Hirschsprung's disease
Introduction
Introduction to congenital megacolon The congenital giant intestine (Hirschsprung's discase) is a congenital intestinal malformation in children due to the persistent collapse of the intestines at the distal end of the rectum or colon and the stagnant colon of the feces, which makes the intestine thick and dilated. In children with congenital megacolon, acute bowel obstruction occurs in the neonatal period, and open laparotomy is not uncommon. In the elderly, misdiagnosis of fecal stone when the tumor is open, but also often due to atypical symptoms and delay diagnosis and treatment, misdiagnosis, mistreatment. basic knowledge The proportion of illness: 0.029% Susceptible people: infants and young children Mode of infection: non-infectious Complications: intestinal obstruction
Cause
Cause of congenital megacolon
Environmental factors (30%):
Including environmental factors before, during birth, and after birth. Some people have reported that some premature babies have "megacolon" due to lack of oxygen. Hypoxia can cause severe "selective circulatory disorders" that alter the function of immature distal colonic ganglion cells in premature infants. It has also been reported that surgical damage can cause megacolon (acquired megacolon).
Innate developmental factors (25%):
Embryology studies have confirmed that from the 5th week of embryonic, the neural tube derived from the neural crest originates from the head to the caudal side along the vagus nerve fibers. The entire migration process is completed by the 12th week of the embryo. Therefore, no ganglion cell disease is caused by developmental pause before the 12th week of the embryo. The earlier the pause, the longer the intestinal segment without ganglion cells. The rectum and sigmoid colon at the end are the last evolution of neuroblasts and are therefore the most common lesion. Due to the complete absence or reduction of the ganglion cells of the muscular wall of the intestine and the submucosal plexus, the diseased intestines lose their peristalsis, often in a paralyzed state, forming a functional intestinal obstruction, which lasts for a long time, and the upper colon of the obstruction is dilated, the intestine The wall thickens to form the congenital megacolon. As for the original cause of developmental pause, it may be caused by motor neuron developmental disorder in the early pregnancy of the mother due to viral infection or other environmental factors (metabolic disorders, poisoning, etc.).
Genetic factors (15%):
Some people think that megacolon genetic factors may be abnormal on the 21st chromosome. The megacolon is a polygenic hereditary disease with genetic heterogeneity.
Pathogenesis
1. Pathological and neuroimmunological histochemical changes
Typical changes can be seen in the affected intestines of Hirschsprung's disease, namely the obvious stenosis and dilatation, the stenosis is located at the distal end of the dilatation, usually at the junction of the rectosigmoid colon, within 7 to 10 cm from the anus, the narrow intestine Small, and the diameter of the enlarged intestine is very different, and its surface structure is not very different. It forms a funnel-shaped transition zone (ie, the distal transition zone of the dilatation section) with the enlarged colon junction. This area is originally a narrow segment due to the proximal intestinal tube. Peristalsis, pushing the contents of the intestine to move forward, long-term compression promotes the proximal intestine of the stenosis segment to expand into a funnel shape, and the dilatation segment is mostly located in the sigmoid colon. In severe cases, the transverse colon can be spread, and the intestinal tube is abnormally enlarged, and its diameter is larger than normal. ~ 3 times, the largest can reach more than 10cm, the intestinal wall is thick, the texture is tough as leather, the surface of the intestines loses rosy luster, slightly pale, the colon band becomes wider and the muscle lines are split in longitudinal stripes, and the colonic bag disappears. Intestinal peristalsis is rare, the intestine contains a large amount of feces, and occasionally touches the fecal stone. When the intestine wall is cut, the original ring muscle is seen, and the longitudinal muscle loses the normal proportion (2.2:1), and even the ratio Inverted, the thickness of the intestinal wall is 2 times of the stenosis, the intestinal mucosa is edematous, bright, congested and rough, easy to hemorrhage, sometimes visible superficial ulcer, the main pathological changes of Hirschsprung's disease are located at the distal end of the dilated segment In the narrow intestine, the stenosis of the intermuscular plexus (Auerbach plexus) and the submucosal plexus (Meissner plexus), the ganglion cells are absent. In the distal segment, it is difficult to find the plexus, the nerve fibers are thickened, the number is increased, and the arrangement is wavy. Sometimes, although individual ganglion cells are found, the morphology is not normal. The normal nerve plexus is gradually found in the proximal colon wall of the stenosis, and the ganglion cells are gradually increasing. The mucosa glands exhibit different degrees of lesions, and the colonic lamina propria is widened. And accompanied by lymphocytes, eosinophils, plasma cells and macrophages infiltration, sometimes superficial ulcers.
