Congenital short colon

　　One, etiology

　　Chadha et al. believe that the regional incidence of congenital short colon varies, which may be related to racial, dietary, or environmental factors. Since these cases are sporadic, there is no evidence of familial inheritance.

　　Stephens (1983) believes that at 4 to 6 weeks of human embryo development (4 to 16mm in length), the cloaca is separated by the descending urorectal septum or cloacal septum, and the cloaca is divided into two parts: the anterior part is the urogenital sinus, and the posterior part is the rectum. At the same time, the distal cloacal membrane is also divided into two parts: the anterior part is the urogenital membrane, and the posterior part is the anal membrane. Starting from the 5th week of human embryo development, the anal membrane begins to indent and gradually deepen, and the anal membrane ruptures at the 8th week, connecting the rectum with the outside world. If the cloacal septum does not grow fully, it can lead to high rectal anorectal anomalies: in boys, it is rectourethral fistula, and in girls, it is rectovaginal fistula; if the anal membrane does not rupture, anal atresia will occur. Dickinson (1967) proposed that vascular damage in the hindgut region during early intrauterine development is the cause of cystic colon anomalies. Bourdelat et al. (1988) studied the arterial supply of the anal-rectal region in human embryos and fetuses, proposing that vascular ischemia is the basis for the occurrence of anal-rectal anomalies. They found that the anal-rectal vessels originally come from the superior rectal artery of the inferior mesenteric artery, which is a terminal artery without anastomotic branches, but can fully ensure the development of the hindgut. Chadha et al. believe that the vascular damage hypothesis can fully explain the etiology and a series of anatomical characteristics of short colon anomalies: vascular damage near the descending urorectal septum in the cloaca around the 4th week of pregnancy can affect the differentiation of the cloaca; vascular damage near the blind end of the developing hindgut can affect the development of the cloaca; vascular damage in different ranges of mesenteric vessels determines the pathogenesis and clinical classification of congenital short colon.

　　Secondly, the pathogenesis

　　1. Chadha et al. believe that 'congenital bag colitis and anal-rectal underdevelopment' can accurately summarize the pathological characteristics and changes of congenital short colon. Narasimharao et al. divided congenital short colon into 4 types: Type I: without normal colon, the short colon is bag-like, and the ileum is directly connected to it; Type II: between the ileum and bag colon, there is a short segment of cecum; Type III: between the ileum and bag colon, there is a segment (7-8 cm long in neonates) of normally shaped colon; Type IV: the colon is close to normal, but the distal part (rectum and sigmoid colon) is bag-like. Type IV is only damage to the distal vessels of the inferior mesenteric artery; Type III is damage to the proximal vessels of the inferior mesenteric artery; Type II is damage to the main trunk of the inferior mesenteric artery, with the blood supply of the short colon originating from the superior mesenteric artery; Type I, in addition to damage to the main trunk of the inferior mesenteric artery, also has damage to the most distal branch vessels of the superior mesenteric artery. Type I is the most common, and Type IV is rare.

　　2. Most short colons are dilated and thickened in a bag-like or cystic shape. Type I, extremely similar to an inverted stomach, occupies most of the abdominal cavity; Type II, III, due to the presence of a segment of cecum and ascending colon, the short colon is mainly located in the left abdominal cavity; Type IV, the short colon is located in the lower abdomen. The ileum, cecum, or a segment of colon is connected to the upper part of the short colon; the distal part of the short colon is short and thin, representing an underdeveloped rectum. Often connected to the bladder, urethra, or vagina through a wide fistula. The short colon lacks the colon bands and pouches; the omentum is also underdeveloped, appearing as a cord-like structure connected to the short colon; the gastrocolic ligament is short and thin. Some short colons have poor peristaltic function, and intestinal peristalsis is not seen even after decompression; some short colons have peristaltic function and can maintain defecation through the fistula. Histological examination shows changes in mucosal inflammation in addition to full-thickness hypertrophy and edema. The enteric ganglion cells in the short colon can be normal, reduced, or absent.

　　Clinical manifestations are typical of low intestinal obstruction, with no meconium excretion or ectopic excretion of meconium after birth, followed by vomiting, and if feeding symptoms begin after birth, they will inevitably worsen. Frequent vomiting can lead to dehydration and aspiration pneumonia, and a delayed diagnosis will inevitably cause intestinal perforation, peritonitis, and sepsis, causing the condition to deteriorate rapidly, ultimately leading to death. Congenital rectal and anal malformations in patients are young, with low weight and delicate tissues and organs, requiring precise and difficult surgery, with high technical requirements for the surgeon, so patients should choose to seek medical attention and surgery at specialized hospitals with a certain level of technical standards to avoid difficulties in postoperative management.

