Pediatric adhesive intestinal obstruction

　　One, Etiology

　　The formation of adhesions and bands can be divided into congenital and acquired categories:

　　1, Congenital Congenital adhesions and bands include adhesions after meconium peritonitis, bands due to malrotation of the intestines, and residual bands of Meckel's diverticulum, etc.

　　2, Acquired Acquired adhesions include postoperative adhesions, infiltrative tumors, tuberculous adhesions, and post-peritoneal inflammatory adhesions, etc. On this basis, obstruction can occur due to certain triggers. Adhesions can be caused by the following reasons.

　　(1) Injury: The serous membrane of the peritoneal intestinal wall is stimulated mechanically, such as surgical trauma, changes in temperature and humidity, and the stimulation of chemical drugs used during surgery, which can all cause adhesion.

　　(2) Infection: inflammatory adhesion caused by bacteria or other pathogens, such as chronic tuberculous peritonitis, where adhesion is produced simultaneously with the inflammatory process, and post-inflammatory adhesion after acute suppurative localized or diffuse peritonitis.

　　(3) Foreign body刺激性adhesion: such as adhesion caused by bleeding in the abdominal cavity, bile, meconium, and other drugs, as well as tumors that stimulate adhesion.

　　Two, Pathogenesis

　　The peritoneum has a strong ability to regenerate and repair. The adhesion between abdominal organs and peritoneum after abdominal surgery is a biological protective mechanism of the body against external stimuli. It can limit peritoneal inflammation and promote wound healing. On the other hand, peritoneal adhesion also brings the harm of adhesive intestinal obstruction. After the peritoneum is stimulated and injured, the initial stage is serous exudation, containing fibrin and fibrin deposition. This is due to the stimulation of mesothelial cells and deep mast cells, where mesothelial cells release thrombin activator, promoting the transformation of fibrinogen into fibrin, and mast cells release histamine, heparin, and vasoactive substances, causing capillaries to dilate and increase permeability, leading to serous exudation. In the intestinal tract, a thick and thin pus film forms within 6-12 hours, which is easy to separate into fibrinous adhesions. This adhesion is temporary; if surgery is performed again within 48 hours, it is easier to钝性分离. Without surgery, it usually dissolves spontaneously within 72 hours. If adhesions persist for more than 3 days and are not absorbed, they form firm fibrous adhesions. The key factor in this process is the fibrinolysis system. In the etiology of peritoneal adhesion, the inhibition of fibrinolytic activity is an important factor. Adhesion occurs when the activity of fibrinolytic enzyme activator drops below 60%. On the basis of fibrinous adhesion, collagen fibers are generated, forming fibrous adhesions and beginning to form a relatively dense vascular network, making separation difficult and prone to bleeding, which is about 1 week after the injury. The intestinal tract is fully adhered, and gradually begins to absorb due to intestinal peristalsis, making the space between intestines relatively loose, but still with membranous adhesions. This period is about 2-3 weeks after the injury. One month later, the adhesion further stretches and absorbs, forming multiple hollow defects, becoming adhesion bands, and further absorbing to form narrow and thick cord-like adhesions. The complete absorption of adhesions requires 1-1.5 years. Adhesive intestinal obstruction generally occurs in the small intestine, and it is extremely rare in the colon. Intestinal adhesions can exist for a long time, but usually without symptoms. The following conditions can produce adhesive intestinal obstruction:

　　Adhesions between the intestinal tube and the abdominal wall, with the intestinal loops folded into angles or twisted at the adherent parts, this situation often occurs below the incision.

　　The ends of the adhesion bands are fixed, compressing the intestinal tube and causing obstruction. It can also cause a part of the intestinal loop to be pulled into the ring hole, forming an internal hernia.

　　Part or most of the intestinal tube becomes adhered into a mass, with excessive folding and twisting of the intestinal tube, causing narrowing of the intestinal tube and forming incomplete or complete intestinal obstruction.

　　Adhesions between a segment of the intestinal loop and a distant location, such as the jejunum and pelvic adhesions, can pull the intestinal tube into a sharp angle, which can also cause intestinal obstruction. In these cases, it usually causes simple intestinal obstruction. If complications such as twisted bands or internal hernias affect blood flow, it forms strangulated intestinal obstruction. In addition, after eating, a large amount of intestinal content reaches the adhesion site, causing hyperperistalsis and can lead to intestinal torsion, which can also promote the formation of intestinal obstruction.

