Intestinal malrotation in children

Introduction to pediatric intestinal malrotation Intestinal dysplasia refers to a disorder in which the rotation of the intestine and the superior mesenteric artery in the embryonic stage is caused by the rotational movement of the axis, resulting in a change in the position of the intestine and incomplete adhesion of the mesentery. It is a congenital disease that easily causes intestinal obstruction. The anatomical abnormalities caused by disturbances in the development of the small intestine and can be life-threatening, mostly in infants and children. basic knowledge Sickness ratio: 0.0001% Susceptible people: young children Mode of infection: non-infectious Complications: congenital diaphragmatic umbilical bulging abdominal fissure anal atresia congenital heart disease septic shock malnutrition

Causes of intestinal malrotation in children

(1) Causes of the disease

Understanding the development of small intestine embryos is of great significance for understanding and surgical treatment of the disease.

In the first trimester, the development of the embryonic midgut is faster than the development of the body cavity. Therefore, when the fetus develops to the 4th week, the midgut usually protrudes into the abdominal cavity and forms the umbilical hernia. About 10 weeks after the pregnancy, the intestine segment is incorporated into the abdominal cavity, and the rotation and fixation are gradually completed. Until the final form of the small intestine and colon of the full moon, if the midgut is disturbed during the rotation, the corresponding clinical symptoms may occur after birth, and the midgut development is divided into three stages.

First stage

The umbilical hernia is formed. At 4 weeks of gestation, the midgut of the fetus begins to bend to the ventral side and enters the pedicle cavity to form the hernia. The central axis of the iliac is the superior mesenteric artery (SMA), and the midgut is divided into the head. The lateral segment (before the artery, the duodenal jejunum segment) and the caudal segment (the posterior artery, the blind colon segment), the first stage of the midgut is faster than the caudal segment.

(1) development of the head side segment: the midgut tendon is formed, and during the growth process outside the body cavity, the head side segment is pushed downward by the developing liver and the left umbilical vein, and rotated 90° counterclockwise to the right side of the SMA; The intestine cavity is further developed. Before the start of the second phase, the head side segment is rotated 90° to the rear of the SMA for a total rotation of 180°.

(2) Development of the caudal segment: In the first stage, the caudal side segment of the midgut rotates in parallel with the head segment, and the ileocecal portion is initially located under the SMA, synchronized with the head side segment for the first 90° rotation to the right side of the SMA, and the ileocecal portion Rotate 90° counterclockwise to the left side of the SMA as shown in Figure 2B. Before the 10th week is included in the abdominal cavity, the ileocecal zone continues to rotate 90°, which is just below the SMA ventral side.

2. The second stage of the midgut is incorporated into the abdomen.

(1) Development of the head side segment: The intestine segment continues to develop. At 10 weeks of gestation (at this time, the embryo length is about 40 mm), it begins to return to the abdominal cavity, and is completed by 11 weeks of gestation. The head side segment is first returned, and the SMA continues to rotate 90°. A total of 270° counterclockwise rotation. Finally, the duodenal jejunum junction was fixed to the posterior abdominal wall on the left side of the SMA via the flexor ligament.

(2) Development of the caudal segment: During the process of the abdominal colon back into the abdominal cavity, it also continues to rotate 90° to the right side of the SMA, and rotates 270° counterclockwise around the SMA.

3. The third stage

The midgut is fixed from 12 weeks of gestation to birth. If the midgut rotates normally, the colon is gradually fixed. The peritoneal banding-like tissue is ascending, and the descending mesenteric membrane is attached to the posterior abdominal wall. If the cecum and ascending colon rotate incompletely, it does not reach the right. In the flank, the peritoneal band still connects the ascending colon to the right colonic sulcus, and the band spans across the ventral side of the duodenum, which forces the intestine to cause obstruction.

(two) pathogenesis

The abnormal anatomical abnormalities are mainly classified according to the head side and the tail side. Fixation abnormalities usually only occur in the blind colon.

1. Not rotating at all

The most common clinically, the midgut does not rotate at all, that is, the head side and the tail side do not rotate as shown in Figure 4. Under normal circumstances, the duodenum rotates to the rear of the SMA, and the ligament of the flexor is just to the left of the midline. Gastrointestinal level, if the midgut does not rotate, the length of the duodenum becomes shorter, the appearance is spiral, completely located on the right side of the midline, leading to duodenal insufficiency obstruction; and the intestine segment is not fixed, making the midgut susceptible to twisting, The mesentery of the duodenum and colon is fused to each other to form a mesangial pedicle. The midgut is twisted by this axis. Under normal circumstances, the base of the small mesentery is wide, from the left upper abdomen to the right ligament. In the lower ileocecal ileus, axial reversal is generally not possible in the small intestine and mesentery; if the proximal jejunum and distal ileum are located in the mid-abdomen and the mesenteric attachment is relatively narrow, the possibility of torsion is greatly increased.