HD is a developmental abnormality of the neurons of the enteric nervous system (ENS) in the rectum or colon. According to our experimental study, the prominent neuropathological changes are the inner plexus of the intestinal stenosis, and various ENS neurons are missing. (no ganglion cell intestine) or significant absence or dysplasia (small ganglion cell intestine), the synaptic network of the intestinal myenteric plexus (Auerbach plexus) and the submucosal plexus (Meissener plexus) also correspond At the same time, various types of exogenous nerves dominated the widespread disorder. 1 The parasympathetic cholinergic ganglia fibers in the intestinal wall were abnormally hyperplasia, thickening, enzymatic activity, and acetylcholinesterase appeared in the intrinsic membrane. AChE) positive nerve (representing cholinergic nerve), with characteristic changes, and associated with clinical symptoms (degree of obstruction), can be used as an important basis for the diagnosis of this disease, 2 walls containing noradrenaline (NA) Fluorescent sympathetic postganglionic fibers are also increased and thickened, which is characterized by the absence of a normal basket-like plexus synaptic network structure around the lining of the intestinal wall, 3 peptide energy innervation Pan-disorder; the inner wall of the wall is missing any peptide-energy neurons; the substance P (SP) in the intestinal wall, the enkephalin (ENK) fibers are reduced, and the intestinal muscles (muscle space or muscle bundle) And mucosal layer, a large number of thickened vasoactive intestinal polypeptide (VIP), calcitonin gene releted peptide (CGRP), somatostatin (SDM) and neuropeptide Y (neuropeptide Y, NPY) fiber bundle or small nerve trunk or fiber network, NPY dominated overgrowth, but the latter four peptides in the submucosal blood vessels are significantly reduced or missing, 4 contains nitric oxide (NO The neuronal component is altered in the colon segment of the ganglion-free cell, similar to VIP. 5 contains serotonin (5-hydroxytryptamine, 5-TH) neuronal component, at the end of the intestinal plexus without ganglion cells. The nerve fiber bundles in the end mesh and muscle layer are significantly reduced. The changes of the above various neural components in the colon of the disease mainly involve motor neurons, and also have an effect on mucosal secretion and sensory innervation, which may lead to acetylcholine. (acetyl-choline, ACh), SP, ENK, CGRP and NPY (excitatory neurotransmitters, stimulated contractile muscle contraction) and NA, VIP, SOM and NO (inhibitory neurotransmitters, inhibition of intestinal muscle movement) involved in the regulation of the colon The motor dynamic function is out of control, which has become a neurochemical pathophysiological factor in the stenosis of the intestine without ganglion cells.
2. Pathophysiology
The movement mechanism of the colon and internal sphincter is very complicated. The traditional concept is that its innervation is sympathetic and parasympathetic. The former inhibits smooth muscle, ie relaxes; the latter excites smooth muscle, that is, contraction, while the inner sphincter acts. On the contrary, the ganglia in the colon wall is considered to be the parasympathetic nervous system. In recent years, through the pathology, histochemistry, electron microscopy, drug reaction test and animal experiments, it is known that the innervation of the colon and the internal sphincter is divided into three parts. , as already mentioned.
The pathological change of Hirschsprung's disease is due to the absence of ganglion cells in the stenotic segment of the intestine. Okamoto Eiji (1988) confirmed that no connective point (none) between the nerve and the muscle was found in the segment of the diseased intestine, and the neurotransmitter was affected. When quantitatively determined, it was found that the content of both cholinergic receptors or adrenergic receptors was significantly lower than that of normal intestinal segments, resulting in lesional intestinal and internal sphincter spasm stenosis and lack of normal peristaltic function, forming functional intestinal obstruction. The parasympathetic preganglionic fibers that should establish synaptic connections with ganglion cells are proliferated and thickened in the intestines of ganglion-free cells, and the fibers after sympathetic ganglia are also significantly increased. A large amount of acetylcholine is considered to be the main cause of intestinal spasm. One of the reasons is that after the lack of cholinergic ganglion cells, normal segmental movement and rhythmic propulsive peristalsis are blocked, and the parasympathetic nerve from the ankle directly acts on the intestinal wall muscle cells, thus making the diseased intestinal tube persistent. Tonic contraction, in addition, due to the absence of ganglion cells, the hyperplastic sympathetic nerves interrupt the original inhibitory pathway, and can not affect the gallbladder by beta inhibitory receptors. The nerve can produce relaxation of the intestinal wall, but directly reaches the -excited receptor of the smooth muscle to produce sputum. The non-cholinergic non-adrenergic system in the wall also inhibits the neuron deficiency, thus losing the effective relaxation function due to the rectum. The internal sphincter remains in a state of continuous contraction, which causes the normal propulsive wave of the intestine to be blocked. Finally, fecal retention, bloating, and stool can not be discharged. It can be seen that the normal peristaltic wave of the colon cannot be transmitted, and the ganglion cell is not lacking ganglion cells. In particular, the number of sympathetic nerves is also reduced, which is almost completely in a state of no innervation (Cannon's law), leading to ankylosing contracture of the intestines. For a long time, the proximal normal intestinal segment is exhausted and compensatory. The hair expands hypertrophy, and the ganglion cells also undergo degeneration and degeneration until they shrink, so that they decrease or disappear.
