congenital malrotation
Introduction
Introduction to congenital intestinal malrotation Congenitalintestinal malrotation (congenitalintestinalmalrotation) is due to the instability of the intestinal rotation during embryonic development, that is, the rotation of the superior mesenteric artery as the axis is incomplete or abnormal, causing the intestinal position to mutate and the mesenteric adhesion is incomplete, thereby causing intestinal obstruction or Intestinal torsion. basic knowledge The proportion of illness: 0.02% Susceptible people: seen in newborns Mode of infection: non-infectious Complications: intestinal obstruction, volvulus
Cause
Causes of congenital intestinal malrotation
(1) Causes of the disease
The early intestine of the embryo is a tube and has a common mesentery. The embryos are 6 to 10 weeks old. Because the midgut develops very fast, it cannot be accommodated in the slower abdominal cavity, but is pushed by the rapidly growing liver. The intestine passes through the umbilical ring into the yolk sac to form a physiological umbilical hernia. By the 10th to 11th week of the embryo, the development of the abdominal cavity is accelerated, the volume is increased, the midgut is returned to the abdominal cavity, and the superior mesenteric artery is the axis. Rotate 270° counterclockwise to make the duodenal jejunum from right to left, from the superior mesenteric artery to the left side, forming the duodenal suspensory ligament, and the ileal colon junction from left to right in the mesentery The upper artery is turned to the right upper abdomen and then gradually reduced to the right axilla. After normal rotation is completed, the transverse colon is located in front of the superior mesenteric artery. The ascending colon and descending colon are attached to the posterior wall of the abdomen by the mesenteric membrane. The abdomen is oblique to the right lower abdomen and attached to the posterior wall of the abdomen.
In recent years, a schematic description of the original Snyder and Chaffin has been cited. The midgut is divided into two parts: the duodenal jejunum and the ileal colon. The rotation of the former is the upper side of the superior mesenteric artery, which is rotated counterclockwise. 90° reaches the lower right, then 90° to the rear of the artery, and finally 90° to the left side of the artery to form the duodenal suspensory ligament, the same is true for the rotation of the latter. The intestinal tract is located at the lower left of the artery. After three times of 90° counterclockwise rotation for a total of 270°, the transverse colon is located in front of the artery, the cecum is moved to the right upper abdomen, and then gradually descends to the right lower abdomen, accompanied by the rotation of the intestine, in the last stage, the mesentery of the midgut Fusion with the posterior abdominal wall, the root of the mesentery from the flexural ligament obliquely to the right lower abdomen cecum, so the duodenum, cecum and ascending colon are fixed, the small mesentery has a fairly wide base attached to the posterior peritoneum, In this normal anatomical condition, the midgut is not easily twisted.
(two) pathogenesis
If the normal rotation of the intestine occurs, obstacles or abnormalities occur at any stage, abnormal intestinal position will occur, and various types of intestinal obstruction may occur. The types of intestinal dysplasia during embryonic period are:
1. The midgut is not rotated: the midgut does not rotate to any extent in the counterclockwise direction when the abdominal cavity is retracted. The small intestine and the colon are hung on the common mesentery. The mesenteric root is arranged in the sagittal plane in front of the spine, often accompanied by the umbilical cord. Bulging and abdominal fissure deformity.
2. Incomplete rotation of the intestine: the intestinal fistula is rotated 90° and then stopped. The small intestine is suspended on the right side of the abdominal cavity. The cecum and proximal colon are located on the left side of the abdominal cavity. The appendix is located in the left lower abdomen. It is a common abnormal rotation. The lower part of the duodenum is located in the mesentery. On the right side of the root, there is no duodenal jejunum, the ascending colon is in front of the spine or on the left side, and the duodenum, small intestine and colon are suspended from the common free mesentery.
3. Intestinal malrotation type I: The intestinal fistula is rotated 180° and then stopped. The lower part of the duodenum is behind the mesenteric root. The cecum and ascending colon are located in the midline of the abdomen, and there is a flaky peritoneal adhesion or cord, spanning the twelve fingers. The front part of the second part of the intestine is attached to the posterior wall of the right abdomen. When the proximal colon develops, the cecum is on the right side of the spine in front of the duodenum, compressing the duodenum or forming a high cecum.
