Intestinal intussusception

　　First, etiology

　　As the name implies, intussusception refers to one part of the intestinal tract being pulled into another segment of the intestinal tract. The principle of naming is to place the name of the proximal intussusception segment at the beginning, followed by the name of the distal sheath segment, for example, ileocecal type refers to the ileum being pulled into the colon. More than 80% of intussusceptions are ileocecal type, followed by ileoileal, cecum-cecum, cecum-ileum, and jejunojejunal types. Since the mesentery of the proximal intestinal segment is also pulled into the distal intestinal lumen, the mesenteric vessels are compressed, leading to venous return obstruction and intestinal wall edema. If not immediately reduced, intestinal necrosis can occur due to insufficient arterial blood supply, which may eventually lead to sepsis and death if not treated promptly.

　　Intussusception is divided into primary and secondary types.

　　1. Primary intussusception

　　90% of intussusceptions are primary, with no significant organic lesions in the involved intestinal segments and surrounding tissues. Intussusception can have a starting point, and as the intestines move, the proximal intestinal segment is pulled into the distal intestinal lumen. Almost all patients can find an enlarged intestinal wall lymph node at the head of the involved intestinal segment during surgery. Intussusception usually occurs after upper respiratory tract infection or gastroenteritis, with more than 50% related to adenovirus and rotavirus infections, which also explains the reason for the enlargement of Peyer's patches. The enlarged Peyer's patches protruding into the intestinal lumen may be the trigger for the onset of intussusception.

　　2. Secondary intussusception

　　Intussusception with an obvious pathological abnormality at the starting point accounts for 2% to 12%, including: Meckel diverticulum, appendix, polyps, tumors, submucosal hemorrhage caused by allergic purpura, non-Hodgkin's lymphoma, foreign bodies, ectopic pancreas or gastric mucus, intestinal duplication anomaly, etc., among which Meckel diverticulum is the most common. The older the age of onset in children, the greater the possibility of secondary intussusception.

　　Patients with cystic fibrosis are prone to intussusception and may have recurrent episodes, so multiple reductions are required. The possible causes include the concentration of intestinal secretions and the formation of fecal stones, which are more common in children aged 9 to 12 years.

　　Second, pathogenesis

　　Intestinal intussusception generally involves the proximal intestinal segment being pulled into the distal intestinal segment. If the distal segment pulls into the proximal segment (referred to as retrograde intussusception), it is relatively rare. The vast majority are solitary intussusceptions, and it is occasionally seen that multiple intussusceptions occur simultaneously.

　　1. Paroxysmal abdominal pain accompanied by distension and vomiting, the child will be restless and crying, pale and sweating;

　　2. Blood in the stool, mostly jam-like blood, sometimes accompanied by blood on the gloves during rectal examination;

　　3. The abdomen can be palpated for a sausagelike mass, or it may be active and painful. The mass of the ileocecal type is located above the umbilicus on the right side and a feeling of emptiness in the lower right abdomen.

　　Commonly seen in overweight and strong infants and young children under 2 years old, it is an acute onset. Intussusception can cause abdominal colic, and the previously calm child may suddenly appear restless and uncomfortable, with stiffness of the whole body, the legs屈曲 towards the abdomen, a painful expression, and symptoms that start and stop suddenly; infants who cannot express themselves may have paroxysmal crying and screaming, with normal or quiet sleep during the intervals. As the condition progresses, the intervals of abdominal pain may appear apathetic, drowsy, common vomiting, starting with indigestible food, followed by bile-like substances, and after vomiting, there may be whole-body twisting and gasping. In the early stage of intussusception, the colonic peristalsis increases, the intraluminal pressure rises, and the child excretes a small amount of normal feces. In the later stage, bloodstains appear in the feces, followed by dark red blood clots or jam-like feces due to ischemic necrosis.

　　1. Dietary changes and complementary food stimulation

　　The period of infancy is a period of great changes in the rhythm of intestinal peristalsis, which is prone to intestinal peristalsis disorder. Moreover, there are many factors that can cause intussusception, such as the addition of complementary foods or changes in the nature of food, environment, and temperature, and intestinal diseases such as enteritis, which can induce intestinal peristalsis disorder and cause intussusception.

