Small intestine rupture

　　1. Etiology

　　Small intestine injury is caused by direct and indirect violence, mainly seen in abdominal blunt trauma, small intestine rupture caused by falling from a height or sudden deceleration. It is generally believed that the rupture occurs frequently in the proximal jejunum within 50cm of the Treitz ligament and in the distal ileum within 50cm of the ileocecal junction. Traumatic damage can generally be divided into closed intestinal injury, open intestinal injury, and iatrogenic intestinal injury.

　　1. Closed intestinal injuries can be divided into 4 types based on the different principles of violence action.

　　(1) Injury caused by direct violence: The lumbar sacral physiological curvature is closer to the abdominal wall than other vertebrae. Direct violence acts on the abdominal wall and transmits to the lumbar sacral region, causing injury to the small intestine or mesentery. Under the direct action of strong external force, the intestines are compressed between the abdominal wall and the spine or sacral promontory, causing contusions and lacerations of the small intestine, and in severe cases, can directly cut the small intestine. Injuries from the midline around the umbilicus often affect the jejunum and ileum, sometimes with rupture, contusion, or bleeding of the mesentery. External force slightly off the body axis can also be associated with injury to the liver, spleen, kidneys, and colon. When the abdomen is subjected to a large area of violence, it can cause the duodenojejunal flexure and the lower segment of the ileum to close simultaneously, forming a closed loop in the upper segment of the jejunum, causing a sudden increase in intraluminal pressure and leading to rupture. This type of injury often occurs after a meal, and the rupture and perforation often occur in the lateral wall of the small intestine away from the site of violence, where the intestinal contents are filled.

　　(2) Injury caused by lateral violence: External force can also act on the abdomen in a direction斜切 along the body axis, causing the intestines and mesentery to move rapidly to one side. When the range of movement exceeds the bearing capacity of the fixed intestinal mesentery or ligaments, it may cause the intestines to tear from the attachment point. The common sites of injury are near the beginning of the jejunum close to the Treitz ligament or the distal ileum fixed by the peritoneum. Similarly, this type of injury can also occur in abdominal inflammatory lesions, abdominal surgery, or after intraperitoneal medication, which causes pathologic adhesions in the abdominal cavity. The lateral violence can also cause a sudden increase in pressure within a segment of the intestinal tube. The already distended and inflated intestinal tube does not have time to disperse the external force or to find room for rotation between the curved and full loops. When the fluid pressure within the intestinal lumen increases sharply, it can cause the intestines to burst or have a small perforation at the oblique insertion site of the mesenteric blood vessels on the lateral wall of the intestines away from the site of external force. This injury is generally 0.5 cm in diameter, and the surrounding intestinal wall and mesentery are normal. This type of injury is easily overlooked during exploration.

　　(3) Injury caused by indirect violence: This often occurs under the mechanism of force against the inertia of the intestinal movement. When a patient falls from a height, sustains a fall, or suddenly stops, the intestines or mesentery cannot withstand the pressure from the sudden change in position. This pressure is transmitted, causing the small intestine to break or tear. This type of injury often occurs at the fixed ends of the small intestine, such as near the ends of the jejunum and ileum attached to the posterior abdominal wall and the site of the greatest mobility of the jejunum and ileum junction. It is more common in the small intestine that contains a large amount of chyme and is in a full state.

　　(4) Severe injury caused by strong muscular contraction: Improper force can cause the body to tilt backward abruptly, leading to strong contraction of the abdominal muscles. The increased intra-abdominal pressure can lead to tears in the small intestine or mesentery. In some cases, it is the contraction of the abdominal muscles against the normal movement of the intestines that causes the injury. It is relatively rare for strong contraction of the abdominal muscles to cause a rupture of the small intestine. The General Hospital of Tianjin Medical University once treated a 76-year-old male patient. He developed abdominal pain and peritoneal irritation gradually after lifting heavy objects with both hands in collaboration with others. The surgery confirmed that there was a 0.5 cm rupture of the ileum 150 cm from the ileocecal junction, with the mucosa inverted outward.