4. Intestinal malrotation type II: This type is the reverse rotation of the duodenum, and its abnormal rotation process is complicated, so there are many kinds of deformed manifestations. At the beginning, the proximal end of the midgut is rotated 90o in the normal counterclockwise direction and no longer in the original direction. Rotating, abnormally turning clockwise from right to left back 90 ° ~ 180 °, so that the duodenal jejunum stays in front of the superior mesenteric artery instead of the normal rear, while the ileum cecum at the distal end of the midgut is right The lateral shift line is located in the upper right abdomen before the duodenum forms a high cecum. If the ileum cecum continues to advance to the right lower abdomen, the small intestine and mesenteric vessels are all wrapped in the proximal mesenteric membrane to form the colonic mesentery, and the ascending mesentery constitutes a hernia. Small bowel obstruction may occur due to compression of the sac of the capsule or compression of the small intestine of the capsule.
5. Reverse rotation of the intestine: the midgut rotates 180° clockwise in the abnormal shape of the type II, causing the duodenal jejunum to be in front of the superior mesenteric artery, while the proximal end of the colon rotates clockwise to the superior mesenteric artery and the mesorectum. Later, the cecum continues to travel to the right lower abdomen, causing the middle part of the transverse colon to stay behind the artery, and then the transverse colon obstruction occurs. If the proximal end of the midgut continues to rotate 180° clockwise in the direction of the superior mesenteric artery, the duodenum jejunum is made. The curve moves to the left posterior superior mesenteric artery, at which point the cecum migrates and stays in the left abdominal cavity.
6. The total mesentery of the small intestine: the ascending mesentery does not adhere to the posterior wall of the abdomen is a combined abnormality of the rotation of the midgut. It can also be a symptom of normal intestinal rotation, or coexist with the poor rotation of the intestine. At this time, the twelve fingers The inferior part of the intestine is located behind the superior mesenteric artery. The duodenum is located on the left side of the abdomen. The mesenteric root is formed by the small mesenteric shape of the mesentery. It protrudes from the lower part of the pancreas and is fan-shaped. The ascending colon is close to the right abdominal wall, but there is no adhesion. If the ascending mesentery partially adheres to the posterior abdominal wall, the cecum is released from the adjacent ascending colon.
Combined malformation: 30% to 62%, half of the duodenal atresia, other jejunal atresia, congenital megacolon, mesenteric cyst and so on.
7. Abnormal rotation of the stomach and duodenum: Because the reverse rotation of the stomach umbilical hernia is reversed or abnormally rotated with the reverse stomach, this type is often accompanied by cardiac malformations such as tetralogy of Fallot, three-chamber heart or arteries. dry.
Prevention
Congenital intestinal malrotation prevention
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.
Complication
Congenital intestinal malrotation complications Complications, intestinal obstruction, intestinal torsion
Due to the complicated process of intestinal rotation abnormality, a variety of pathological manifestations and complications are caused, and the incidence rate is described as follows.
1. Peritoneal cord compression of the duodenum: When the ileum cecum is blocked, the cecum stays in the right upper abdomen, below the stomach or in the left upper abdomen, the membranous connective tissue is called the ladd band by the cecum and ascending colon. Crossing the second or third part of the duodenum to the right posterior abdominal wall, causing compression of the duodenum, sometimes the cecum itself is fixed in front of the duodenum, clinically manifested as duodenal complete Sexual or incomplete intestinal obstruction, the peritoneal cord is present in all patients with poor intestinal rotation.
2. Intestinal torsion: more than half of the small intestine or midgut can be twisted. Because the small intestine, cecum and ascending mesenteric membrane do not adhere, only the superior mesenteric artery root is connected to the posterior abdominal wall with a narrow mesangial stalk. On the mesangial root, the intestine can easily twist clockwise around the mesothelial stalk (ie, reverse the direction of normal rotational motion), resulting in acute high intestinal obstruction, the degree of intestinal torsion varies from 360 ° to 720 °, multiple circles and tight The torsion causes mesenteric vascular infarction and intestinal necrosis.
3. Proximal membranous adhesion of the jejunum: Where the rotation of the duodenal jejunum is blocked, and the duodenum stays in front of or to the right side of the superior mesenteric artery, it can be seen that the membranous tissue at the beginning of the jejunum is entangled with the membranous tissue to make the jejun twisted and obstructed. .