　　Most patients develop symptoms soon after birth, with clinical manifestations similar to high rectal and anal malformations: anal atresia is trace-like, without swelling or impact sensation; some children have normal anal development, only rectal atresia, without fistula or a small fistula, and present with symptoms of low intestinal obstruction at birth: obvious abdominal distension, tense abdominal wall, luster, and dilated superficial veins; in those with larger fistulas, meconium and gas are excreted through the urethra or vagina, although the position of defecation is abnormal, there is no abdominal distension due to smooth defecation, so the time of seeking medical attention or onset is later. If there is a reduction or absence of enteric ganglion cells in the short colon, there may be symptoms of chronic constipation.

　　1. Li Zhen Dong and others reported 10 cases of children, 9 cases of short colon with fistula, among which 4 cases were colovesical fistula, 3 cases were colovaginal fistula, and 2 cases were colourethral fistula; Chadha and others reported 32 male children, 29 cases with colovesical fistula, and 3 cases without fistula, respectively, type II, III, IV short colon children, type II and III, the fistula was replaced by a short fibrous cord attached to the posterior wall of the bladder; among 9 female children, 6 cases had high colovaginal fistula, and another 3 cases were anal fistula.

　　2. Associated malformations: Li Zhen Dong and others reported 10 cases of children, 8 cases with Meckel diverticulum, absent appendix, short small intestine, abdominal wall hernia, and congenital heart disease and other malformations; Chadha and others reported 41 cases of children with 53 malformations in the urogenital, digestive, skeletal, cardiovascular and other systems: among them, 14 cases of vesicoureteral reflux, 5 cases of double appendix, unilateral renal agenesis, hydronephrosis, Meckel diverticulum, and 4 cases of partial sacral maldevelopment each, 3 cases of anal fistula, trace appendicitis, incomplete intestinal rotation, incomplete descent of the unilateral testis, septate vagina, multiple vertebral hemivertebrae each 2 cases, and other rare malformations.

　　3. High rectal anal atresia with congenital short colon has a higher incidence, therefore, after the clinical diagnosis of high rectal anal atresia, further X-ray examination should be performed to determine whether there is congenital short colon. The characteristic changes of X-ray are the main basis for diagnosing congenital short colon. The imaging characteristics are: there is a large liquid plane on the upright abdominal flat film, the width exceeds 50% of the maximum transverse diameter of the abdominal cavity; urethral or vaginal fistulography shows a giant sac-like change in the distal colon. It is also necessary to perform a comprehensive examination of the child as much as possible to discover other lethal malformations.

　　The etiology of this disease is not clear, and it may be related to environmental factors, genetic factors, dietary factors, and emotional and nutritional factors during pregnancy. Therefore, it is impossible to prevent this disease directly. Early detection, early diagnosis, and early treatment are of great significance in preventing this disease. Other diseases, including infants and young children with lactose intolerance, may also have similar clinical manifestations. Lactase enzyme testing can be used to clarify the diagnosis.

　　1. Abdominal palpation:The shape of the colon can be felt as a square-shaped expansion.

　　2. Rectal examination:It is quite helpful for diagnosis. In addition to excluding organic lesions such as congenital atresia and stenosis of the rectum and anal canal. First, a sense of emptiness in the rectal ampulla is felt, with no large amount of meconium retention, and after the finger is withdrawn, a large amount of meconium and a lot of臭气 are discharged immediately. After this 'explosive' excretion, abdominal distension also improves.

　　3. X-ray examination:X-ray is one of the important means of diagnosis for this disease. Abdominal flat film shows colon gas distension, presenting as a continuous hollow columnar transparent area around the abdomen. The small intestine is also distended, but there is no large liquid level that can be distinguished from small intestinal obstruction. The absence of gas in the rectal ampulla is also an important differential point. Some people suggest taking inverted anteroposterior and lateral abdominal and pelvic X-rays for colonic allergy, and if the gas cannot rise into the rectum, the diagnosis is more reliable.

　　4. Barium enema X-ray imaging:For cases with lesions in the rectum and sigmoid colon, the accuracy rate is over 90%. The lesion site shows persistent narrowing of the rectum, connected to the dilated intestinal segment in the shape of a funnel. Dynamic imaging shows strong and regular colonic peristalsis. After barium enema, due to the thickening of the intestinal wall and mucosa, obvious folds are seen in the intestinal cavity, similar to the normal jejunal folds, known as the so-called 'jejunalization of the colon' change. Most children cannot excrete barium in time, and the observation of barium excretion function is an important diagnostic method for neonatal megacolon. When complications such as colitis occur, X-rays show blurred outlines of the proximal dilated colon, with a rigid appearance and multiple irregular burrs protruding.