Swenson placed the balloon into the colon and recorded the peristalsis of each segment of the intestine. It was found that the normal intestine was completely different from the diseased intestine. The former had a significant increase in contraction when the bowel movement entered the sigmoid colon. In the absence of the ganglion cell, the intestinal peristalsis was transmitted to the sigmoid colon. There is no contraction wave. This phenomenon can explain the constipation and obstruction symptoms of the child. As the age of the sick child increases, the intestinal tube enlarges and constipation progresses progressively, while the secondary lesion has a longer extension. So as to spread to the proximal colon or small intestine.
The result of such long-term chronic obstruction will inevitably lead to poor appetite, nutritional malabsorption, poor growth and development, anemia, hypoproteinemia, etc. After the bacterial flora in the intestines causes dysbacteriosis, the absorption of toxins will cause heart and liver. The kidney function is impaired and finally died due to low resistance to infection or perforation of enteritis.
Prevention
Congenital megacolon prevention
The diagnosis and treatment of congenital megacolon has made great progress in recent years. If children can get early diagnosis and early surgical treatment, the long-term long-term effect is satisfactory, but high. Some children have more stools or incontinence after surgery. It takes a long time to perform defecation training.
Complication
Congenital megacolon complications Complications, intestinal obstruction
Enterocolitis and intestinal perforation are common complications of Hirschsprung's disease, and are the most common cause of death. There are 20% to 50% of cases in children with enterocolitis, and the mortality rate is about 30%. Can occur in all ages, but the incidence of infants is the highest within 3 months, 90% of cases of enteritis occur within 2 years of age, and then gradually reduced, even after radical surgery or colostomy, occasionally colitis Shono reported 61% of postoperative enteritis and more common after Boley surgery. Soaue reported 11.6% of Sweorson's postoperative enteritis, Ikeda reported postoperative enteritis accounted for 33.7%, Soalce after surgery was 19.5%, and Boley after surgery 12.1%. Therefore, postoperative prophylaxis and treatment of enteritis has become an important issue. Some authors have statistics on sputum sputum and then enteritis, and the mortality rate can be reduced. The cause and mechanism of enteritis are still not very clear, and the efficacy has not improved significantly in the past 10 years. Many scholars have suggested that enterocolitis may have the following reasons:
Intestinal obstruction
Swenson first proposed that enteritis was caused by obstruction, no ganglion cell stenosis, lack of peristaltic function, and thus promoted enteritis. Therefore, foreign countries advocated that HD should be diagnosed immediately, but this theory cannot explain the obstruction after ostomy. The release of enteritis still occurs.
Bacterial toxin
In patients with megacolon, stools are detained, bacteria multiply, and flora is dysregulated. In 1986, Thorns et al. used C. difficile antiserum method to examine 13 children with enteritis, 54% of which had bacterial toxins, rather than megacolon. In 12 cases, only 1 case was positive, and 10 cases of Clostridium were isolated from the feces of 13 cases. 77% of these results indicated that Clostridium is closely related to enteritis, due to bacterial toxins. Invading the blood vessels of the intestinal wall, increasing the permeability of blood vessels, a large amount of fluid seeps into the intestinal lumen, causing watery diarrhea, bloating, high heat after the absorption of toxins (39 ~ 40 ° C), sick children and then sepsis, shock failure, DIC, intestine Death by perforation, etc.
3. Allergic reactions
HD enterocolitis, whether it can be operated or not, often fierce, rapid development, and some children even live in the hospital for careful intestinal rehydration, and even sudden death after surgery, so some scholars pointed out These children are due to the hypersensitivity of the intestinal mucosa to certain bacterial antigens, combined with bacterial invasion and sepsis.
4. Local immune function is low
The intestinal mucosal barrier consists of three protective layers:
1 cell pre-protective layer: a physical barrier formed by the secretion of mucus by goblet cells and a microbial barrier formed by normal flora and a protective film formed by secreted lgA;
2 intestinal cell protective layer: composed of intestinal cells and polysaccharide protein complex;
3 post-cell protective layer: composed of connective tissue under the cells, capillaries and lymphatic vessels. In recent years, it has been suggested that local immunological damage is caused by enterocolitis. The Jinjulang study confirmed the number of IgA cells in the colon when it was confirmed by severe colonic colitis. Both the secretion and the secretion amount are significantly reduced and decreased, and the IgA system of the intestinal wall also has a downward trend. The immunoglobulin IgA plays a natural protective membrane role in the intestinal tract, and the double-body IgA can bind to the complement and fix it to the Gram-negative bacillus. The complement system activated by IgA allows lysozyme to digest the mucopolysaccharide on the bacterial wall. Monomeric IgA can also enter the bloodstream from the lamina propria through the lymphatic vessels, and can increase the serum IgA in the intestinal infection. The occurrence of enteritis destroys the normal immune response, which leads to repeated episodes of enteritis. These children are also prone to upper respiratory tract infections when they are low-resistance. Some people also found that the local immunoglobulin-producing cells were significantly lower than the control when studying PL rat enteritis. Group, at the same time found that neutrophil and phosphomucin are depleted and goblet cell mitotic activity is very low, the lack of diseased mice The acid salt may cause sensitivity to bacteria. Teitelbaum also reported that the local immunoglobulin Ig and albumin decreased significantly in the onset of the disease. The above findings may indicate that the occurrence of enteritis is related to local immunity, but these local immune defects It is the primary cause of enteritis, or secondary to enteritis has yet to be further proved.