Symptom
Congenital intestinal dysfunction symptoms Common symptoms Constipation bloody abdominal pain Gastrointestinal symptoms Peritonitis Intestinal atresia Shock High fever dehydration Frequent vomiting and constipation
Intestinal malrotation is one of the more common causes of neonatal intestinal obstruction. In the digestive tract malformation, the disease is only slightly less than hypertrophic pyloric stenosis. At this point, China is very different from European and American countries. In these countries, hypertrophic pyloric stenosis is better than Intestinal dysplasia is more than 10 times more, but not all patients with pathology of intestinal rotation have symptoms in the neonatal period. In infants and children, occasionally this case can be encountered. Very few can also occur in adults. Malady often leads to the following clinical manifestations: 1 intestinal torsion; 2 acute or chronic duodenal obstruction; 3 intra-abdominal spasm, age at onset, more neonates, accounting for 80% of cases, some cases in children or adults There are symptoms, and there are a few cases with no clinical symptoms, which are occasionally found during X-ray or other operations.
1. Neonatal intestinal malrotation: normal meconium is discharged within 24 hours after birth, and the initial feeding is also good. Generally, a large amount of biliary vomiting suddenly occurs on the 3rd to 5th day. Due to the different degrees of duodenal compression, Partial or complete obstruction, partial obstruction, intermittent vomiting, vomit with bile, abdominal dissatisfaction, no positive signs, complete obstruction, vomiting continued and frequent, accompanied by dehydration, weight loss and constipation, if concurrent Intestinal torsion, the symptoms are more serious, vomiting coffee liquid or hematemesis, blood in the stool, suggesting that intestinal narrowing has occurred, intestinal necrosis or perforation may occur with toxic shock symptoms such as peritonitis, high fever, dehydration.
About 20% of cases of neonatal intestinal malrotation may be associated with jaundice, the reason is not clear, may be caused by dilated stomach and duodenal compression of the common bile duct caused by obstructive jaundice; or due to portal vein and mesenteric vein compression, blood The flow rate is reduced, and the hepatic arterial blood flow is compensated to increase, so that the untreated indirect bilirubin is returned to the circulation. At the same time, due to the decrease of portal blood flow, the hepatocyte hypoxia and the formation of the enzyme system are affected.
2. Infant and child intestinal malrotation: due to different pathological malformations, it is manifested as varying degrees of intestinal obstruction symptoms, most of which are intermittent bile-containing vomiting, and often can relieve themselves, so repeated attacks, there are a few The child has been asymptomatic since birth, severe abdominal pain due to sudden bowel rotation, frequent vomiting and constipation and other symptoms of complete intestinal obstruction. In addition, due to repeated episodes of partial intestinal obstruction, intestinal ischemia occurs, thereby affecting the intestine It is reported that 70% of infants and children have malnutrition in the absorption and transport of nutrients by the mucosa. Therefore, it is suggested that children with growth and developmental disorders and gastrointestinal symptoms must be used as gastrointestinal tract. X-ray examination to rule out poor intestinal rotation.
All newborns have high intestinal obstruction, and those who have had normal meconium discharge should consider the diagnosis of poor intestinal rotation, neonatal intestinal malrotation and duodenal atresia or stenosis, and the clinical symptoms of the annular pancreas are similar. There is a possibility of coexistence, it is quite difficult to identify, so as long as there is a clear presence of duodenal obstruction, it should not be too much, and should be explored as soon as possible.
Examine
Examination of congenital intestinal malrotation
X-ray inspection
(1) Abdominal erect plain film: Newborns can show enlargement of the stomach and duodenum or double-bubble sign, the gas content in the small intestine is reduced, the intestinal lumen is obviously dilated with a stepped liquid level, suggesting that the intestinal obstruction or intestinal necrosis may be .
(2) barium enema examination: the traditional barium enema examination showed that the abnormal position of the cecum or colon is the X-ray feature of the disease.
1 intestinal rotation abnormality type I and type II: the cecum is located under the liver, in front of the duodenum, below the stomach or left quarter ribs, sometimes the cecum bypasses the right upper abdomen and folds back to stay in the left quarter rib.
2 The intestine does not rotate: all or most of the colon is in the left abdominal cavity and overlaps each other. The cecum is in the left lower abdomen. The ileum enters the cecum in the direction from right to left. When the appendix is developed, it hangs from the right side of the cecum.
