Colonic atresia
Introduction
Introduction to colonic atresia The incidence of colon atresia is 1 in 1500 to 20,000, and less than 5% occur in colons in all cases of intestinal atresia. The etiology and pathology are basically the same as the small intestine atresia. Types are: 1 diaphragm composed of mucosa and submucosa, more common in the ascending colon and sigmoid colon. 2 Both ends are blind ends with connective tissue in the middle. 3 There is no connective tissue between the two blind ends, which is more common in the transverse colon. basic knowledge Sickness ratio: 0.0001% Susceptible population: newborn Mode of infection: non-infectious Complications: constipation
Cause
Cause of colonic atresia
Congenital malformation of the intestine is one of the common causes of intestinal obstruction in the neonatal period.
Causes
1. Intestinal cavitation in the embryonic period
According to Tandie's theory, it is believed that before the fifth week of embryonic development, the digestive lumen has a complete intestinal tube covered by epithelial cells. After that, the epithelial cells grew extremely fast, and the intestinal lumen was occluded due to the proliferation of epithelial cells, which was called the parenchymal phase. Later, vacuoles appeared in the middle, forming cystic spaces and merging with each other. At 12 weeks of embryonic re-opening of the intestine, if the gaps were incomplete, the formation of occlusion or stenosis. In recent years, some questions have been raised about this theory. For example, type III small intestine or colon atresia cannot be explained by Tandler's theory.
2. The fetal mesenteric blood circulation is impaired due to damage
Intestinal vascular branch malformation or occlusion, fetal intra-abdominal infections such as fecal peritonitis can lead to colonic atresia and stenosis. Louw et al. conducted a study on the cause of colonic atresia. In 1955, a fetal dog was used for the test. They ligated a small mesenteric blood vessel in the litter, which can cause this small intestine atresia, and this segment of the small mesentery is also defective. It is suggested that the gastrointestinal atresia is caused by obstruction after the embryonic mesenteric injury. The cause of the injury may be the intestine. Torsion, poor intestinal rotation, internal hemorrhoids or vascular malformations.
Abram et al (1968) used 80 days of sheep fetus to test the tear of the mesentery of the sheep, almost 100% can cause type I, II or III intestinal atresia, so the colonic atresia and stenosis may occur during embryonic development. Any one of them exists.
Pathogenesis
1. Pathology: pathology and small intestine atresia are very similar, depending on the degree and shape of the atresia, can be type 3:
Type I diaphragm atresia: Membrane septum in the intestinal lumen, membranous septum colonic cavity is divided into the far and near side, the two parts are not connected to each other; or a small hole in the center of the diaphragm communicates to form a colonic stenosis.
Type II cord-like atresia: the mesentery is intact, the distal end of the intestine, and the blind end of the proximal end are connected by a fiber cord.
Type III mesenteric defect: the distal end of the intestine is the blind end of the separation. The mesentery also has a V-shaped defect.
Intestinal atresia and stenosis occurring in ascending and transverse colons are mostly type III, and intestinal atresia and stenosis occurring far beyond the splenic curvature are more common in type I and II.
The proximal tubule of the atresia is obviously dilated, hypertrophic, and the peristaltic function is poor. The distal intestine is collapsed, shrunk and thinned, and there is a white hard mucus substance in the intestinal lumen. If the ileocecal valve is intact and the atresia is located far beyond the colonic hepatic curvature, a blind sputum is formed, and the blind sacral intestine between the ileocecal valve and the atresia is highly dilated, and the intestinal wall is thin, ischemic, necrotic, and even perforated. Because part of the intestinal atresia and stenosis occurs in the third trimester of pregnancy, about 10% to 20% of children with colonic atresia can expel fetuses soon after birth.
2. Combined malformation: colonic atresia is often accompanied by skeletal deformities such as phalanges, multiple fingers and clubfoot, ocular and cardiovascular malformations; abdominal wall, umbilical bulge and other abdominal wall deformities, congenital megacolon, duodenum And small intestine atresia.
