Congenital duodenal stenosis

　　One, Etiology

　　1. Incomplete cavitation during embryonic development:Normal intestinal development goes through three stages: luminal开通, epithelial cell proliferation, and re- cavitation. When the embryonic intestinal tract develops abnormally in the second or third month, with cavities forming but not fully merging, luminal stenosis occurs.

　　2. Intestinal blood circulation disorders during fetal stage:If the midgut from the umbilical vesicle returns to the abdominal cavity during the 10th to 12th week of embryogenesis and encounters an early contraction of the umbilical ring, it can lead to poor intestinal blood circulation; developmental defects or malformations in the nutritional blood vessels of the small intestine can also cause developmental disorders of the small intestine, leading to luminal stenosis.

　　Two, Pathogenesis

　　The most common narrow area is the lower segment of the duodenum. The degree of intestinal lumen narrowing varies, and the continuity of the intestinal tract is not lost. There is a circumferential hyperplasia in the duodenal lumen, with mild luminal obstruction, but no expansion function, leading to a slower course of disease. Over time, the proximal intestinal segment forms a giant duodenum. Some are diaphragm type, with a larger central opening; also, some duodenal stenosis has a narrowing segment near the common bile duct and pancreatic ampulla.

　　Microscopic examination of tissue sections shows that the stenotic band is composed of mucosa and fibrotic submucosal tissue. The proximal intestinal segment is dilated but does not cause ischemia, necrosis, or perforation.

　　Due to repeated vomiting, children may experience water and electrolyte imbalance. In cases with a long course, children may develop malnutrition, manifested as emaciation or anemia, etc.

　　Malnutrition is caused by insufficient intake of energy and (or) protein, leading to poor nutritional status or inability to maintain normal growth and development, mainly seen in children under 3 years old.

　　Anemia refers to a common clinical symptom in which the volume of red blood cells in the peripheral blood of the human body is reduced below the lower limit of the normal range. Since the measurement of red blood cell volume is complex, it is often replaced by hemoglobin (Hb) concentration in clinical practice.

　　When there is duodenal atresia, pregnant women in the early stage of pregnancy may have phenomena such as viral infection, vaginal bleeding, and often have polyhydramnios. The baby will have frequent vomiting within a few hours after birth, with a large amount of bile. If the obstruction is near the ampulla, it does not contain bile. There is no normal meconium excretion, or a small amount of white mucous or greasy-like material may be excreted. However, there may also be 1-2 times of small gray-green feces. The symptoms of severe stenosis are similar to atresia, while those with mild stenosis may have intermittent vomiting within a few weeks or months after birth, or even start vomiting several years later. As it belongs to high obstruction, there is generally no abdominal distension, or only mild upper abdominal bulging. Gastric peristalsis waves are rare. Due to severe vomiting, there is obvious dehydration, acid-base imbalance, and electrolyte disorder, leading to emaciation and malnutrition.

　　1. Develop good living habits, quit smoking and limit alcohol. Smoking, according to the World Health Organization, if people stop smoking, cancer in the world will decrease by 1/3 after 5 years; secondly, do not drink excessively. Cigarettes and alcohol are extremely acidic substances, and people who smoke and drink for a long time are prone to acidic体质.

　　Do not eat too much salty and spicy food, do not eat overheated, cold, expired, or deteriorated food; for the elderly, the weak, or those with certain genetic diseases, eat some anti-cancer foods and alkaline foods with high alkaline content appropriately to maintain a good mental state.

　　The X-ray erect anteroposterior film examination can show a large liquid level in the upper left abdomen, and a liquid level is also present in the upper right abdomen. This is the dilated stomach and the proximal duodenum. The other parts of the entire abdomen have no gas, forming a 'double bubble sign'. This is a typical X-ray sign of duodenal atresia. The flat film of duodenal stenosis is similar to atresia, but the proximal duodenum is less dilated, the liquid level is slightly smaller, and a small amount of gas can be seen in the rest of the abdomen. It is contraindicated to perform barium meal examination in neonatal intestinal obstruction, as it can cause fatal aspiration pneumonia of barium liquid. Sometimes, to differentiate from malrotation of the intestines, barium enema can be performed to observe the position of the cecum and ascending colon, but in fact, it is not necessary, as the findings of abdominal flat film can already confirm the diagnosis.

　　The general principle is soft and easily digestible diet, regular diet, ensure three meals a day, do not eat too much or too little, do not drink alcohol, tea, coffee, do not drink milk, do not smoke, do not eat stimulating things such as chili and garlic, do not eat overly sour or salty foods. Do not eat spicy and刺激性 food (chili, seafood, alcohol), do not eat cold and hard food (try to eat less rice and fried food), eat easily digestible noodles, eat more vegetables and fruits (boiled with water and then eaten), drink more water, exercise more. Try to eat less sweets and acidic foods.

　　1. Treatment

　　After the diagnosis is confirmed, surgery should be performed immediately. The preoperative preparation and anesthetic selection are the same as those for duodenal atresia, and anemia and dehydration should be corrected as much as possible before surgery. The operation usually adopts gastrojejunal anastomosis, duodenal jejunal anastomosis, or double anastomosis. The therapeutic effect of surgery is better than that of congenital atresia.

　　For patients with proximal duodenal obstruction, surgery should be performed through a right upper abdominal transumbilical transverse incision, which has good exposure of the surgical field and is convenient for a full abdominal exploration. The abdominal straight muscle is cut with an electrosurgical knife, and after entering the peritoneal cavity, the dilated duodenum is often exposed on the incision.

　　For children with duodenal stenosis and diaphragm formation, a gastrostomy tube should be placed before cutting the proximal duodenum. If there is a diaphragm, the catheter will adhere to it, and the catheter may fold during aspiration. If there is a windbag-like diaphragm, the tip of the catheter can feel inserted further, but often there is a folding phenomenon at the attachment site of the windbag-like diaphragm. When such a diaphragm exists, the incision should be made longitudinally from the proximal end to the possible attachment site of the diaphragm. Expand the incision beyond the attachment site of the diaphragm. At this time, one should be very careful and cautious because the Vater ampulla often accompanies these diaphragms. The diaphragm incision should be made in a radial incision to avoid injury to the ampulla. The Vater ampulla can be retained in the duodenal lumen as a lobular flap structure, and the duodenal incision can be closed laterally in the Heineke-Mikulicz manner.

　　Pay attention to explore whether there are other malformations during surgery.

　　2. Prognosis

　　The therapeutic effect of surgery is better than that of congenital atresia.