Congenital megacolon is a common gastrointestinal malformation in infants characterized by partial or complete colonic obstruction, combined with the absence of ganglion cells in the intestinal wall. The disease has been recognized and developed for more than 200 years, first reported by Ruysch in 1691, and then described in detail and systematically by Hirschspmng at the Pediatric Congress in Berlin in 1886, after which the disease was named Hirschspmng's disease in his honor. The term megacolon was advocated by Mya (1894), and in 1901 Tittle first suggested that congenital megacolon was associated with ganglion cell deficiency; Tiffin et al. in 1940 stated that megacolon was the result of disturbed peristalsis of the intestinal wall in the early stages of ganglion deficiency; and in 1964 Ehrenpries discussed in detail the etiology and pathogenesis of Hirschs-prong's disease. The etiology and pathogenesis of Hirschs-prong disease were discussed in detail by Ehrenpries in 1964. It was not until 1950 that Swenson pathologically distinguished ganglion-deficient megacolon from other types of megacolon. The disease is characterized by the absence of intermuscular nerve cells in the distal part of the affected bowel segment, which produces spastic contractions, narrowing and loss of peristalsis. The proximal bowel segment is dilated and hypertrophied secondary to compensatory dilatation. The incidence rate is 1 case in 2000-5000 newborns, second only to rectoanal malformations, and ranks second in neonatal gastrointestinal malformations. According to the data of Shanghai area (1966-1975), the incidence of digestive tract malformation accounts for 24.67% of congenital malformations. And this disease accounts for the 4th place of digestive tract malformations. According to Passarge et al. reported 414 cases, the ratio of male to female is 5-10:1, and there is a clear tendency of familial morbidity, the data suggest that this disease may be polygenic inheritance. In the past 20 years, due to the progress of histology, histochemistry, electron microscopy, immunohistochemistry and other research tools. People in the congenital megacolon pathology, physiology and histology, embryonic development, genetic diagnosis and treatment have made great progress.1. Neonatal, infantile megacolon
(1) Clinical manifestations
The vast majority of children born 48 hours or more after the absence of meconium, followed by vomiting and abdominal distension, the occurrence of intestinal obstruction. In a few cases, a small amount of hardened meconium may be passed 3 to 4 days after birth. The prominent symptom is intractable constipation a few weeks after birth, which is initially relieved by enemas, but later becomes more and more intractable, necessitating reliance on enemas for fecal evacuation. Due to the stagnation of feces, colon dilatation, bacterial reproduction, often complicated by small bowel, colitis, children with frequent constipation suddenly changed to diarrhea, fever and colon distension, but still a few days between the feces, defecation. And once defecation is violently dilute watery and strange smelling feces in large amount. The general condition deteriorates rapidly, with abnormal abdominal distension, refusal of food, vomiting, severe dehydration and electrolyte disorders, and shock soon develops. Without timely and correct treatment, the mortality rate is very high.
(2) Diagnosis and differential diagnosis
1) Diagnostic points:
Any newborn who has no meconium in the first 24-48 hours after birth or can only expel meconium after finger-excavation or enema, and is accompanied by abdominal distension and vomiting should be suspected of congenital megacolon. The diagnosis is usually made on the basis of clinical symptoms, combined with the following tests.
1. Abdominal palpation: a box-shaped dilated colon can be felt.
2. Rectal palpation: quite helpful in diagnosis. In addition to exclude the rectum, anus without congenital atresia and stenosis and other organic lesions. First of all, finger feeling rectal pot belly has a sense of emptiness, without a lot of meconium stagnation, and finger pull out, then there is a large amount of meconium and a lot of odor discharged, this "outbreak" after the excretion, at the same time, abdominal distension that is better.