Prevention
Colonic atresia prevention
Maintain local cleanliness after surgery to prevent anal stenosis caused by various infections. Main preventive measures:
1, early pregnancy, avoid fever and cold. Women who have had high fever in early pregnancy, even if the child does not have obvious appearance deformity, brain tissue development may be adversely affected, manifested as mental retardation, poor learning and reaction ability, this mental retardation can not be restored. Of course, fetal fever caused by high fever is also related to the sensitivity of pregnant women to high fever and other factors.
2. Avoid getting close to dogs and cats. Few people know that cats with bacteria are also a source of infectious diseases that are a great threat to fetal malformation, and cat feces are the main route of transmission of this malignant infectious disease.
3. Avoid women who wear makeup every day. According to the survey, the incidence of fetal malformations in heavy makeup is 1.25 times less than that of heavy makeup. The main adverse effects on fetal malformation are arsenic, lead, mercury and other toxic substances contained in cosmetics, which affect the normal development of the fetus. Secondly, some of the ingredients in the cosmetics are exposed to ultraviolet rays in the sun to produce teratogenic aromatic amine compounds.
4, to avoid mental stress during pregnancy. Human emotions are controlled by the central nervous system and the endocrine system. One of the endocrine corticosteroids is closely related to human mood changes. When pregnant women are emotionally stressed, adrenocortical hormone may block the fusion of a certain tissue of the embryo. If it occurs during the first 3 months of pregnancy, it will cause malformations such as cleft lip or palate.
5. Avoid drinking alcohol. Pregnant women drink alcohol, alcohol can enter the developmental embryo through the placenta, causing serious damage to the fetus. Such as a small head, very small ear and nose and a wide upper lip.
6, avoid eating mold and vegetarian food. Experts pointed out that if pregnant women eat food contaminated with mycotoxin (mildew food), mycotoxins can cause fetal chromosome breaks in the fetus through the placenta.
Complication
Colonic atresia Complications constipation
Frequent constipation can occur concurrently, even the fecal impaction of long-term defecation is not smooth, can cause the proximal straight colon to gradually expand, leading to secondary giant straight colon disease.
Symptom
Colonic atresia symptoms Common symptoms The formation of hard fecal stone in the colon, lower abdominal pain, intestinal atresia, bloating
As a typical low intestinal obstruction, abdominal distension is obvious, the vomit is fecal-like, no meconium is discharged, the abdominal plain film sees the intestines inflated and multiple liquid levels on the whole abdomen, and the lock enema can indicate the locked part, which helps to determine diagnosis.
Examine
Examination of colonic atresia
(1) fiber colonoscopy: can directly examine the rectum, colon, cecum, ileocecal valve and ileum, can also do biopsy, cancer screening, polypectomy and cauterization, is conducive to early diagnosis of colon disease.
(2) CT scan examination: it is a sensitive method for examining anorectal cancer. It can be found in the front of the sputum, the side wall of the basin, the pelvic organs and the lymph nodes, to determine the size of the cancer, the intestinal wall, the fat around the rectum, the uterus and muscles. Preoperative and postoperative scans can help develop treatment options for surgical radiotherapy.
(3) MRI examination: preoperative examination and recurrence examination of rectal cancer can be performed to determine the extent of residual cancer after radiotherapy, and the rectal and anal stenosis and its degree of disease can be diagnosed.
Diagnosis
Diagnosis of colonic atresia
Can be diagnosed based on clinical performance and laboratory tests.
Rectal cancer: early rectal cancer is asymptomatic, occasionally history of bloody stools, so it is difficult to find that the formation of colonic atresia has been advanced to the advanced stage, the position of the lower position can be touched, the tumor is irregular, uneven, hard, tender, refers to Sputum blood staining, higher position, should be sigmoidoscopy or fiberoptic examination, endoscopically seen rectal mass intestinal mucosa is more complete, biopsy can be diagnosed, rectal cancer low anastomosis or other anal stenosis must be done Multiple biopsy to rule out the possibility of local recurrence.
