, during the first hours of birth, abdominal distention;
Partial duodenal atresia (stenosis) symptoms depend on the severity of the defect. The illness may not show any symptoms for months and years and usually manifests with long-lasting vomiting, constipation, food aspiration, and failure to thrive. The constipation is unresponsive to the treatment.
The duodenal atresia or stenosis may be an isolated finding but most commonly they are associated with other congenital defects such as:
- Down syndrome (most common and present in 25-40% of cases)
- VACTERL association
- Annular pancreas
- Anal atresia
- Ileal atresia
- Jejunoileal atresia
Differential Diagnosis of Duodenal Atresia
Plain radiograph appearance Duodenal stenosis
Ultrasound appearance of a “double bubble type” (distal gas) Fetal choledochal cyst
Fetal omental cyst
Fetal duplicated cyst
Diagnosis of Duodenal Atresia
Radiography is an informative method of examination in duodenal atresia. It finds dilated stomach and the first part of the duodenum (“double bubble”), and the absence of air behind the second bubble. This finding of double bubble sign with no distal gas strongly suggests duodenal atresia.
Ultrasonography is efficient in the prenatal diagnosis of duodenal atresia, apart from the specific appearance of the abdomen; there is polyhydramnios, which is a prominent symptom of the defect. Ultrasonography is preferred in esophageal and duodenal atresia.
Barium enema examination is an additional study that makes distant duodenal atresia as well as malpositioned cecum evident. However, in the diagnostics of malrotation and volvulus, barium enema is not that informative.
No laboratory studies are diagnostic of duodenal atresia. However, laboratory studies help in the assessment of the infant’s overall clinical condition.
- Blood glucose may be low in premature babies; they tend to develop hypoglycemia as there is a limited supply of glycogen.
- Serum electrolytes have to be determined as infants with duodenal atresia tend to lose fluids and electrolytes produced by the stomach, due to a large amount of gastric aspiration.
- Karyotype analysis is the appropriate method of examination in the case of trisomy 21.
- Immunohistochemistry of proximal and distal duodenal samples of affected infants reflects changes and transformation of neuronal cells, intestinal cell Cajai, hypertrophy of circular muscles. All of these witness about the persistent disorder of the duodenal movement after primary surgery.
- Measurement of gastric aspiration. Normally, it should not exceed 5 ml. Duodenal atresia is suspected when an infant’s gastric aspiration is greater than 30 ml. Fullness of the epigastrium may be detected manually and visually, when the food gets stacked above the narrowed lumen.
- Rectal biopsy conducted in order to exclude Hirschsprung disease, especially in patients with Down syndrome.
- Hematocrit has to be checked prior to general anesthesia.
- Blood type and cross match.
- Arterial blood gas measurements are needed if the infant has aspirated or shows signs of respiratory distress.
Management of Duodenal Atresia
There is no conservative treatment available for this condition.
Type of duodenal obstruction Preoperative management Surgical treatment Postoperative period Prognosis Duodenal atresia IV fluids hours and nasogastric suction 24-48 hours Diamond-shaped duodenostomy No feeding per os for 2-4 days after operation; nasogastric suction. Benign, if there are no serious associated congenital defects Jejunoileal atresia IV fluids, STAT surgery for the patients with obvious symptoms; nasogastric suction Ladd’s procedure: sometimes a second laparotomy is required No feeding per os; nasogastric suction Benign, if there is no large bowel resection Jejunoileal atresia IV fluids and nasogastric suction for 24-48 hours Resection and anastomosis No feeding per os for 2-4 days after operation; nasogastric suction. Benign, if there is no large loss of the bowel
In spite of the benign prognosis after the surgery, 22% of babies may develop distant complications: