What Causes Colon Strictures?

Intestinal atresia and intestinal stenosis are common congenital gastrointestinal malformations in neonatal intestinal obstruction, which can occur in any part of the intestine, with the jejunum and ileum being the most common, followed by the duodenum and the colon being rare.

Intestinal stenosis

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Intestinal atresia and intestinal stenosis are common congenital gastrointestinal malformations in neonatal intestinal obstruction, which can occur in any part of the intestine.

1. Duodenal atresia and stenosis At the 5th week of the embryo, the intestinal epithelial cells proliferate excessively and occlude the intestinal cavity, and a temporary filling period appears. By the 9th to 11th weeks, the filled epithelial cells undergo cavitation. And many vacuoles appeared, and later the vacuoles re-fused to make the intestinal cavity penetrate again, and a normal intestine was formed at the 12th week. If the intestinal tube is re-luminalized and obstructed, it can form atresia or stenosis, which is the main cause of duodenal atresia (Tandler theory). And often accompanied by other deformities, such as congenital dysfunction, intestinal malrotation, circular pancreas, esophageal atresia, and anorectal, cardiovascular and urinary tract deformities. Multi-system malformations coexist, suggesting that this is related to systemic developmental defects in the early stage of the embryo, rather than simply duodenal local dysplasia.

2, empty, ileum atresia and stenosis: In recent years it is believed to be caused by intestinal blood circulation disorders. During the fetal period, after the intestine has formed, some abnormal pathological changes in the intestine, such as intestinal torsion,

1. Duodenal atresia and stenosis: It usually occurs in the second part of the duodenum, most of which are at the distal end of the ampulla and a few are at the proximal end. Common types are: diaphragm type: the shape of the intestinal canal is continuous, and there is an unbroken diaphragm in the intestinal cavity, which can be single or multiple; or the diaphragm is prolapsed to the distal end of the obstruction site in a web shape. Air bag-like changes; or a small hole in the center of the diaphragm communicating. Blind segment type: the continuity of the intestine is interrupted, the two blind ends are completely separated or only the fiber cable is connected, and the mesentery also has a wedge-shaped defect. This type is rare. Duodenal stenosis: the mucosal ring hyperplasia in the intestine, where the intestinal wall does not have the function of expansion, but also shows a constricted intestinal segment near the ampulla. Obvious dilatation of the duodenum and stomach near the obstruction, hypertrophy of the intestinal wall, degeneration of the plexus between the intestinal walls, small intestinal atrophy during intestinal atresia, thin intestinal wall, no gas in the intestinal cavity, and intestinal distant intestinal Gas may be present in the cavity.

2. Jejunum ileum atresia and stenosis: The full length of the normal small intestine is 250-300cm for mature children and 160-240cm for immature children. Intestinal atresia was significantly shorter than normal, only 100-150cm, or even shorter. The closed proximal intestinal cavity is extremely dilated due to the accumulation of contents, with a diameter of up to 3 to 4 cm, intestinal wall hypertrophy, poor peristaltic function, poor blood flow and even necrosis, perforation. The distal intestinal canal was small and collapsed, with a diameter of less than 4-6 mm, no gas in the cavity, and only a small amount of mucus and exfoliated cells. May be combined with meconium peritonitis. Accompanying malformations include intestinal malrotation, intestinal torsion, abdominal fissure, rectal and anal atresia, congenital heart disease, and congenital fool type.

Prognosis is related to birth weight, atresia site and type, and associated malformations and infections. Common causes of death are pneumonia,

3. Postoperative management

(1) General treatment: The sick child should be placed in an incubator after operation to maintain a stable temperature and humidity, and oxygen should be cut off when necessary.

(2) Gastrointestinal decompression: keep the gastrointestinal decompression unobstructed and reduce the abdominal distension of sick children.

(3) Nutrition support: daily fast water, electrolytes and intravenous high-nutrition fluids during fasting. Usually 7 to 14 days after the operation, the intestinal function can only be eaten by mouth. Starting at 5-10ml each time, once every 2 hours. If the sick child does not vomit, the feeding amount can be gradually increased. Normally, normal feeding can be resumed after 4-5 days after the start of feeding. Apple-Peel atresia and multiple atresia require long-term intravenous intubation of TPN. During TPN, the blood image, blood biochemistry, blood gas analysis, liver and kidney function, jaundice, and venous catheter complications were closely observed, and reasonable prevention and treatment was given.

(4) Anti-infection: Vitamin B, C, K and antibiotics are given within a few days after the operation, and whole blood, plasma or albumin is intermittently transfused to prevent incision infection and ensure good healing.

(5) Promote the recovery of intestinal function: 7 days after the operation, 10 to 15 ml of warm saline can be used for enema, 2 to 3 times / d.

4. Common postoperative complications and management

(1) Anastomotic obstruction: the most common complications after operation, including functional and mechanical obstruction.