　　13. Open intestinal injury

　　Primarily caused by sharp objects, such as bullet, shrapnel, or ball injuries, and sharp instrument injuries. Open small intestinal injury must have foreign bodies entering or passing through the abdominal cavity, which may be a single wound injury or multiple wound injuries, and the damaged intestinal tract may be far from the wound site. It often causes multiple intestinal perforations or complex injuries.

　　3. Iatrogenic intestinal injury

　　Intestinal injuries in medical practice also occur occasionally. Common causes include accidental injury to the intestinal tract during surgical separation of adhesions, piercing of distended or highly distended intestinal tract during abdominal puncture, unexpected injury during endoscopic procedures, and accidental injury to the small intestine during induced abortion, leading to intestinal perforation or rupture. There are also cases where the blood vessels of the jejunum and ileum are damaged, forming a hematoma.

　　2. Pathogenesis

　　The pathological changes of small intestinal injury depend on the degree and location of force applied to the small intestine, as well as the presence of associated injuries.

　　1. Closed intestinal injury

　　The pathological manifestations of closed intestinal injury include contusion of the intestinal wall, hematoma, and rupture. In cases of mild contusion of the intestinal wall, the injured intestinal tube only has local congestion and edema, and the continuity of the intestinal wall tissue is not destroyed, with sufficient blood supply that can heal spontaneously. Severe contusion can cause the injured intestinal mucosa to lose its integrity, with the range of local ischemia exceeding the compensation of collateral circulation, eventually leading to ulcers, necrosis of the intestinal wall, perforation, and the entry of intestinal contents and bacteria into the abdominal cavity, causing peritonitis. The healed intestinal wall may also form scar-like stenosis of the intestinal tract.

　　The pathological changes after intestinal wall laceration vary with the depth and extent of the injury. For simple mucosal lacerations without damage to the muscular layer and small simple serosal layer lacerations, the body's own repair ability can heal the injury without obvious clinical symptoms or sequelae. Lacerations that damage the muscularis mucosa can have obvious bleeding and inflammatory changes, and even intestinal rupture can occur at the site of injury. If mucosal lacerations involve submucosal blood vessels, infection and intestinal perforation can occur on the basis of local bleeding. Therefore, for severe intestinal wall lacerations, although no serious complications have appeared early, it is still necessary to emphasize the主动性 of treatment to prevent potential hidden dangers.

　　The jejunum is relatively free in the abdominal cavity compared to other organs, so the opportunity for vascular injury and hematoma is relatively low. However, the intestinal tubes in the upper part of the jejunum and the distal part of the ileum are relatively fixed, with short mesentery and lack of buffering capacity. They can be damaged by external force, leading to injury of superior mesenteric artery or vein or inferior mesenteric artery or vein and their branch vessels, forming a hematoma, which poses a serious threat to the intestinal wall. A small amount of continuous bleeding can spread along the intestinal space and develop into a larger hematoma, affecting the blood supply of the intestinal tract. The hematoma can break through the serosa or mucosa to a certain extent, and in severe cases, it can lead to hemorrhagic shock or death. Secondary intestinal ulcers, perforations, peritoneal abscesses, and peritonitis can occur on the basis of a hematoma.

　　13. Open intestinal injury

　　The characteristics of open intestinal injury are that the abdominal wall and intestinal tract are injured simultaneously, and sometimes intestinal contents can be seen to flow out through the abdominal wall wound. When dealing with abdominal foreign bodies, attention must be paid to finding the entrance and exit of the foreign body relative to the intestinal wall, and most wounds are opposed. The bullet trajectory of gunshot wounds can travel a certain distance in the intestinal cavity, causing the distance between the two rupture holes on the intestinal surface to be far apart. Large shrapnel injuries are localized, and steel shot bullets may cause up to dozens of intestinal tract injuries, with small rupture holes and widespread distribution, which are easy to miss. When the trajectory of the injury is tangential to the intestinal tract, the penetrant happens to stay in the intestinal cavity, or the force of the injury does not reach the other side of the intestinal wall, there may be only one rupture hole.