Colonoscopy occurs when enteritis occurs, mucosal edema, hyperemia and localized mucosal destruction and small ulcers can be seen. Light rubbing is also prone to bleeding. When the lesions are aggravated, the muscle layer develops, and the whole layer of the intestinal wall is edema, congestion, and thickening. In the serosa layer of the giant lesion, yellow fiber membrane coverage is seen. If the lesion is further developed, intestinal perforation can occur, and diffuse peritonitis can be caused. Pathological examination can reveal crypt abscess, degeneration, villous inflammatory cell infiltration and lymphoid follicular hyperplasia. In 1994, Kobayashi used monoclonal antibody to detect intracellular mucomolecules (ICAM-1) to understand its role in HD combined with enteritis. It was found that submucosal vascular epithelium was clearly stained in enteritis, while the control group was rare. By the way, ICAM-1 can induce leukocyte infiltration in many tissues during inflammation, and induce inflammatory hormones such as interferon, interleukin-1 and tumor necrosis factor in various cells, which play a role in adhesion of white blood cells and regulation of extravascular leukocytes. Important, so even before the onset of enteritis or before the onset, if ICAM-1 coloration indicates the risk of enteritis.
In severe cases of enteritis, the child has frequent vomiting, watery diarrhea, high fever and sudden deterioration of the condition, abnormal abdominal swelling and dehydration symptoms, resulting in difficulty breathing, failure, systemic reaction is very poor, although a few children have no diarrhea, when When anal finger examination or insertion into the anal canal, a large amount of strange odorous manure and gas overflow are seen, and the abdominal distension can be reduced. However, it will soon be aggravated. Intestinal colitis is often dangerous, and treatment may cause death if not timely or inappropriate. .
Due to intestinal dilatation, intestinal wall becomes thin and ischemic, intestinal mucosa produces ulcers under the action of bacteria and toxins, bleeding or even perforation forms peritonitis, and enteritis has a higher mortality rate, especially for newborns, up to 70%. ~80%.
5. Water poisoning
Water intoxication is more common in infants and young children. In addition, in the neonatal period, a large amount of hypotonic saline is used to wash the intestines, and the infusion is excessive or too fast. The elderly have congenital megacolon, accompanied by chronic malnutrition, hypoproteinemia, often cellular or Interstitial edema, in the case of improper bowel or infusion, is also prone to water poisoning, acute water poisoning mainly involves the brain, heart, lung, cerebral edema symptoms are nausea, vomiting, coma or convulsions; heart failure or pulmonary edema may also occur In order to prevent water poisoning, the infusion volume should be strictly controlled; the isotonic saline should be used for washing the intestines, and the hypotonic liquid such as soapy water should not be used; the siphon method should not be used to wash the intestines by enema.
Symptom
Congenital megacolon symptoms Common symptoms Congestive frog-shaped abdomen is not discharged, dehydration, bowel, colonic vascular dysplasia, hydrocephalus, loose stool, giant bowel syndrome, loss of appetite
1. Symptoms and signs
(1) Delay in discharge of feces or fetuses: 94% to 98% of newborns who did not receive black fetus in HD24h, Chuanzhong Wusi reported that 97.7% of normal newborns were discharged within 24 hours after birth, and expired infants were 100%. After 24 to 48 hours, the defecation may have organic lesions. Due to the diseased intestinal fistula, meconium cannot pass through the stenosis area, so that a large amount of retention in the sigmoid colon forms bloating, and about 72% need to be treated (plug anal, wash the intestine, etc.) Defecation, after treatment, sometimes the child can maintain defecation function for several days or 1 week, most of the patients have constipation, only a small number of sick children after birth, the fetus is discharged normally, symptoms appear after 1 week or 1 month.
