Duodenal atresia is an obliteration of the lumen of the duodenal canal, which causes congenital intestinal obstruction. It occurs in the period of embryonic development, is provoked by teratogenic effects and is often accompanied by other gastrointestinal defects. Signs of duodenal obstruction appear from birth and include repeated vomiting, lack of meconium, prolonged jaundice. Ultrasound of pregnancy, cordocentesis, gastrointestinal radiography in the postnatal period are used for diagnosis. Treatment of atresia is surgical, in most cases the operation is performed in the first 48 hours of the newborn period.
Q41.0 Congenital absence, atresia and duodenal stenosis
Duodenal atresia is the most common variant of congenital malformation, which accounts for up to 50% of cases of intestinal obstruction. Pathology is diagnosed in one newborn per 7-10 thousand live-born babies. In 30% of cases, it is combined with Down syndrome and other congenital malformations, so it is of great interest not only for pediatric surgery, but also for clinical genetics. Severe manifestations of duodenal atresia necessitate the improvement of its early diagnosis and adequate correction.
Causes of duodenal atresia
The appearance of atresia is associated with disorders of the laying and development of the gastrointestinal tract in the first trimester of pregnancy. Etiological factors have not yet been established. Previously, scientists discussed the idea of the influence of burdened heredity, but when analyzing the medical histories of patients with duodenal atresia, this theory could not be confirmed. It is assumed that the anatomical anomaly is caused by the action of teratogenic factors and is associated with other malformations.
Pathology is formed in the period from 5 to 12 weeks of intrauterine development of the embryo. During this time period, the duodenum (duodenum) undergoes a stage of complete overgrowth (obliteration) of the lumen. After vacuolization is completed, the intestinal tube is normally recanalized. In violation of the physiological process of embryogenesis, atresia develops at different heights of the duodenum 12. This variant of pathology is called internal atresia.
In rare cases, an external duodenal obstruction is formed, which is associated with compression of the intestine from the outside. Such cases can be triggered by the annular pancreas, which covers the descending part of the duodenum. Isolated cases of atresia with compression of the intestinal tube by a malroted portal vein are described.
Atresia of the 12-pert intestine causes severe digestive disorders already in the intra-tube period. With high intestinal obstruction in the fetus, the amniotrophic type of nutrition is disrupted, which consists in the absorption of nutrients from the amniotic fluid. This leads to insufficient body weight, delayed intrauterine development, and an increased risk of hypoxia. A particular danger is a high obstruction of the gastrointestinal tract.
In the postnatal period, all violations are aggravated. Duodenal atresia is characterized by a large loss of fluid and electrolytes, causing hydroionic disorders. Gastric atony manifests itself, which begins to form during the fetal period. In children, no more than 60% of smooth muscle gastric fibers are detected, which becomes the cause of low intragastric pressure and delayed evacuation of food masses even after surgical correction of atresia.
According to the mechanism of development, the internal and external forms of the defect are distinguished. Preampular and postampular forms are isolated at the site of obstruction of the 12-duodenum. The latter is much more common, accounting for up to 85% of cases of all duodenal atresia. In practical surgery, the classification of congenital malformation according to morphological features into 3 types is of the greatest importance:
- Type I. A frequent variant of duodenal atresia, which is characterized by the presence of a membrane covering the lumen of the intestinal tube. The muscle wall has a normal structure, it is continuous in the adductor and abductor sections.
- Type II. It is characterized by complete overgrowth of the lumen of the duodenum 12 in the form of a fibrous cord that connects two blindly ending segments of the digestive tube. These departments do not have a continuous muscular sheath, unlike type I.
- Type III. The rarest variant of the anomaly, in which the segments of the duodenum are completely disconnected. It is often accompanied by multiple atresia of the digestive tract and is characterized by an unfavorable course.
Duodenal atresia symptoms
Complete obliteration of the intestinal lumen causes a vivid clinical picture from the first hours of the newborn’s life. The main sign is repeated vomiting. When the atresia is located below the fater’s nipple, the vomit becomes yellowish-green in color, since bile is present in them. With high duodenal obstruction, vomiting with colorless contents is observed, when trying to feed the baby with curdled milk.