2. Head side rotation abnormal

If only the head side segment does not rotate, and the tail side segment is rotated and fixed normally, it may also be caused by duodenal obstruction due to compression of the mesenteric band, but due to duodenal jejunum connection to ileocecal The mesangial attachment between the two is still relatively broad, and the possibility of torsion of the midgut is small.

3. The head side section rotates in the opposite direction

Causes the duodenum to be in front of the SMA (normally located at the rear); and the reverse rotation of the caudal segment causes the transverse colon to be behind the SAM. As shown in Figure 6, there is a colonic obstruction. If the caudal segment rotates normally, with the ascending colon from the upper left The abdomen is rotated to the right lower abdomen, and the mesentery spans the front of the SMA, covering the small intestine developed from the lateral part of the head, forming a hernia sac, called the duodenal paralysis.

4. The head side section does not rotate completely

Causes the duodenal jejunum junction (the ligamentous ligament) to be lower than the normal position of the left upper abdomen; and the abnormal rotation of the caudal segment can cause the midgut to twist, and in addition, the head side segment is not rotated or incompletely rotated, Objective criteria, it is generally believed that as long as the ligament of the flexor is located on the right side of the midline of the abdomen, it does not rotate.

5. The rotation of the tail section is abnormal.

If the rotation of the head side is normal, but the rotation of the tail side is abnormal, it can also cause the midgut to be twisted, which is the same as the complete rotation. At this time, the attachment of the mesenteric root between the ligament and the ileocecal part is narrow.

6. The tail side segment does not rotate completely

It may lead to abnormal colonic fixation, incomplete fixation of the ileocecal area may cause cecal torsion; and when the colonic hepatic curvature is incomplete, there is a peritoneal band extending from the colon to the upper right posterior abdominal wall, resulting in partial obstruction of the duodenum.

Prevention of pediatric intestinal malrotation

Preventive measures and other birth-defective diseases, birth defects are important factors affecting the health of infants and children, affecting the quality of the birth population. To this end, the multi-disciplinary and multi-disciplinary collaboration system is formed to reduce and reverse the incidence of neonatal birth defects. Prevention should be carried out from pre-pregnancy to prenatal:

1. Premarital medical examination plays an active role in preventing birth defects

The size of the effect depends on the examination items and content, mainly including serological tests (such as hepatitis B virus, Treponema pallidum, HIV), reproductive system tests (such as screening for cervical inflammation), general physical examination (such as blood pressure, electrocardiogram), and asking about family history of the disease. , personal past medical history, etc., do a good job in genetic disease counseling.

2. Pregnant women avoid harmful factors as much as possible

Including away from smoke, alcohol, drugs, radiation, pesticides, noise, volatile harmful gases, toxic and harmful heavy metals, etc., in the process of antenatal care during pregnancy, systematic screening of birth defects, including regular ultrasound, serology Screening, etc., if necessary, a chromosome check.

Once an abnormal result occurs, it is necessary to determine whether to terminate the pregnancy; the safety of the fetus in the uterus; whether there is sequelae after birth, whether it can be treated, how to prognose, etc., and take practical measures for diagnosis and treatment.

Pediatric intestinal dysplasia complications Complications congenital umbilical umbilical bulging abdominal fissure anal atresia congenital heart disease septic shock malnutrition

Comorbidity

Non-rotation or insufficiency of the midgut is often an important complication of congenital diaphragmatic and abdominal wall defects - umbilical bulging and abdominal fissure. It is reported that 30% to 62% of children with poor rotation have malformations, mostly digestive tract. Malformation, 1/2 duodenal atresia, 1/3 of patients with ileal atresia with intestinal malrotation, one of the reasons is that intrauterine intestine torsion causes obstruction of mesenteric blood supply, leading to intestinal atresia, other malformations include: Meike Diverticulum, duodenal valve or stenosis, megacolon, anal atresia, esophageal atresia with esophageal tracheal fistula, congenital short bowel, biliary atresia, congenital heart disease, visceral inversion, mesenteric cyst and piriform abdominal syndrome, It has been reported that familial intestinal malrotation associated with facial or limb abnormalities suggests that the disease may be related to heredity.

2. This disease can occur dehydration, acidosis, septic shock, peritonitis, strangulated intestinal obstruction, such as intermittent symptoms can cause malnutrition, growth retardation.

Pediatric intestinal dysfunction symptoms Common symptoms Anorexia abdominal pain Chronic abdominal pain Abdominal distension Peritonitis Thrombocytopenia Leukocytosis Diarrhea Black stool dehydration

Poor rotation can be expressed as: 1 midgut torsion, 2 duodenal insufficiency or complete obstruction, bilious vomiting, 3 intermittent or long-term abdominal pain, intermittent diarrhea or blood in the stool, 4 asymptomatically found by chance, in addition to Weight loss or growth dysplasia, most of the sick children within 1 year of age, but also can be asymptomatic after adulthood, before the definition of other diseases, biliary vomiting should be considered first in children under 1 year of age.