　　In summary, the formation of adhesions within the peritoneal cavity is related to individual factors of unknown causes. The adhesion fibers can be completely absorbed, and there are also extensive adhesions that form into clumps, with a few fiber bundles remaining after a long period of time. However, the occurrence of adhesions is significantly related to the degree of injury, the severity of foreign body stimulation, the intensity of physical stimulation, the use of antibiotics and other drugs in the abdominal cavity, and the overall condition of the body. The stronger the stimulation, the more adhesions are produced. Poor overall condition, such as low protein levels, will delay the recovery process. The pathological changes in the formation of adhesions are consistent. Initially, they are due to protective inflammatory reactions, with a large amount of fibrinogen exuding and becoming fibrin, which then settles on the peritoneum and serosa of the intestines, forming soft and extensive fibrous adhesions between intestinal loops. This adhesion substance is paste-like and can be gently separated without damaging the serosa of the intestines, usually causing few obstructions. In minor injuries, after inflammation subsides, most of this fibrin film is absorbed. In severe injuries, the fibrin film is not fully absorbed, and collagen fibers are gradually formed, leading to fibrous membrane adhesions. Through the peristalsis of the intestines, the remaining fibrous adhesion membranes are pulled and torn, leaving scar-like adhesions, or parts of the intestinal loops become tightly adhered in clumps, causing intestinal torsion, and intestinal lumen narrowing becomes the main pathogenic basis for adhesive intestinal obstruction in the future.

　　6. In summary, the production, absorption, and individual factors are related to the formation of intra-abdominal adhesions, and there is a great individual difference. However, the occurrence of adhesions is still related to the extent of injury, the amount of foreign bodies, the intensity of physical stimulation, the concentration of antibiotics used in the abdominal cavity, the virulence and number of bacteria, and the local blood circulation. The stronger the stimulation, the more adhesions produced. The longer the absorption and repair, even forming permanent sequelae due to malnutrition, low protein, and inability to absorb. On the basis of the existence of adhesions, any cause that stimulates the intestinal peristalsis to be hyperactive and rhythmical, such as cold, high fever, overeating, etc., can trigger the onset of acute intestinal obstruction. The proximal intestinal loop swells, the intestinal lumen is filled with gas and fluid, and the intestinal loop below the obstruction point becomes empty and shrinks without gas. If the local blood circulation of the intestinal tract is obstructed, intestinal necrosis will appear quickly, developing into diffuse peritonitis and toxic shock. Some may also perforate near the obstruction or necrosis.

　　One, Acidosis and Dehydration

　　Due to frequent vomiting and loss of a large amount of digestive fluid, and because of the inability to eat and fever, the child gradually develops dehydration and acidosis. The symptoms of dehydration in绞窄性肠梗阻 are usually severe from the beginning.

　　Two, Intestinal Perforation

　　1. Intestinal perforation is a pathological change in the intestines characterized by necrosis of the intestinal wall, leading to perforation in the end. After the intestinal contents enter the abdominal cavity, if it is small, it can be wrapped and localized by the omental sac inside the abdomen. If it is large, it will completely enter the abdominal cavity, causing severe abdominal pain, stiffening of the abdominal muscles, and may cause shock.

　　2. Abdominal pain from acute intestinal perforation often occurs suddenly,呈持续性剧痛，often making the patient difficult to bear, and it worsens during deep breathing and coughing.

　　3. The range of pain is related to the extent of peritonitis spread. The patient adopts a supine position, with the lower limbs flexed, and does not want to move. Abdominal examination shows significant weakness of respiratory movement, stiffening of the abdominal muscles, decreased or absent bowel sounds, reduced or disappeared liver dullness, and free gas under the diaphragm can be found by X-ray examination.

　　Three, Peritonitis

　　1. Peritonitis is a common severe surgical disease caused by bacterial infection, chemical irritation, or injury. Most of them are secondary peritonitis, originating from the infection of abdominal organs, necrosis and perforation, trauma, etc.

　　2. Its main clinical manifestations are abdominal pain, abdominal tenderness, abdominal muscle tension, as well as nausea, vomiting, fever, leukocyte elevation. In severe cases, it can lead to a decrease in blood pressure and systemic toxic reactions. If not treated in time, death from toxic shock may occur. Some patients may develop complications such as pelvic abscess, interintestinal abscess, subdiaphragmatic abscess, iliac fossa abscess, and adhesive intestinal obstruction.