(2) bloating: bloating is one of the early symptoms, accounting for about 87%. In the neonatal period, abdominal distension can suddenly appear, but it can also gradually increase, mainly depending on the obstruction, and the effect of helping defecation in infants and young children is getting more and more effective. Poor, so I have to switch to other methods, and gradually become ineffective, constipation is progressively aggravated, the abdomen gradually bulging, often accompanied by bowel sounds, although you can smell the bowel without a stethoscope, especially at night, sick There may also be diarrhea, or diarrhea, alternating constipation, severe constipation can be several days, even 1 to 2 weeks or longer without defecation, the child is frog-shaped abdomen, accompanied by abdominal wall venous engorgement, sometimes visible intestinal type and Intestinal peristaltic wave, sometimes touched with fecal stone during palpation, until the abdominal circumference of infants is significantly larger than the chest circumference, the length of the abdomen is also greater than the chest, abdominal distension is progressively aggravated like constipation, a large amount of intestinal content, gas retention in the colon, abdominal muscles when the abdominal distension is severe Ascending, affecting breathing, the child is sitting and breathing, and can not sit flat at night.
(3) vomiting: there are not many newborns with HD vomiting, but if they are not treated, the vomiting may gradually increase after the obstruction is aggravated, and even the bile or fecal fluid may be excreted. In infants and young children, the symptoms of low intestinal obstruction are often combined, and in severe cases, vomiting occurs. The content is milk, food, and finally due to intestinal obstruction and dehydration need emergency treatment, after the intestines, infusion and electrolyte supplementation, the condition is relieved, after a period of time, the above symptoms appear again.
(4) intestinal obstruction: Klein statistics of neonatal intestinal obstruction, HD accounted for the second, the first is necrotic enteritis, obstruction is mostly incomplete, and sometimes can develop into complete, neonatal obstruction is not necessarily The length of the ganglion-free intestinal segment is proportional. Martin has seen cases of total colonic ganglion-free cytopathic dysfunction before the age of 1 year. Except for a small number of children with enterocolitis, most children can be relieved after treatment. For a period of time, there is no ganglion cell intestine continuous stenosis, so that the child is incomplete low-level obstruction for a long time. With the aggravation of constipation symptoms and the failure of defecation measures, the condition can be converted into complete intestinal obstruction, and must be immediately Intestinal fistula to relieve symptoms, although individual patients can usually discharge a small amount of loose gas, but there is a huge fecal stone obstruction in the intestine.
(5) Anal finger examination: rectal anal canal diagnosis is crucial for the diagnosis of neonatal megacolon. It can not only detect the presence or absence of rectal anal deformity, but also understand the tension of the internal sphincter, the ampulla of the ampulla and the narrow part. And length, when the fingers are pulled out, due to the expansion and stimulation of the fingers, there is often a large amount of feces, the gas discharge is "explosive", and the bloating is immediately improved. If there is any of the above, the possibility of megacolon should be considered first, and the anal examination during infants and young children. Sometimes the fecal mass can be touched, and when the finger is pulled out, there is a gas and a thin smelly stool.
(6) General conditions: newborns due to repeated low intestinal obstruction, loss of appetite, malnutrition, anemia, poor resistance, frequent respiratory and intestinal infections, such as enteritis, pneumonia, sepsis, intestinal perforation and death, In early childhood, in addition to the above symptoms, the child is chronically hypoproteinemia, poor growth and development, combined with a large number of bacterial reproductive toxins in the intestine, heart, liver, kidney function can be damaged. In severe cases, children with systemic edema, The lower limbs, the scrotum is more pronounced.
2. Clinical classification
The classification of congenital megacolon is quite confusing. Some people use anatomy as the basis. Some people take clinical as the criterion. Some people are classified according to different treatment methods. Even the nouns are the same and the lesions are different. For example, the definition of "short segment type" Some authors predominate that the lesion is confined to the distal rectum, while others believe that the lesion involves the proximal rectum, and the rectum and sigmoid junction are also short segments. For this reason, we refer to the extent of the lesion and the choice of treatment. The clinical and therapeutic predictions are tentatively classified as follows (Figure 1).
(1) Ultra-short segment type: The lesion is confined to the distal rectum, and the clinical manifestation is the internal sphincter achalasia state, and the neonatal stenosis segment is below the shaman line.
(2) Short-segment type: the lesion is located in the proximal and middle rectum, which is equivalent to the second vertebrae, and the distance from the anus is no more than 6cm.
(3) Common type: The ganglion-free cell area extends from the anus to the first atlas, about 9 cm from the anus, and the lesion is located at the junction of the proximal rectum or the rectosigmoid colon, even to the distal end of the sigmoid colon.
(4) long segment type: the lesion extends to the sigmoid colon or descending colon.
(5) Total colon type: the lesion spreads to the entire colon and ileum, within 30 cm from the ileocecal valve.
(6) Total intestinal type: the lesion spreads to the entire colon and ileum, more than 30cm from the ileocecal valve, and even affects the duodenum.
The above classification method is conducive to the choice of treatment methods, and is helpful for the prediction and prognosis of the surgical effect. The common types in the above types account for about 75%, followed by the short segment type, and the whole colon type accounts for 3% to 5%. There are also reports of up to 10%.