　　The pathological changes of open small bowel injury are mainly peritonitis. Small perforations have only a small amount of intestinal content entering the abdominal cavity, and besides local peritonitis, there are no other symptoms. When the small bowel injury and rupture are large, or the time of hospitalization is slightly late, gastrointestinal contents or gas may be discharged through the abdominal wall open wound, and in more severe injuries, blood or damaged intestinal tract, omentum, and other tissues may be discharged through the abdominal wall wound.

　　8. Peritonitis is a common severe surgical disease caused by bacterial infection, chemical irritation, or injury. Most cases are secondary peritonitis, originating from organ infection in the abdominal cavity, such as necrosis and perforation, trauma, and others. The main clinical manifestations are abdominal pain, abdominal muscle tension, nausea, vomiting, fever, and in severe cases, blood pressure drop and systemic toxic reactions. If not treated in time, death may occur due to toxic shock. Some patients may develop complications such as pelvic abscess, interloop abscess, subdiaphragmatic abscess, iliac fossa abscess, and adhesive intestinal obstruction.

　　7. Shock (shock) is a clinical syndrome characterized by acute effective blood volume deficiency caused by various severe pathogenic factors, with clinical features of neuro-humoral factor disorder and acute circulatory disorder. These pathogenic factors include massive hemorrhage, trauma, poisoning, burns, asphyxia, infection, allergy, heart pump function failure, and others.

　　6. Poisoning refers to the occurrence of disease or death in individuals who have excessive or massive exposure to chemical toxins, leading to tissue and functional damage, metabolic disorders, and disease or death.

　　1. Abdominal pain, abdominal distension, and fever.

　　2. Abdominal muscle tension, diffuse abdominal tenderness and rebound pain, mobile dullness (+), and decreased or absent bowel sounds.

　　3. Severe cases may be accompanied by shock: mild excitement signs appear in the presence of primary symptoms and signs, such as clear consciousness, but restlessness and anxiety, mental tension, pale complexion and skin, mild cyanosis of the lips and nail beds, increased heart rate, increased respiratory rate, cold sweat, thin and rapid pulse, sudden drop in blood pressure, slight drop, or even normal or slightly high, reduced pulse pressure, and decreased urine output.

　　1. After diagnosis is confirmed, surgery should be performed immediately. If intraperitoneal hemorrhage is found, the solid organs and mesenteric blood vessels should be explored first to find the bleeding focus, and appropriate treatment should be given. Then, the bowel should be explored starting from the Treitz ligament and checking segment by segment. Small perforations at the mesenteric margin are sometimes difficult to find, and the beginning and end of the small bowel, adhesed bowel segments, and bowel loops entering the hernial sac are prone to injury, so special attention should be paid. The perforation site can be clamped gently first to prevent the contents of the bowel from continuing to溢出, and then according to the findings, appropriate treatment can be given after completing the exploration of the entire small bowel.

　　2. The treatment of small bowel injury depends on its degree and extent. Fresh perforations or linear fissures at the edge of the wound can be sutured and repaired. Large defects in the bowel wall, severe contusions leading to loss of vitality of the bowel wall, or multiple perforations in a bowel segment should undergo partial resection and anastomosis of the small bowel.

　　3. Mesenteric contusion and laceration, often leading to severe hemorrhage or hematoma formation. Treatment includes proper hemostasis, resection of bowel segments with poor blood circulation caused by this, and repairing the mesenteric rupture to prevent internal hernia. There is occasionally injury to the main trunk of the mesenteric artery, which requires vascular repair or anastomosis and other reconstruction procedures, and it should be avoided to widely resect the small bowel to avoid short bowel syndrome. The collateral circulation of the mesenteric veins is relatively rich, and generally, although the ligation of larger veins does not lead to circulatory disorders, caution should still be exercised.