Reason:

A. Functional obstruction:

a. Proximal dysfunction of the proximal bowel is poor. Due to the persistently increased pressure in the closed proximal bowel cavity and the expansion of the bowel, the muscle layer of the bowel wall is hypertrophic, and the peristalsis function is poor or disappears. Before the intestinal anastomosis, the section of the intestine is not removed or the resection is incomplete, which affects the anastomotic passage function.

b. Distal intestinal hypoplasia: After the fetus develops intestinal atresia, the distal intestinal cavity is left empty for a long time, intestinal hypoplasia, and no peristalsis of the intestinal wall. The recovery of distal bowel function after intestinal resection and anastomosis requires a certain time, so temporary anastomotic obstruction occurs.

c. The occlusion site and adjacent intestinal myenteric ganglion cells are reduced. Intestinal atresia due to inflammation or blood supply disorders can cause intestinal plexus and ganglion cell developmental disorders or degeneration, resulting in anastomotic functional obstruction.

B. Mechanical obstruction:

a poor anastomosis technique: common causes of anastomotic obstruction, such as disproportion of the intestinal canal diameter at the distal and near ends, excessive folding of the proximal intestinal wall during anastomosis, or excessively large needle incision margin during suture, and excessive inversion tissue; The diameter of the distal intestine is less than 1cm, and double-layer anastomosis is used to anastomize the intestine, which causes anastomosis or obstruction.

b. Postoperative intestinal adhesions, which cause the bowel near the anastomosis to distort or fold, making the anastomosis an angular obstruction.

Clinical manifestations and treatment of anastomotic obstruction: Patients with gastrointestinal decompression fluid are still bile after 1 week of surgery, or when abdominal distension, vomiting, and normal defecation occur repeatedly after gastric tube removal, the possibility of anastomotic obstruction should be considered. An appropriate amount of lipiodol can be injected through the gastric tube for angiography to understand the anastomotic passage. If it is determined that there is a mechanical obstruction of the anastomosis, the operation should be repeated to remove the cause of the obstruction, and the diseased bowel segment and the original anastomosis should be re-synthesized. Functional obstruction is often related to the reduction of the number of intermuscular ganglion cells in the distal and proximal intestinal canals, and insufficiency of the distal intestine. In this case, you should continue TPN and pay attention to multivitamins and trace elements. Patient feeding, first give a small amount of diet or breast milk. As the bowel continues to develop, the peristaltic function is expected to recover. This process usually takes 2 to 3 weeks.

(2) Anastomotic leak

Reason:

A. Systemic factors: advanced cases with water, electrolyte disorders, hypoproteinemia, vitamin deficiency or jaundice, etc., affect the formation of anastomotic collagen fibers and tissue healing.

B. Local factors:

a. Incorrect surgical technique: the most important cause of anastomotic leakage. The anastomosis technique is not good, such as thick sutures, sparse or too dense sutures; when the anastomosis is double sutured, or when the mucosa or sutures are missed, the needle passes through the entire intestinal wall; when the anastomosis is opposite Poor cohesion, eversion of the mucosa; erroneous piercing or cutting of the mesenteric blood vessels, which damages the anastomotic intestinal blood flow; use hard forceps to clamp the intestinal wall and mesentery, contusing the intestinal tissue and mesangial blood vessels, affecting the anastomotic blood flow.

b. Proximal dilated intestinal tube resection is not enough: to keep the intestinal tube with hypertrophy, edema and poor blood flow, and make the anastomosis heal poorly.

c. Anastomosis at the distal end of anastomosis: such as multiple atresias, leakage or distortion of the distal intestine, blockage of dry feces in the distal intestinal cavity, etc., resulting in obstacles to the passage of proximal intestinal contents, increased pressure in the intestinal cavity, and anastomosis. Cracked or leaking.

Clinical manifestations: Anastomotic leakage in neonates is not easy to diagnose. The missed time is mostly 3 to 7 days after surgery. In the case of continuous gastrointestinal decompression after pediatric surgery, anastomotic leakage often behaves like intestinal paralysis, such as abdominal distension, abdominal tenderness, elevated body temperature, left shift of blood image, and poor bowel movements. Clinicians often mistakenly believe that it is intestinal paralysis or Postoperative response. Sometimes there is a small amount of free gas in the abdominal X-ray film, which is also easily confused with postoperative pneumoperitoneum. The diagnosis was confirmed until the abdominal incision overflowed with fecal juice or intestinal fluid. Therefore, anastomosis may be considered when the above symptoms occur after surgery. Carefully observe the condition and physical examination. If the symptoms and signs do not improve, repeat abdominal X-rays or abdominal B-ultrasound, abdominal puncture, etc. to assist diagnosis.