3. X-ray examination: X-ray is one of the important means of diagnosis of this disease, abdominal plain film can be seen in the colon inflatable dilatation, in the periphery of the abdomen is a continuous empty column translucent area, the small intestine is also flatulence, but there is no large liquid plane can be differentiated from the small bowel obstruction. The absence of gas in the recto-pubic abdomen is also an important point of differentiation. It has been suggested to do inverted position ortho-lateral abdominal and pelvic radiographs, if the gas can not rise into the rectum, the diagnosis is more reliable.
4. Barium enema radiographs are more than 90% accurate in diagnosing lesions in the rectum and sigmoid colon. The lesion site can be seen in the rectum persistent stenosis, funnel-shaped and dilated intestinal segments, dynamic image shows strong peristalsis of the colon and regular, barium discharge due to the thickening of the intestinal wall and mucosa, the intestinal lumen see obvious folds, similar to the normal jejunum folds, known as the so-called "jejunostomy" changes. Most of the children can not discharge barium in time. Observation of the function of barium discharge is an important diagnosis of neonatal megacolon. When complicated by colitis, the X-ray shows a blurred outline of the proximal dilated colon, with a rigid shape and most of the irregular burrs protruding.
5. Rectal biopsy: theoretically, rectal biopsy is the most reliable diagnosis of this disease. However, due to the narrow anus of newborns, and cut the tissue from the anal verge of more than 4.Ocm, and the depth of the rectum to reach the whole muscle layer, so the operation is difficult. In addition, the rectal ganglion cells of the anal canal are scarce, and some ganglion cells of the internal sphincter are absent, so it is easy to misdiagnose the disease because of the low location of the excised tissue. In addition, in newborns, especially premature infants, the ganglion cells are particularly small and their nuclei are not well visualized, so the diagnosis can only be made by a pathologist with extensive experience in this field. Therefore, except for a few cases, it is not always necessary to do this test.
6. Intrarectal pressure measurement: Because of the lack of congenital megacolon in children with rectal dilatation of the anal sphincter caused by the lack of anal rectal reflex, so when the balloon inflation, stimulation of the rectal wall of the anus if the pressure does not fall, that is, suspected of congenital megacolon. Therefore, in recent years, some people advocate the use of intrarectal pressure measurement as a method of diagnosing congenital megacolon.
2) Differential diagnosis
1. Neonatal simple meconium constipation: neonatal intestinal peristalsis is weak, can not be particularly thick meconium discharge, can be a few days after birth no meconium, which and megacolon within the first few days of the symptom can be exactly the same. However, children with simple meconium constipation can pass meconium after saline enema and will not be constipated again.
2. Congenital ileocecal atresia: After saline enema, there is no meconium discharge, and only a small amount of grayish-green secretion is discharged. Abdominal X-ray in upright position, in intestinal atresia and megacolon are seen intestinal lumen enlargement and liquid plane, but in ileal atresia there is no colon dilatation, the whole pelvis is blank and airless. Barium enema X-rays show a small, pouch-shaped shadow of the colon (small or fetal-type colon), but this is often not easily differentiated from the signs of total colonic aganglionosis.
3. neonatal sepsis: neonates can have peritonitis secondary to sepsis, umbilical cord infection, etc. At this time, the child may present with abdominal distension, vomiting, constipation or diarrhea, etc., which is not easy to distinguish from neonatal megacolon complicating small bowel, colitis cases, but there is no history of delayed expulsion of meconium. x-rays show signs of paralytic bowel obstruction. Sometimes differential diagnosis can be made with appropriate supportive therapy, close observation of the condition, and barium enema to make a definitive diagnosis.
4. Congenital malrotation: Vomiting and abdominal distension in congenital malrotation can be confused with congenital megacolon. However, fetal fecal matter is excreted normally. A barium x-ray of the bowel showing an abnormal position of the right half of the colon is of great discriminatory value.