3 Intestinal reverse rotation: The tincture shows a zigzag or zipper-like external pressure stenosis through the middle of the transverse colon. The colon at both ends of the stenosis can maintain normal morphology or hepatic flexion and ascending colon expansion. Sometimes the entire colon is particularly long or the right colon is free.
4 The position of the cecum is normal and does not rule out intestinal malrotation: patients with poor intestinal rotation may show the cecum in the normal position. This is because the duodenal jejunal movement is frustrated, while the ileal cecum is still rotating normally, and the cecum is in a normal position. In some cases, the cecum and ascending colon are free. When the barium enema is injected into the cecum, the cecum enters the right axilla. When this happens, the diagnosis should not be further examined.
(3) Upper gastrointestinal angiography: There are abnormal duodenum or duodenal jejunum and jejunum position in the small intestine dysplasia. Upper gastrointestinal angiography is more diagnostic value. Neonates should use lipiodol angiography, Torres (1993 The upper gastrointestinal angiography is considered to have a sensitivity rate of 95% for diagnosis of intestinal malrotation, and the diagnosis rate is 86%. Neonatal upper gastrointestinal angiography can also detect duodenal coexistence malformation. When examining, the contrast agent or expectorant should be observed through the twelve fingers. The intestines are not missed until the entire jejunum is examined. The angiographic examination may have the following manifestations.
1 duodenal abnormality: A. Duodenum part 2 or part 3 shows external pressure stenosis, expectorant through slow or retention, stomach and duodenum first expansion; B. duodenum The third horizontal line and the fourth part disappeared.
2 The duodenal jejunum is shifted to the front of the spine or the right side of the spine: the third part of the duodenum moves straight down to the beginning of the jejunum, so the duodenal jejunum disappears and the jejunum begins to spirally twist ( Corkscrew) suggests a small bowel twist.
3 All small intestines are located on the right side of the abdominal cavity.
2. B-ultrasound examination of abdominal B-ultrasound, the positioning of the superior mesenteric artery and vein has important diagnostic value for the disease. The midgut of the embryonic period is rotated by the superior mesenterica arteries (SMA) as the axis. The position of the artery is constant, and the superior mesenterica vena (SMV) rotates with the midgut and sweeps across the horizontal plane of the lower edge of the pancreas. It shows a normal B ultrasound image. It can be seen that the SMA is located behind the pancreas and the anterior side of the abdominal aorta. A circular sound image, and the SMV is oval in the right front of the SMA, the anterior side of the inferior vena cava. When there is a poor rotation of the small intestine, the B-ultrasound shows that the SMV is not in front of the inferior vena cava, but is displaced to the abdominal aorta. Front side, directly in front of the SMA or left front.
This method was first reported by Gaines (1987). Ahmad (1993) performed B-ultrasound examination on 19 cases of intestinal malrotation before operation. All showed superior mesenteric vein displacement, 18 cases of SMV were displaced to the left front of SMA, and 1 case was shifted to In the front of the artery, all 19 cases were confirmed by surgery. However, only 9 cases were diagnosed as intestinal malrotation after routine X-ray examination. Ahmad also used 20 other digestive tract diseases as controls. All showed normal SMV position.
3. CT and MRI diagnosis CT and MRI are similar to B-mode ultrasound in the mesenteric vascularization. Nichols and Li (1983) performed pancreatic CT examination on 3 adult patients with misdiagnosed chronic pancreatitis, and found that the left renal vein entered the lower cavity. When the venous level was swept, it was clearly shown that the SMV was rotated to the left anterior side of the SMA, called the superior mesenteric vein rotation sign. These three cases were confirmed by X-ray examination as intestinal malrotation, and then Shatzkes et al. (1990) performed CT on other adult cases. And MRI examinations have the same conclusion.
Diagnosis
Diagnosis and diagnosis of congenital intestinal malrotation
Infants and children have atypical symptoms, so they often rely on X-ray examination to confirm the diagnosis, including abdominal erect flat film, barium enema as the main diagnostic basis, larger infants and children can be swallowed in the case of incomplete duodenal obstruction Take a small amount of dilute or lipiodol for inspection.
The disease is similar to the duodenal atresia or stenosis, and the clinical symptoms of the annular pancreas are similar, and there is a possibility of coexistence.