3. Combined malformation
Congenital megacolon combined with other malformations is 5% to 19%, domestic Wang reported as 18.9%, and reported as high as 30%, the main malformations are hydrocephalus, congenital, hypothyroidism, intestinal rotation Poor, internal hemorrhoids, rectal anal atresia, cryptorchidism, cleft lip, pulmonary stenosis, clubfoot, hydronephrosis, etc. Among many malformations, the highest incidence of central nervous system malformation, followed by cardiovascular system, urinary system and gastrointestinal tract, In particular, the congenital type accounts for 2% to 3.4%. As for the common cause of central nervous system malformation, it may be due to the low tolerance of nerve cells to harmful environment and at the same time caused by the same factors.
Diagnosis of congenital megacolon, mainly based on clinical manifestations, confirmed X-ray barium enema, rectal anal canal pressure, rectal biopsy, histochemistry and other objective examination methods.
The symptoms of neonatal megacolon need to be differentiated from meconium constipation, intestinal atresia or stenosis, anorectal malformation, etc. After the small finger anus examination, megacolon diseases can discharge feces and gas in large quantities, and the symptoms are relieved. Therefore, Neonatal intestinal obstruction, routine anal examination, not only helps to diagnose and treat neonatal megacolon, but also avoids or reduces false diagnosis and treatment.
For children over 6 months, there are symptoms such as chronic constipation, and there is a history of neonatal megacolon. It is easier to diagnose congenital megacolon, otherwise it is necessary to exclude the megacolon caused by diseases such as anorectal malformation and cretinism. Diet constipation, idiopathic megacolon embolism, anal examination, short-segment congenital megacolon anus tightening, rectum significantly expanding stool or accumulation of gas; common type of congenital megacolon rectal ampulla disappeared, in tightening (not a narrow state), but this state is not constant, the rectum can be passively dilated due to the accumulation of feces, so the congenital megacolon and its classification cannot be diagnosed according to the results of the anal examination. In addition, attention should be paid to congenitality during anal examination. The odor, traits and other characteristics of feces in megacolon diseases.
Once again, it is necessary to do an anal examination for children with congenital megacolon, one is helpful for diagnosis, and the other is for identification.
Examine
Examination of congenital megacolon
Rectal muscle biopsy
Swenson (1955) first used this method, the accuracy rate was 98%. Muscle biopsy from the rectal wall confirmed that the myenteric ganglion cells lacked the diagnosis of congenital megacolon. In theory, it is the most reliable method, but because of some Disadvantages, so it is not necessary at present:
1Smith (1968) found through histological examination that there are developmental and maturation processes in the ganglion cells after birth. The rectal myenteric plexus is especially obvious, and the submucosal plexus is several weeks behind. If not paying attention, the normal child can be diagnosed as congenital megacolon. Or homologous disease,
2 The normal rectum has a low ganglion cell area above the dentate line. In this area, the normal child can be diagnosed as congenital megacolon or homologous disease, so it is emphasized that the height of the material is at least 2 cm above the dentate line. Within 2.5cm, 1-3 years old 3cm, 4 years old and 3.5cm, so short-term megacolon disease is easy to miss diagnosis,
3 pediatric muscle biopsy has intestinal perforation, hemorrhage, infection and other complications, postoperative scar can affect radical surgery, neonatal due to small anal canal, thin rectal wall, inconvenient operation, etc., more prone to complications.
In addition, myometrial biopsy is the main basis for the diagnosis of congenital megacolon homologous disease.
2. Rectal mucosal biopsy
Rectal mucosal biopsy only draws a small piece of mucous membrane. After continuous improvement, the method is simple, safe and reliable. It can be used without anesthesia and without hospitalization. The examination methods include histology, histochemistry and immunohistochemistry. The histological examination mainly uses HE staining to judge nerves. The presence or absence of ganglion cells in the plexus is simple but inaccurate; histochemical examination methods such as acetylcholinesterase require technical conditions such as fresh tissue specimens and cryostats, and acetylcholinesterase activity is low in neonatal period. It is prone to false negative results; immunohistochemistry is highly accurate, but due to the high cost of reagents, it is not suitable for routine diagnosis. Wang Yiping (1991) uses neuron-specific thinning enzyme (NSE) immunohistochemistry. 32 cases of suspected Hirschsprung's disease were diagnosed, and no case was misdiagnosed. Xu Benyuan et al (1995) used NSE and S-100 protein to diagnose Hirschsprung's disease with an accuracy of 100%. NSE is one of the ganglion intracellular enzymes. Is a hallmark of ganglion cells. NSE antibodies bind to NSE in ganglion cells and nerve fibers, making nerve tissue clearly visible, and developing immature ganglion cells. Easy to identify, and easy to distinguish from inflammatory cells, lymphocytes, Schwann cells, macrophages and vascular endothelial cells; S-100 protein is a marker of components around the nervous system, using NSE and S-100 protein The grouping method, the same way, and mutual evidence, especially for the congenital megacolon in the neonatal period, has important diagnostic value. We (1998) applied immunohistochemistry to detect 30 cases of congenital megacolon without nerves. The distribution of P75NGFR in the segmental and normal segments of the intestine is considered to be simple and accurate, and can be used to diagnose congenital megacolon. At present, Tongji Medical University, Shanghai Second Medical University and China Medical University have carried out histochemistry. And immunohistochemistry.