2. Childhood megacolon
(1) Clinical manifestations
Most children have a history of constipation, abdominal distension, and vomiting during the neonatal period. Initially, the child's condition may become normal in a few weeks or days, but thereafter the child may begin to have constipated stools, and may not pass stools for several days, which may require the insertion of anal pessaries, the use of laxatives, or the use of enemas to evacuate the bowels. Symptoms gradually worsen and constipation becomes more and more stubborn. Children may suddenly develop symptoms of small bowel and colitis; or, due to excessive accumulation of feces in the colon, colonic obstruction may occur. There have also been reports of children with megacolon suddenly developing extreme abdominal distension, high fever and other manifestations similar to acute gastric dilatation and rapid death. Children with megacolon can sometimes pass a small amount of feces on their own, but it does not relieve abdominal distension and fecal accumulation in the megacolon, and sometimes constipation and diarrhea can occur alternately.
A physical examination reveals a distended abdomen, which contrasts sharply with a thin chest and limbs. The abdominal bulge is most pronounced in the upper abdomen, with a flat or flared umbilicus, thin abdominal skin, and subcutaneous veins. Palpation can be felt in the left iliac fossa in the enlarged intestinal segment of the accumulation of fecal mass, palpation can be seen in most cases of intestinal peristalsis wave; auscultation can be heard hyperactive intestinal sounds; percussion due to the intestinal lumen with a large amount of gas accumulation, loud drumming can occur; rectal palpation examination, the majority of children in the rectum potbellies can be empty feeling, but for spastic stenosis of a short segment of the person, finger palpation can be touched fecal matter in the potbellies. The children are usually in poor general condition, developmental delay, malnutrition, pale, thin, with anemia, hypoproteinemia and so on. Due to low resistance, infections such as pneumonia and sepsis can easily occur.
(2) Diagnosis and differential diagnosis
1) Diagnostic points:
Based on the history of constipation and abdominal distension and other signs, combined with the finger diagnosis, it is not difficult to confirm the diagnosis, but the following tests are still needed to assist in the confirmation if necessary.
1. Barium enema X-ray examination, can be seen without ganglion cells intestinal segment spasm narrowing, the length of the narrowed area from the anus upward extension, up to the sigmoid colon, descending colon, and some even up to the splenic flexure or transverse colon. In the proximal part of the narrowed segment, an abnormally dilated colon can be seen, which is called the enlarged segment. Sometimes it is located between the two segments, showing a clear funnel-shaped image. However, in short-segmented cases, the stenosis is 6.0-7.O cm or shorter, and the stenosis is not visible on X-ray, and it seems that the rectum is immediately dilated from the anus. After removing the anal tube, the barium could not be emptied automatically. After 24-48h, a large amount of barium can still be seen trapped in the enlarged colon on fluoroscopy.
2. When the diagnosis is in doubt, a biopsy of the rectal surface mucosa can be taken for histochemical staining with acetylcholinesterase. Congenital megacolonosis of the intestinal mucosa of the lower layer of acetylcholine lipase increased, can be seen in the proliferation of acetylcholine lipase strong positive staining of parasympathetic nerve fibers; and normal rectal mucosa is negative, the specific method see neonatal, infant and young child megacolon section.
3. Intrarectal manometry and rectal biopsy are both valuable in the diagnosis of this disease. See megacolon nodes in neonates, infants, and children.
2) Differential diagnosis:
Megacolon in children must be differentiated from idiopathic megacolon: the exact cause of megacolon in children is not known. Some, such as habitual constipation (its clinical features in addition to persistent constipation, there is significant rectal dilatation), anal sphincter spasm, sigmoid colon overgrowth, etc., may be related to the formation of megacolon. In recent years, it is also believed that this disease is a special type of congenital megacolon, which is also called "ultra-short segment megacolon" because of its extremely short ganglion cell-free bowel segments and abnormal internal sphincter function. In children with idiopathic megacolon, the symptoms of constipation and abdominal distension do not exist in the neonatal period, but appear in toddlers and children, and the symptoms gradually worsen. Symptoms can be relieved with appropriate conservative treatment. On palpation, a large fecal mass can be palpated in the recto-pelvic abdomen, unlike in congenital megacolon, where the pelvic abdomen is mostly empty. A barium enema reveals an abnormally dilated rectum from the anus upward, with no obvious spastic narrow bowel segments in the distal rectum. If the definitive diagnosis is in doubt, a rectal biopsy may be performed, and the ganglion cells of the rectal wall in idiopathic megacolon are normally developed. In addition, certain atypical cases must be carefully analyzed and differentiated from a range of constipating disorders.