　　5. Rectal biopsy:In theory, rectal biopsy is the most reliable method for diagnosing the disease. However, due to the narrow anal canal in neonates, the tissue to be sampled needs to be 4.0 cm or more from the anal margin, and the depth also needs to reach the full thickness of the rectum, making the operation difficult. In addition, the rectal ganglion cells are sparse, and there are no ganglion cells in the internal anal sphincter, with the tissue sampling position being too low, which is prone to misdiagnosis. Moreover, neonates, especially preterm infants, have particularly small ganglion cells with poor nuclear visibility. Only a pathologist with rich experience can make a diagnosis. Therefore, except for a few cases, it is not necessary to perform this examination in all cases.

　　6. Rectal pressure measurement method for colonic allergy:Due to the lack of anal sphincter relaxation caused by rectal distension in children with congenital megacolon, as well as the lack of anal-rectal reflex, when the balloon is inflated, if the pressure in the anal canal does not decrease after stimulating the rectal wall, it can be suspected as congenital megacolon. Therefore, in recent years, some people have advocated the use of rectal pressure measurement as a method for diagnosing congenital megacolon.

　　I. How to make Banana Rock Sugar - Dietary Therapy for Congenital Megacolon

　　1. Recipe ingredients:

　　Banana 2 pieces, rock sugar to taste.

　　2. Preparation method:

　　Boil the water and eat the soup.

　　II. How to make Horsehoof Jellyfish Soup - Dietary Therapy for Congenital Megacolon

　　1. Recipe ingredients:

　　Horsehoof 60 grams, jellyfish 50 grams.

　　2. Preparation method:

　　Boil the above materials into water and drink.

　　Surgery is the only treatment method. The surgical method is divided into initial treatment and radical surgery.

　　1. Initial treatment

　　(1) Stoma surgery: includes short colon window (lateral wall stoma) or superior intestinal tract (ileum or colon) stoma. After surgery, there is a tendency to have stoma stenosis and mucosal prolapse. Intestinal fistulae often cause diarrhea, while colonic fistulae often cause the entire colon to prolapse outward. If accompanied by colovesical or urethral fistula, urinary tract infections are more likely to occur, and children with vesicoureteral reflux are more prone to urinary tract infections.

　　(2) Short colon terminal separation (for those without fistula) or ligation (for those with fistula) followed by colonic stoma surgery. This procedure can avoid urinary tract infection, but it has certain difficulty due to the high expansion of the short colon, which needs to be decompressed before handling the terminal. The stoma method is short colon terminal stoma or fenestration.}

　　(3) Partial resection and整形 of bag-shaped colon (making the bag-shaped colon tubular, retaining a diameter of 15-20mm) followed by stoma surgery. This method can maximize the retention of the colon, but sometimes the retained colon does not have peristaltic function.

　　2, Radical surgery is the anal成形术 via abdominal perineal or sacral tail approach.

　　(1) Bag-shaped colon resection, ileal or colonic pull-through anal成形术.

　　(2) Partial resection and整形 of bag-shaped colon, followed by a pull-through anal成形术.

　　(3) Treatment plan:

　　①Disease classification: Chadha et al. believe that different surgical methods indicate complex conditions and lack standardized diagnosis and treatment plans. For this reason, they have formulated a more detailed treatment plan.

　　Divide the condition of type Ⅰ, Ⅱ, Ⅲ children into 3 categories (A, B, C):

　　A, Good condition; no other life-threatening anomalies; short colon is good.

　　B, Poor condition; other life-threatening anomalies; short colon perforation with peritonitis.

　　C, Poor blood supply, short colon thin or necrotic due to ischemia.

　　Divide the condition of type Ⅳ children into 2 categories (D, E):

　　D, Good condition; no other life-threatening anomalies; short colon is good.

　　E, Poor condition; other life-threatening anomalies.

　　②Initial surgery: Implement different initial surgeries for the aforementioned 5 types of children.

　　A, Fistula separation and ligation, short colon tubular shaping and stoma.

　　B, Fistula separation and ligation, short colon terminal stoma or fenestration; for those without fistula, short colon fenestration.

　　C, Short colon resection and colonic or ileal stoma.

　　D, Right hemi-colonic stoma, short colon fistula separation and ligation, and terminal stoma or short colon resection and terminal colon stoma.

　　E, Right hemi-colonic stoma. After 2 weeks to 1 month, if the child's condition or associated anomalies improve, perform surgery ④.

　　③Radical surgery: Perform a pull-through anal成形术 or a single-hole anal reconstruction at 4 to 18 months of age for the child.