　　Four, Septic shock

　　1. Septic shock, also known as septicemia shock, refers to a sepsis syndrome accompanied by shock caused by the products of microorganisms and their toxins.

　　2. Microorganisms and their toxins, cell wall products, and other substances in the focus of infection invade the blood circulation, activating various cells and humoral systems of the host;

　　3. Inducing cytokines and endogenous mediators, acting on various organs and systems of the body, affects their perfusion, leading to ischemia and hypoxia of tissue cells, metabolic disorder, dysfunction, and even multi-organ failure.

　　1, Abdominal pain

　　It is the earliest symptom to appear, and the pain is mainly caused by intestinal obstruction, the expansion of the proximal intestinal lumen, and the strong contraction of the intestinal wall. In the early stage of绞窄性肠梗阻, the pain is very acute, and some children may have shock early. Abdominal pain is accompanied by vomiting, which initially starts due to the stimulation of the peritoneum and mesentery nerves, and then due to intestinal obstruction, the reflux of intestinal contents causing repeated vomiting. High position obstruction shows vomiting early, which is green water, while low position obstruction shows vomiting later, containing feces.

　　2, Abdominal distension

　　For high position obstruction, there is only upper abdominal distension, while for low position obstruction, distension is more obvious, and intestinal loops and peristaltic waves can be seen, and the intestinal sounds are hyperactive and sound like metal or water passing through.

　　3, No defecation

　　The initial obstruction can excrete the accumulated feces at the distal end of the obstruction, and then stop defecating and passing gas. Due to frequent vomiting, a large amount of digestive fluid is lost, and because of the inability to eat and fever, the child gradually develops dehydration and acidosis. In绞窄性肠梗阻, the dehydration symptoms are severe from the beginning. A few children have widespread adhesions in the abdominal cavity, and the intestinal tract is constrained for a long time, which can lead to chronic partial simple intestinal obstruction in clinical practice, with frequent recurrence of abdominal pain and vomiting. Sometimes there is abdominal distension, which resolves spontaneously in 1-3 days. During an attack, a wide intestinal loop and peristaltic wave can be seen in the abdomen, and a complete intestinal obstruction may suddenly occur due to some factors, which is an acute attack of chronic adhesive intestinal obstruction.

　　Adhesive intestinal obstruction is a common complication of intra-abdominal surgery. How to prevent adhesion during and after surgery is an extremely important research topic. In the literature, various agents and substances have been applied, such as heparin, dicoumarol, dextran, dexamethasone, indomethacin, ibuprofen, hyaluronidase, streptokinase, silicone oil, and others, which theoretically have a preventive effect on adhesion. However, the actual effect is not certain and further research is needed. Operations should be performed carefully without damaging too much tissue. Hemostasis should be thorough to prevent the formation of hematomas and adhesions. The intestinal tract should not be exposed outside the abdominal cavity for too long, and the time for covering the organ with gauze pads should not be too long. If it is necessary to expose it for a long time, warm saline gauze should be changed in time, and the temperature should not be too high, with 35-40℃ being the most suitable. The talcum powder on the gloves must be washed clean, as talcum powder can cause adhesion in the abdominal cavity. For patients with peritonitis, the pus in the abdominal cavity should be drained as much as possible. If necessary, the abdominal cavity should be thoroughly flushed with a saline solution containing gentamicin and metronidazole. Abdominal drainage should be left in place, and the drainage tube should be removed 24-48 hours after surgery. The peritoneum and organs should be sutured flatly, and unevenly knotted lines can form adhesions. The anterior peritoneum should be sutured as much as possible, and the posterior peritoneal defect does not need to be forcibly sutured. Help the child change positions and get up early to move around. Early eating after defecation and gas passage can promote the recovery of intestinal peristalsis and can also be taken orally with domperidone. Cisapride (Prepulsid) and other gastrointestinal motility drugs can occasionally be used with neostigmine. Early postoperative application of ultra-short wave therapy can help the recovery of intestinal peristalsis and prevent or reduce intestinal adhesion obstruction.