3. Specialized types of congenital megacolon
(1) Total colonic aganglionosis
This disease was first reported in 1948. It is actually a hypertrophy of the entire colon without dilatation, so it is really inappropriate to call it megacolon. The ileocecal terminal hypertrophy and dilatation is often present, so some people refer to the absence of ganglion cells in all of the colon and part of the ileocecal terminal as total colonic aganglionosis. Many children with this disease die in the neonatal period without a definite diagnosis, so total colonic aganglionosis is considered to be very rare. However, in recent years, there has been a gradual increase in the number of cases reported in the literature, and the incidence of the disease ranges from 5% to 10%, suggesting that it is not rare.
1) Clinical manifestations
The more extensive the ganglion cell-free intestinal segment, the more severe the symptoms. Most of them present in the neonatal period with delayed expulsion of meconium, abdominal distension, vomiting and constipation, which can be temporarily relieved by anal dilatation, enema and laxatives. However, constipation is recurrent and more frequent than in normal megacolon. The difference with the general congenital megacolon is that the fecal reflex cannot be induced during rectal examination, and there is no large amount of odor and fecal discharge.
2) Diagnosis
The diagnosis of total colonic aganglionosis is quite difficult, and confirmation of the diagnosis often relies on pathohistologic examination during surgery. X-ray examination is an indispensable means of diagnosing this disease, abdominal plain film can only understand the proximal intestinal lumen dilatation and insufflation, barium enema is of greater value in confirming the diagnosis. x-ray signs are characterized as: rectum is spastic, no dilatation; all the colon diameter is normal or less than normal, but different from the fetal type of small colons; the colon is not dilated. The pouch shape disappeared and the bowel wall became smooth. When the pressure of the enema is increased, barium can flow back into the ileum, but there is no obvious dilatation of the colon; the length of the colon is shorter than that of a normal child, especially the left half of the colon is shorter, and the splenic flexure of the colon is seen to be obtuse and shifted inward, and abnormal peristaltic movement of the colon can be seen during the enema; the lateral film of the spinal column anteriorly, and there is no dilatation of the inflatable transverse colon, which is seen in the general congenital megacolon.
(2) Short segmental congenital megacolon
This type accounts for 25% of the total number of megacolons. It is characterized by the absence of ganglion cell intestinal segments confined to the end of the rectum, and the spastic stenotic segments do not exceed 7.0-8.0 cm, so it is called short-segment megacolon.
1) Clinical manifestations
Clinical symptoms are milder than those of the common type of megacolon. Constipation occurs in about half of the cases before the age of 1 year, and in the other half, constipation becomes obvious only at the age of 1 to 2 years or even at the age of 10 years. The constipation is intermittent at the beginning, but later it becomes persistent, and anal pessaries or enemas must be inserted in order to evacuate feces. The children are usually in good general condition with few complications, and only a few cases have abdominal distension. During rectal examination, the finger has to pass through the spasmodic segment to enter the empty and enlarged intestinal lumen. Barium enema shows that the spastic stenotic segment occupies only a few centimeters of the end of the rectum, and there is obvious dilatation of the intestinal lumen in the upper part of the segment. However, after 2 weeks of enema and fecal evacuation, the dilated lumen can be significantly reduced. To confirm the diagnosis, a rectal biopsy can be performed to demonstrate the absence of intermuscular plexus cells in the spastic stenotic bowel segment.