3. X-ray tincture enema
X-ray barium enema is an important basis for judging the extent of the lesion and the choice of surgery. The purpose of the barium enema is to show the segment of the iliac crest and the dilatation segment above it. Therefore, the expansion segment can be confirmed. Do not inject the sputum into the sputum. In order to avoid aggravating the bloating of the sick child and its danger.
The range of the sacral segment is below the descending colon, and the lateral position is the clearest. Therefore, only the lateral radiograph with anal mark is taken. However, when the sigmoid segment reaches the sigmoid colon, it can be comprehensive from the orthotopic position. The diagnostic rate of X-ray barium enema At present, it is still hovering around 90%. There are three main reasons: 1 The diagnosis of neonatal megacolon is difficult. It is generally believed that the morphological changes of the megacolon are not formed until 2 weeks after birth, and some need 3 to 4 weeks or even In a few months, although the functional changes of storage or excretion of expectorant were observed 24 to 48 hours after enema, when the symptoms of obstruction were very serious, the bowel must be digested after enema or surgery, and delayed observation was not allowed; When it is difficult to retain tincture for more than 24h, 2 pairs of short-segment congenital megacolon, especially ultra-short-type congenital megacolon, difficult to distinguish from idiopathic megacolon, 3 pairs of special type of congenital megacolon easily missed diagnosis Or misdiagnosis.
4. Rectal anal pressure measurement
It is an effective method for diagnosing congenital megacolon. It is economical, simple, rapid and safe, and non-invasive, and can be repeatedly tested. The accuracy of the measurement of congenital megacolon by manometry is not reported in the literature (76%~ 100%), the study proves that after injecting 2~3ml of gas into the normal rectal balloon, the anal canal pressure drops rapidly (called normal reflex) within 1~3s, while the congenital megacolon disease injects a lot of gas into the rectal balloon. The anal canal pressure is unchanged (called negative reflex), that is, there is no rectal anal canal reflex or normal reflex. In some children with congenital megacolon, the anal canal pressure does not decrease, but rises (called abnormal reflex) (Fig. 3) Negative reflex and abnormal reflex are collectively referred to as pathological reflex. After detecting 156 cases of chronic constipation, the accuracy of rectal anal canal pressure measurement is 93.33%, of which the misdiagnosis rate is 2.88% (104 cases of pathological reflex, 3 cases except congenital Megacolon: 2 cases were neonates, and were reviewed normally after 6 months; the other case was meconium peritonitis. The rate of missed diagnosis was 7.69% (52 cases with normal reflex and 4 cases with congenital megacolon). In order to improve the accuracy of the pressure measurement diagnosis, it is necessary to note Intention detection method and judgment criteria.
Rectal anal canal pressure diagnosis of neonatal megacolon should be cautious, there are authors to dynamically detect 50 normal newborns, only 13 cases showed normal reflex on the first day after birth, 48 cases (96%) appeared normal within 1 week after birth Reflex, the other 2 cases were not continuously detected due to discharge, and normal reflexes occurred at 100 days and 8 months after birth. In theory, it should be said that neonatal defecation after birth is marked with rectal anal canal reflex, but Pressure measurement observation, we believe that this newly formed or established reflection is not mature and unstable, so it is not easy to display or capture during the test.
It is currently agreed that the most reliable method for diagnosing and identifying ultrashort segments of Hirschsprung's disease and idiopathic megacolon is rectal anal manometry.
Diagnosis
Diagnosis and diagnosis of congenital megacolon
Can be diagnosed based on clinical performance and laboratory tests.
Differential diagnosis
In children with congenital megacolon, acute bowel obstruction occurs in the neonatal period, and it is not uncommon to open an expansive laparotomy; in the elderly, misdiagnosis of fecal stone as a tumor is also occurring; it is often delayed due to atypical symptoms. Diagnosis and treatment, misdiagnosis, and mistreatment are mainly due to unclear medical history and inconspicuous examination. Secondly, there is a lack of understanding and understanding of congenital megacolon. The congenital megacolon must be differentiated from the following conditions.
Neonatal period
(1) Congenital anorectal malformation: This disease is the most common cause of low intestinal obstruction. When anal atresia or only pupil, the abnormal anus can be identified by careful observation, but the anor is normal rectal stenosis or atresia. Also need to be confirmed by anal examination and X-ray examination.
(2) Congenital intestinal atresia or stenosis: low intestinal atresia or stenosis is also a manifestation of low intestinal obstruction. There is no fetus after the anus examination or only a small amount of gray-white jelly-like stool (intestinal stenosis can have a small amount of feces), X-ray tincture The enema shows that the distal colon of the lesion is abnormally small (fetal colon), and the expectorant cannot pass through the lesion (latching) or difficult to pass (stenosis) the lesion.