A characteristic sign of the disease is the absence of meconium in the first day of life, which is observed in 70% of children. More than 40% of infants suffer from pathological jaundice. It is caused by a violation of bilirubin metabolism and increased secretion of glucuronidase into the intestine, an enzyme that binds bilirubin. Against the background of vomiting and lack of enteral nutrition, signs of dehydration increase, convulsions, drowsiness and other neurological symptoms are possible.
Duodenal atresia is an extremely dangerous condition that makes it impossible to feed a baby and quickly leads to critical dehydration. Violations of water-electrolyte metabolism are manifested by the sinking of the fontanelles, prolonged crying without tears, sharp and scanty urination. In the absence of correction of fluid loss, progressive depression of consciousness is observed up to coma. The condition is aggravated by protein-energy deficiency.
In 2.1-4.4% of cases, duodenal obstruction is combined with esophageal atresia. The combination of two malformations is called midline syndrome. Pathology has an unfavorable course and is difficult to reconstructive operations, besides, there is a high risk of complications in the rehabilitation period. In this regard, the combined defect is characterized by high lethality.
In some children, complications occur in the postoperative period. The most frequent consequence of surgical correction of atresia of the duodenum is considered to be gastrointestinal reflux, which increases the risk of esophagitis. Occasionally, megaduodenum is observed – an expansion of the proximal duodenum, which is associated with disorders of the motor function of the digestive tract.
Modern imaging methods make it possible to detect pathology even in the prenatal period. The defect is fully formed by approximately 12-14 weeks of antenatal development, which coincides with the time of the first pregnancy screening. The following methods are used for prenatal determination of duodenal atresia:
- Ultrasound of pregnancy. Echosonography determines the pathognomonic sign of duodenal atresia – a symptom of a double bladder. It consists of two levels of fluid accumulation located in the stomach and the initial part of the intestine. Polyhydramnionia is often detected.
- Cordocentesis. An invasive study is prescribed if combined developmental abnormalities are suspected, which may be a manifestation of one of the chromosomal abnormalities, primarily Down syndrome. The resulting material is used for karyotyping of the fetus.
Postnatal diagnosis of pathology begins with the identification of a characteristic clinical picture. To confirm the diagnosis, differentiation of the complete and partial forms of duodenal obstruction, an overview abdominal x-ray of a newborn is prescribed. The image shows the sign of a double bubble described above. To assess the severity of homeostasis disorders, clinical and biochemical blood tests are performed.
Duodenal atresia treatment
Surgery is the only way to restore the patency of the intestinal tube. If the diagnosis was made prenatally, the intervention is planned for a period of 24-48 hours after the birth of the baby, provided that he feels well. If atresia of the duodenum is diagnosed later, it is necessary to replenish the water-electrolyte balance and normalize the patient’s condition before the operation.
With type I obstruction, it is possible to dissect the duodenal membrane without anastomosing. In other cases, an anastomosis is applied to ensure the passage of food masses through the intestines. Operations are performed in two ways: laparotomy (classical incision) and laparoscopy (minimally invasive technique). The second option has advantages due to the panoramic visualization of the surgical field, less trauma and better functional result.
Surgical treatment is supplemented with infusion therapy, the volume and composition of which is determined taking into account laboratory data. Parenteral administration of nutritional mixtures is prescribed to feed the child until the gastrointestinal tract is restored. According to the indications, the replacement of hypovitaminosis, correction of other perinatal or congenital pathologies is carried out.
Prognosis and prevention
With isolated duodenal atresia, the prognosis is relatively favorable, especially with prenatal diagnosis of the problem and successful elective surgery. Serious concerns of doctors are caused by combined atresia of the duodenum and esophagus, the mortality rate of which can reach 50%. Adequate measures for the prevention of pathology have not been developed. For early detection of pathology, pregnant women need to follow the schedule of screenings and visits to the women’s clinic.
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