(3) Segmental intestinal spastic megacolon
This disease is characterized by the absence of intermuscular ganglion cells in only one segment of the colon, and the upper and lower intestinal walls of the diseased segment are normal.
1) Clinical manifestations and diagnosis
Spastic stenosis of a segment of the colon presents with the same symptoms as those of a normal congenital megacolon of the same height. A barium enema reveals a spastic stricture in one segment of the colon. The diagnosis is confirmed by intraoperative biopsy, which confirms the absence of intermuscular ganglion cells in the spastic stenosis.
2) Treatment
Treatment principles:
1. Newborns and infants with poor general condition, severe symptoms, combined with small bowel colitis or severe congenital malformations, it is suitable for temporary enterostomy. When the general condition improves, about 6 to 12 months before radical surgery.
2. The general condition of the child is good, if the diagnosis is clear, the hospital is well-equipped, the anesthesiologist and surgeon are skilled, in order to reduce the burden on the parents can also be a radical operation.
3. If the child's general condition is good, conservative treatment can be used first.
Non-surgical treatment:
Applicable to newborns, children with limited and short-segment megacolon.
1. Enema therapy to assist defecation and exhaustion, reduce abdominal distension and vomiting, in order to ensure normal milk intake, to maintain the gradual growth of the child, and then consider surgery according to the severity of symptoms. The method of enema is to use 24-26 anal tube inserted through the spasm of intestinal segments, and then inject 50ml of saline after exhaustion, retaining the anal tube; massage the abdomen, so that the gas and feces as much as possible through the anal tube to empty.
2. Dilation of rectum and anal canal: once a day for 30 minutes. Dilator from small to large size.
3. Auricular acupuncture and acupoint closure therapy: acupuncture auricular kidney, sympathetic, subcortical, lower rectal and other points, once a day, 30 minutes each time; acupoint closure: renal acupuncture point injection of ginseng injection, colon acupuncture point injection of neostigmine; or alternating between the two, once a day.
4. Internal Chinese medicine: commonly used to tonify qi and help yang, such as ginseng, raw astragalus, balsam pear, hedgehog, thick park; qi and attack the lower part of the medicines, such as yulin, petunia, thick park, hedgehog; beneficial to qi and blood, moistening dryness and stasis medicines, such as ginseng, angelica sinensis, the raw land, the ripe ground, cistanches, thick park, hedgehog, peach kernel, safflower.
Surgical therapy:
1. Colostomy: it is suitable for infants who are not effective in observing conservative therapy for a period of time and whose symptoms gradually worsen. Most scholars advocate that a colostomy is preferable because it preserves the maximum area of colonic absorption. Moreover, a second radical surgery can be performed in a single session to close the fistula.
2. Radical surgery: the requirements of surgical trauma, safety, reduce or not destroy the pelvic nerve plexus, postoperative does not affect defecation and reproductive capacity. It is suitable for infants over 6 months old and low segmental spastic megacolon. Commonly used surgical methods are: ① colon and rectal mucosa peeling muscle sheath drag out method: after entering the abdominal cavity, at the level of the bladder top, cut off the colon, peel off the mucosa and skin of the rectal-anal tube, and then excise the diseased section of the colon and the rectum (pay attention to the lack of ganglion cells of the intestinal segments of the total excision, including spastic segment, migrating segment and dilated segment), the remaining colon is fully free, set of people in the rectal muscle sheath, suture around the colon. . The excess colon was dragged out and the lower end was sutured and fixed to the rectum at the upper end of the anus. And first of all, the posterior wall of the rectal muscle sheath together with the internal rectal sphincter together with longitudinal incision, can reduce abdominal distension and postoperative colitis and other complications, postoperative rectal sheath retained catheter drainage, can avoid the occurrence of abscess in the muscle sheath; ② colonic resection, rectal post-colonic dragging out of the rectum (Duhamel surgery): along the rectal bladder depression of the peritoneal reflexes of the peritoneum cut the peritoneum of both sides of the rectum, rectal anterior wall is not incised in the pubic bone The anterior wall of the rectum was not incised, and the rectum was cut off at the upper edge of the pubic symphysis at 2.O cm, and in the posterior median of the rectum, the presacral fascia and the intrinsic fascial sheath of the rectum were obtusely separated to the subcutis of the perineum, and the anus was dilated, and the posterior anal half was incised in the posterior anal area along the junction of the skin and mucous membranes, and the colon was then prepared, and it was dragged out by the posterior incision of the anus, the posterior margins of the wall of the colon were sutured with the lower margins of the anal canal odontocoeles incision, the anterior wall of the rectum was sutured to the anterior wall of the colon with a full-toothed vascular forceps. The anterior wall of the rectum and the anterior wall of the colon were clamped with a full-toothed vascular forceps, and then put into the anal canal and the rectum for 3.0-4.O cm to be clamped to death.