Treatment: In the early stage of anastomotic leakage, the intra-abdominal infection is serious. Excessive surgical exploration should be avoided, and complicated intestinal resection and anastomosis or repair should not be performed. After grasping the situation of anastomotic leakage, local dilatation and drainage were performed, and the double-lumen tube was left to attract. According to the nature and amount of drainage fluid every day, do a good job of fluid and electrolyte supplements, correct acid-base poisoning. Give parenteral nutrition to provide sufficient calories and nutrition. Strengthen antibiotic treatment to effectively control infection and care of abdominal skin. Under active treatment, children are allowed to go through the acute phase and undergo further surgical treatment after entering the stable phase. Confined ileum or anastomotic skin fistula can be treated with conservative therapies to maintain water and electrolyte balance, strengthen nutritional support therapies, control infections, and protect the skin of the abdomen. If the condition is stable and can defecate or breast milk more than normal, a smaller anastomotic leak is expected to heal on its own.

(3) Necrotizing enterocolitis:

Reason: Small intestine atresia Original congenital defect of intestinal blood supply, especially Apple-Peel type atresia, small intestine nutrition only relies on retrograde blood supply of right colon artery, any factors affecting blood circulation, such as dehydration, can make intestinal blood Stream reduction. Poor microcirculation perfusion triggers the occurrence of necrotizing enterocolitis. Lesions can affect the small intestine and colon.

Clinical manifestations: abdominal distension, vomiting, fever, diarrhea, or blood in the stool, and severe systemic poisoning. Abdominal X-ray film showed obvious flatulence and flatness of the small intestine and colon, obvious uneven distribution of flatulence in the small intestine, and widening of the small intestine space.

treatment: small intestine wall gas can be diagnosed. Mild patients actively treat toxic shock, correct dehydration and acid-base balance disorders, gastrointestinal decompression and effective antibiotics. Those who have intestinal obstruction or perforation of intestinal necrosis should be treated surgically. Intestinal resection and anastomosis, or external intestinal or intestinal fistula according to the condition.

(4) Short bowel syndrome: can occur in multiple small bowel atresia or Apple-Peel atresia complicated by bowel torsion intestinal necrosis. Due to shortened time of food passing through the small intestine, or changes in osmotic pressure of intestinal contents caused by lactose and other compound absorption disorders, diarrhea and nutritional disorders can occur in sick children, low body weight, hyponatremia, hypokalemia, and developmental delay. In terms of treatment, the life of sick children should be maintained with TPN at an early stage. After the small intestine adaptability is improved, medical treatment is mainly given, and low-fat, high-carb hydrate foods are given, and vitamins and trace elements are actively supplemented.

What causes intestinal stenosis

1.Congenital malformation

It is generally believed that the anorectal insufficiency during the embryonic developmental stage, anorectal membrane development between the rectum and the anal canal is abnormal, the membrane is incompletely perforated or not disappeared after birth, anorectal stenosis or even atresia. After birth, anal atresia is not properly handled, often narrowed. There are also deformities of the zygomatic coccyx that oppress the intestinal cavity.

2.Inflammation

Such as ulcerative colorectitis, Crohn's disease, STD lymphogranuloma, intestinal tuberculosis, chronic dysentery, perianal abscess, complex anal fistula, amoebic bowel disease, schistosomiasis bowel disease, etc., can make anal canal connective tissue hyperplasia Hypertrophy, the formation of scars, the intestinal tube loses elasticity and narrows the lumen.

3. Damage

One of the common clinical causes is improper surgical treatment, such as excessive resection of internal hemorrhoid mucosa and excessive resection of external hemorrhoid skin. Such as internal hemorrhoids or rectal prolapse sclerosing agent or necrotic agent injection is too large or concentrated in a plane, or external hemorrhoid injection volume is too large. Chen Kai et al. Have reported a group of iatrogenic anorectal strictures, of which 46.37% were caused by injection therapy. Or use corrosive drugs such as dry hemorrhoid therapy, "compressed Dan" and other injuries to the anorectal rectum, or improper rectal anastomosis, etc., can make the intestine form scar contracture and narrow, which is the most common clinical cause of anorectal stenosis; The second is accidental injury, such as anorectal stab wound, the most common is scar formation due to fall injury, foreign body injury, etc .; the third is physical and chemical injury, common burns, scalds, strong acid, strong alkali damage, radiotherapy and so on.

4, mass compression

Tumors in the anus, anal canal, and rectum occupy or compress the lumen, such as anorectal tumors, giant rectal polyps, etc., as well as compression of tumors in adjacent organs, such as vagina, uterine tumors, prostate tumors, larger lymphomas, smooth muscles Tumors, chordomas, anterior sacral meninges, and zygomatic coccygeal deformities can cause anal or rectal strictures.

5, muscle cramps

Common causes include functional sphincter spasm caused by internal sphincter spasm, puborectalis spasm, and pelvic floor muscle group spasm, also known as pseudostenosis. Hypertrophy of the puborectalis can cause true stenosis.