　　2. Local anatomical factors

　　The ileocecal region in infants and young children is more mobile, and the ileocecal valve is lip-like convex into the cecum. When the peristalsis of the ileum occurs abnormally, it can pull the intestinal wall to form an intussusception.

　　3. Viral infection or other causes

　　Factors causing enlargement of the ileocecal lymph nodes: After infection with adenovirus or rotavirus in children, it can cause hyperplasia of the terminal ileal lymph nodes, thickening of the local intestinal wall, and even the formation of a mass protruding into the intestinal lumen to form the starting point of intussusception. In addition, due to viral infection or other reasons, the intestinal peristalsis is enhanced, leading to the onset of the disease.

　　4. Unbalanced immune response factors

　　Primary intussusception often occurs in children under 1 year old, which is exactly the period when the body's immune function is not perfect. Local immune function in the intestinal wall is easily damaged, leading to peristalsis disorder and triggering intussusception. Secondary intussusception often occurs due to organic lesions in the intestinal wall or lumen, such as intestinal polyps, tumors, intestinal wall hematoma, Meckel diverticulum, intestinal cysts, etc., which cause intussusception by pulling the intestinal wall as the starting point. The incidence rate is about 2% to 5%.

　　Blood tests may show an increase in peripheral blood leukocytes, which can also be normal; in severe shock and dehydration, there may be water and electrolyte disorders, metabolic acidosis, and positive occult blood test in feces.

　　1. Apple Diet

　　Apples contain tannins and have astringent effects. Wash an apple, steam it, and eat the flesh or peel it and mash it into a paste for consumption. The recommended dosage is 30 to 60 grams per time, taken three times a day. Apple soup is also an auxiliary beverage for treating diarrhea. Cut the apple into pieces, add 250 milliliters of water and a small amount of salt, and you can also add 5% sugar. Boil the mixture as a tea substitute. It is suitable for infants under 1 year old.

　　2. Yolk Diet

　　Boil the eggs, remove the shell and the yolk, and cook the yolk in a pot over low heat to extract the oil. For infants under 1 year old, take one yolk oil per day, divided into 2-3 doses, for 3 days as a course of treatment, for diarrhea, and has the effect of invigorating the spleen and stomach to stop diarrhea; steamed egg cakes made with a little flour and ginger slices also have the same effect.

　　3. Chestnut Paste Diet

　　Use 3-5 chestnuts, remove the shell and crush them, boil them in water to make a paste, add sugar to taste, eat 2-3 times a day, with the effect of warming and stopping diarrhea.

　　1. Treatment

　　If the child has symptoms of shock or peritonitis, or if the enema reduction fails, exploratory laparotomy is required. Preoperative measures such as gastric decompression, intravenous fluid administration, and prophylactic antibiotic use should be taken. During the operation, it is necessary to explore whether there are organic lesions that can induce intussusception. The recurrence rate of intussusception is 2%-20%, of which about 1/3 occur on the day of the first onset, and most occur within 6 months. Recurrence is often without a fixed intussusception site, and the same patient can have multiple recurrences. There are fewer recurrences in those who undergo surgical reduction or intestinal resection. The success rate of enema reduction in recurrent intussusception without a history of surgical treatment is almost completely the same, even slightly higher. Recurrence patients usually seek medical attention earlier, with milder symptoms, mainly manifested as discomfort and irritability. It should be noted that recurrent intussusception should consider the possibility of intestinal lesions. There is a possibility of secondary intussusception after thoracoabdominal surgery. When children show signs of intestinal obstruction after surgery, it is often first thought of as绞窄性肠梗阻, so it is rarely diagnosed as intussusception before reexploration. Most postoperative intussusception occurs within 1 month after surgery, with an average of about 10 days. Contrast examination is helpful for diagnosis and can manifest as small bowel obstruction. Postoperative intussusception is mostly ileal ileal type, requiring surgical reduction, but not requiring intestinal resection.

　　2. Prognosis

　　If infantile primary primary intussusception can be diagnosed early, early enema reduction can be cured. If the course of the disease exceeds 1-2 days, especially if there are symptoms such as severe dehydration, poisoning, or shock, most often require surgical reduction or intestinal resection, with a significantly increased mortality rate, reaching 2%-5%.