3. duhamrl surgery: in recent years, in order to make the rectum and colon open and avoid the gate syndrome, more than a variety of special clamp, that is, modified Duhamel surgery. That is, with a ring-shaped clamp, the rectum and colon clamped together in the surgical method. The specific operation method is: the bottom leaf of the clamp is put into the colon cavity, the upper leaf is put into the rectal cavity, the rectal stump is pulled out from the ring of the upper leaf, and the two leaves are properly clamped, so that the rectum and the anterior wall of the colon are clamped together, and the excess rectal stump is resected within the ring, and then the top of the rectum that has been refracted from the abdomen is fixed to the colon for several pins, and about 1 week later, the clamp is detached with the necrotic intestinal wall, and then a new rectal cavity is formed. The advantages of this procedure are: the posterior wall of the colon is connected to the posterior wall of the anal canal, and the anterior wall of the rectum is connected to the anterior wall of the colon to form an oblique anastomosis, eliminating the blind pouch and avoiding the complication of the gate syndrome.
4. Rectal ectopia colon dragged out of the anus outside the colorectal anastomosis (Swenson method): after the abdomen is opened, the peritoneum is incised in the rectum, bladder, or uterine recesses, and the perirectal area is freed until it is freed to the vicinity of the anus. The closure is cut above the bladder and the rectum is turned out and dragged out through the anus. The rectal wall was incised at the dentate line of the rectum, and a long vascular forceps was inserted from this incision to hold the free proximal colonic stump suture, and dragged to the anus to suture the rectum to the opposite end of the colon in 2 layers, with the anastomosis being as low as possible and generally no more than 2.O cm from the anal verge.After the anastomosis was completed, the colon was returned to the anus.
5. Transsacrococcygeal rectal muscle layer resection method: the patient to take the prone buttock position, in the anus and coccyx between the incision of the skin is about 3.Ocm long, the anus and the puborectalis muscle to the up and down respectively, the operator's left hand index finger to put people in the rectum as a guide and sign or inserted into the anus with the balloon tube so that the rectum is puffed up in the posterior wall of the rectum to make a longitudinal incision, the deepest layer of the mucous membranes, the length of the barium enema according to the preoperative and intraoperative frozen section examination. The length of the incision depends on the preoperative barium enema and intraoperative frozen section examination of the intestinal canal without ganglion cells. The caudate may be resected for adequate exposure so that 1 longer strip of muscle tissue can be removed. After resection of the internal sphincter, the levator ani muscle and puborectalis muscle are put back in place, the anal caudal fascia is sutured, and a drainage strip is placed in the wound and removed after 24 hours.
6. Total colon type surgery (Mavtin method): that is, the rectum after the ileum dragged out of the rectum ileum lateral anastomosis (Duhamel method). However, the lesion colon can not be fully resected, must retain the sigmoid colon and distal ileum in parallel, side by side anastomosis, in order to facilitate the absorption function of the residual colon, so the Martin method.