　　Before surgery, the main basis for clear examination and diagnosis includes:

　　1. There is a direct or indirect violent injury history, the main affected site is mainly located in the abdomen;

　　2. There is spontaneous abdominal pain that persists;

　　3. The location of abdominal pain is fixed or the range gradually expands;

　　4. There are signs of peritoneal irritation;

　　5. Follow-up shows worsening abdominal symptoms but no signs of internal hemorrhage;

　　6. There are signs of free peritoneal gas;

　　7. Localized small bowel air-liquid level;

　　8. Ultrasound shows local liquid shadow areas or gas echoes in the free abdominal cavity;

　　9. Puncture of the abdomen has ascites;

　　10. There is an infection toxic shock.

　　In order to improve the early diagnosis rate, the following points should be paid attention to in the diagnostic process:

　　1. Detailed inquiry and physical examination: such as the location of injury, the size and direction of external force, the patient's reaction after injury; a comprehensive and detailed physical examination should be carried out, and the pain point, range, changes in liver dullness, whether there is mobile dullness, and changes in bowel sounds should be checked one by one.

　　2. Close observation: For those who cannot be diagnosed immediately, pay special attention to the first impression, dynamic observation, and repeated comparisons. The observation period should generally be in the hospital, and anesthetic painkillers should not be used; for patients with multiple injuries, due to the complexity and severity of the condition, attention is often only paid to obvious injuries outside the abdomen, such as fractures, cranial and brain injuries, or shock and coma, which may conceal the symptoms of abdominal injury. Such patients should be treated for other associated injuries while actively treating shock and closely observing changes in abdominal signs. The clinical manifestations of small bowel injury depend on the degree of injury, the time of injury, and whether there are injuries to other organs.

　　Patients should gradually return to normal diet after surgery, pay attention to eat less and more meals, eat 5-8 times a day, 50-100 grams each time, from liquid food, semi-liquid food to soft food, and transition to normal diet requires 3-6 months. Diet should be light, rich in vitamins and proteins, easy to digest, such as eggs, dairy products and their products, lean meat, tofu, soy milk, fresh vegetables and ripe fruits, etc. At the same time, patients should develop the habit of eating slowly, being patient in chewing and masticating, using the tongue to help with saliva to mix, and replacing part of the digestive function of the stomach with the mouth. In addition, in daily life, it is necessary to limit the intake of fried, spicy, too sweet, too hot, and irritating foods, especially avoiding indigestible and too sticky foods such as dumplings, sticky rice cakes, cold rice cakes, and sticky bean dumplings. After surgery, the reduction of gastric acid often affects the absorption of iron, so it is appropriate to supplement some iron preparations to avoid iron deficiency anemia.

　　First, treatment principles

　　1. Prevention and treatment of shock.

　　2. Anti-infection.

　　3. Correction of water and electrolyte disorders.

　　4. Surgical treatment.

　　Second, medication principles

　　1. For those with simple intestinal perforation and good general condition, postoperative treatment should mainly include drug fluid replacement, anti-infection, and correction of water and electrolyte disorders.

　　2. For those with shock, active anti-shock treatment should be given.

　　3. For elderly patients with severe damage and poor nutritional status, postoperative support therapy should be strengthened, and blood transfusion or human serum albumin should be given when necessary to enhance the healing ability of the wound.

　　Once the diagnosis of small bowel rupture is confirmed, surgical treatment should be carried out immediately. The surgical method is mainly simple repair. Generally, intermittent transverse suture is adopted to prevent the occurrence of stenosis in the intestinal lumen after repair.

　　4. Partial small bowel resection and anastomosis should be adopted in the following situations:

　　(1) Those with large or severe lacerations or serious bruising of the intestinal wall tissue at the edge of the laceration;

　　(2) Those with multiple ruptures in a small segment of the intestinal tract;

　　(3) Those with most or all of the intestinal tract broken;

　　(4) Those with mesenteric injury affecting intestinal blood circulation.