　　1. Abdominal X-ray fluoroscopy and flat film

　　It can be seen that the small intestine is inflated with tension and liquid level, the colon is not inflated, and the barium enema shows that the colon is shrunken and gasless, which can be diagnosed as a complete mechanical small intestine obstruction. In the case of adhesive intestinal obstruction, the characteristic of the abdominal X-ray film is that the intestinal tube is not uniformly dilated, the gas and liquid levels are of different sizes, there is no range of intestinal dilation on the right abdomen, and small intestinal cavity gas shadows may occasionally appear, indicating an incomplete intestinal obstruction. When there is an abnormal dilated intestinal loop, which appears like coffee beans or in the shape of a 'C', it is the typical X-ray image of complete and strangulated intestinal obstruction. If necessary, a lateral X-ray film can be taken and compared with the standing film for observation. For incomplete intestinal obstruction, barium meal gastrointestinal fluoroscopy can also be performed to observe the site and degree of obstruction, and to make a clear diagnosis.

　　2. Abdominal ultrasound examination

　　For intestinal obstruction caused by special reasons such as cysts and tumors, B-ultrasound examination can differentiate, and experienced practitioners can detect the shape of the obstruction site and whether it is a complete obstruction.

　　It is not advisable to consume gas-producing foods such as milk, soy milk, and foods rich in rough fiber such as celery, soybean sprouts, and onions. It is forbidden to eat long-chain dietary fibers and gas-producing foods before surgery, such as celery, cabbage, rapeseed, radish, potato, sweet potato, soybeans, and broad beans. After surgery, it is forbidden to eat greasy, rough, and fishy foods such as lard, animal viscera, brown rice, dog meat, mutton, beef, and smoked fish. Rough foods should be avoided: after 3 to 4 days of surgery and after anal gas emission, it indicates that the intestinal function has begun to recover. At this time, a small amount of liquid food can be given, and after 5 to 6 days, it can be changed to low-residue semi-liquid food. It is forbidden to eat chicken, ham, pigeon meat, and soups of various vegetables. Even if this food is cooked very soft, one should not be hasty.

　　1. Treatment

　　1. Fast: Gastrointestinal decompression, inserting a duodenal drainage tube through the nose to continuously aspirate gastrointestinal secretions and inhaled gases, to reduce the pressure in the proximal intestinal tract of the obstruction, so that the compressed and twisted intestinal tract is naturally relieved with peristalsis and returns to the adhesion state before the attack.

　　2. Fluid Therapy: Correct dehydration and electrolyte disorder, and blood transfusion is necessary to improve the general condition.

　　3. Antibiotic Therapy: Eliminate infection caused by the excessive proliferation of bacteria in the intestinal tract due to intestinal obstruction.

　　4. Traditional Chinese Medicine: Traditional Chinese medicine calls intestinal obstruction 'intestine blockage'. Treatment is based on 'open the intestines and relieve constipation, promote diuresis and reduce swelling', commonly using the modified Dahuang Xiezhong Decoction. Example prescription: Dahuang 9g, Houpo 6g, Mangxiao 6g, Zhishi 9g, Laihuaizi 15g, Taoren 9g, Chishao 15g. If there is a lot of effusion in the intestinal cavity, add Gansui powder. Take 0.5-1.0g each time for oral administration.

　　5. Enema Therapy: 1% saline enema can be used, or the second decoction of the above traditional Chinese medicine can be used for retention enema to stimulate intestinal peristalsis.

　　6. Conservative Observation: Barium paste can be infused through a gastric tube to observe the shape, distribution, and degree of activity of the proximal intestinal tract of intestinal obstruction after its downward movement. Distinguish between complete and partial intestinal obstruction, and further observe the location of the obstruction at the distal end, which is beneficial for choosing the surgical incision if necessary.

　　2. Surgical Treatment

　　Patients under conservative observation and treatment should be transferred to surgery if they have the following indications:

　　1. Symptoms of poisoning become severe, pulse and respiration increase, body temperature rises, dehydration cannot be corrected or is unstable.

　　2. Abdominal distension worsens, abdominal muscles appear tense and painful, and there is progression in conservative observation.

　　3. Abdominal puncture, microscopic examination of abdominal effusion has pus cells or red blood cells.

　　4. After taking barium, the barium cannot move downward, or it remains fixed in one place for a long time. The specific surgical method is determined according to the specific situation of the child at that time and the pathological changes, and can be performed as simple adhesion separation, intestinal resection and anastomosis, or external stoma, and II stage anastomosis.

　　3. Prognosis

　　Prognosis is closely related to early diagnosis and early treatment. Generally, simple intestinal obstruction patients have good surgical treatment effects after correcting dehydration and acidosis. However, strangulated intestinal obstruction depends on the extent of necrotic intestinal tract. Generally, timely rescue can save lives. If there is a short small intestine (remaining small intestine less than 40cm) after the injury, the prognosis is poor.