(3) Functional intestinal obstruction: functional intestinal obstruction is common in premature infants, Nixon et al (1968) by rectal anal canal pressure test for such children, proved lack of normal reflex, thought to be related to immature cells of intermuscular ganglion cells Other diseases can also cause functional intestinal obstruction in newborns, such as dyspnea, infection, and brain tissue damage.
(4) necrotizing enterocolitis: neonatal necrotizing enterocolitis, more related to postnatal asphyxia, hypoxia, shock and other reasons, in addition to no history of constipation after birth, clinical symptoms are often not easy with neonatal colitis Identification.
(5) Meconium peritonitis: meconium peritonitis is associated with fetal perforation in the fetus, perforation is not closed before birth, perforating peritonitis occurs after birth due to intestinal contents entering the abdominal cavity; perforation has been healed before birth, sterile After the fetus enters the abdominal cavity, it causes meconium peritonitis, which causes extensive adhesion of the small intestine and calcification of the fetus, and adhesive intestinal obstruction may occur.
(6) simple meconium constipation: simple meconium constipation is also called meconium plug syndrome, mainly because the fetus is sticky, causing a transient fetus discharge disorder, resulting in intestinal obstruction, such diseases are full-term newborns, After 24 to 48 hours after birth, it can not be automatically excreted, and there is a symptom of low intestinal obstruction. After the bowel movement by means of anal examination or bowel washing, the symptoms are relieved and no recurrence occurs.
(7) Meconium intestinal obstruction: Meconium intestinal obstruction is rare in China. It is associated with fibrocystic disease of the pancreas and is one of the common causes of low intestinal obstruction in neonates in Western countries. The incidence rate is about 1/2000. In the disease, 10% to 15% of the sick children are overly sticky due to the fetus and block the distal ileum.
(8) neonatal peritonitis: also divided into primary peritonitis and recurrent peritonitis, neonatal primary peritonitis is rare, mostly umbilical infection, and some are blood-borne, associated with sepsis, secondary peritonitis Neonatal megacolon perforation, gastric perforation, biliary perforation and appendicitis.
2. Infants and children
(1) continuation of megacolon: also known as organic megacolon, megacolon continues in organic lesions or mechanical insufficiency, associated with long-term defecation or obstruction, common in congenital anorectal stenosis, rectum External mass compression, anal scar formation after anal rectal malformation or trauma, can be diagnosed by anal examination.
(2) idiopathic megacolon: the disease is related to improper bowel movement training, characterized by no history of constipation in the neonatal period, when there is a morbidity or obvious symptoms at 2 to 3 years old; chronic constipation is often accompanied by anal sputum, often with abdominal pain The rectal sensation is in addition to the rectal dilatation, the sphincter is in a state of tension, and the rectal anal canal pressure has a normal reflex, which is the most reliable method for diagnosing the disease and excluding Hirschsprung's disease.
(3) Congenital megacolon homologous disease.
(4) Congenital sigmoid colon is too long: due to the sigmoid colon is too long and a large amount of feces caused by chronic constipation, often accompanied by sigmoid colon expansion.
(5) degenerative smooth muscle disease: its symptoms are constipation, chronic progressive bloating and intestinal obstruction, in addition to colonic dilatation, there is also small intestine dilatation and even the stomach, esophageal dilatation, rectal anal manometry can be seen with normal reflex, thinning of the intestinal tube, Degeneration and necrosis of muscle cells and muscle fiber regeneration, and inflammatory lesions, ganglion cells and plexus displacement.
(6) Constipation for other reasons:
1 Diet constipation: infants and young children may be due to insufficient breast milk, milk substitutes are too thick or scarce, or food supplements are not added in time; older children are too little or too fine, and eat less cellulose-rich vegetables and fruits. To.
2 neuropathic constipation: caused by defects in the development of the central nervous system, such as brain hypoplasia, microcephaly, cerebral palsy and spinal cord hernia.
3 endocrine constipation: when the thyroid is low-power, due to weakened gastrointestinal motility, abdominal distension, constipation, and progressive aggravation in the neonatal period, the disease is characterized by mental retardation, facial swelling, nasal bridge wide, muscle tension Low, basal metabolic rate and serum protein combined with reduced iodine can be diagnosed, hyperthyroidism, pheochromocytoma can also have chronic constipation and colonic expansion.
4 vitamin deficiency: vitamin B1 deficiency can destroy the ganglion cells in the intestinal wall, causing constipation.
5 drug constipation: children with chronic or large doses of the following drugs can cause chronic constipation: methylphenidate hydrochloride (central stimulant), diphenylhydantoin (phenytoin), imipramine hydrochloride (antidepressant), Antacids and drugs containing Codein.