1. Midgut volvulus

Midgut torsion is more common in infants and children, but it can also occur in other age groups, even in adulthood. It is a surgical emergency. If it is not treated in time, it can cause short bowel and death due to small intestinal necrosis. The typical symptoms are neonatal Bile vomiting, vomiting is still associated with duodenal angulation and peritoneal ligament compression leading to duodenal obstruction, intestinal obstruction, sepsis, hemorrhagic intracranial hypertension can also cause bilious vomiting, need to quickly make a differential diagnosis The midgut torsion is currently unable to predict when or under what circumstances, so children with bilious vomiting must be actively treated and treated, and should not be allowed to observe until they develop strangulated intestinal obstruction. Necrosis, the chance of survival is greatly reduced, and it is extremely difficult to retain the small intestine with sufficient length. Therefore, if there is a poor rotation, it should be corrected.

In addition to biliary vomiting, children may have abdominal distension, dehydration, irritation, etc.; children with strangulated intestinal obstruction are consciously indifferent, septic shock; other clinical manifestations include: abdominal wall flushing, peritonitis, acidosis, thrombocytopenia, white blood cells Increase or decrease, as well as intestinal bleeding and/or melena from ischemia of the intestinal mucosa.

Intermittent torso can also have intermittent symptoms, mainly seen in elderly children, including chronic abdominal pain, intermittent vomiting (sometimes non-biliary), anorexia, weight loss, growth and development, intestinal malabsorption, diarrhea, etc. Intestinal partial torsion of the mesenteric vein and lymphatic drainage blocked, can cause nutrient absorption disorder, protein loss in the intestinal lumen; arterial insufficiency caused by mucus ischemia, black stool.

2. Duodenal obstruction

The duodenal jejunum of the duodenal obstruction is not rotated or rotated around the SMA, causing the duodenum to fold, twist, and produce intermittent obstruction. In addition, the ascending colon is passed through the duodenum. The congenital band of the right upper and lower abdominal wall can compress the duodenum, causing obstruction. Typical symptoms are bilious vomiting (occasionally non-biliary) and abdominal pain, or both.

3. Intermittent chronic abdominal pain

Patients with poor rotation may have intermittent or chronic abdominal pain for a variety of reasons, and often coexist. Intermittent volvulus or other causes of intestinal obstruction can cause dilatation of the intestine, causing spasm and vomiting; mesenteric vein or lymphatic system partially or Intermittent occlusion can cause intestinal wall, mesenteric and mesenteric lymph node edema, the above reasons can also cause abdominal pain, partial torsion can also cause chronic arterial insufficiency, leading to diarrhea, chronic abdominal pain, postprandial aggravation of intestinal colic, or lack of mucosa The blood appears black.

4. Asymptomatic patients

When abdominal surgery or upper and lower gastrointestinal angiography is performed for other diseases, the asymptomatic intestinal malrotation may be found. The pathological basis may be that the head side and the tail side do not rotate at all, or the head side may rotate normally. The side segments do not rotate.

Pediatric intestinal malrotation check

Blood tests for peripheral blood may have leukocytosis or decrease, thrombocytopenia; blood biochemical tests may have metabolic acidosis, etc., stool examination occult blood positive.

1. Abdominal plain film

Every newborn with bilious vomiting should be immediately examined by imaging, usually in the anterior and posterior vertical and lateral abdominal plain films. The imaging findings of the midgut torsion are:

(1) Obstruction of the gastric outlet, visible dilated gastric vesicles, reduced distal gas.

(2) The typical double bubble sign suggests duodenal obstruction.

However, the above two situations are rare. The baby vomits bile-like substances. Even if the abdominal plain film is normal, the intestinal rotation cannot be ruled out. It is necessary to further check the diagnosis. The intestinal flat cavity of the midgut torsion patient can be completely normal. It can also be manifested as complete small bowel obstruction, including multiple inflated dilated intestinal fistulas and fluid level. At this time, there may be intestinal necrosis. If the abdominal plain film indicates intestinal obstruction, no further examination is needed, and surgery should be performed immediately.

2. Upper gastrointestinal angiography

When it is suspected that there is poor intestinal rotation, routine gastrointestinal angiography should be performed. The best sputum angiography can be used. Water-soluble contrast agent can also be used. After the contrast agent is injected through the nasogastric tube, it can be observed dynamically under fluoroscopy to obtain more. Useful information, the most typical manifestation of midgut torsion is "bird's beak-like" changes in the second and third segments of the duodenum; partial obstruction of the duodenum may be "spiral-like" changes, it is necessary to point out that when acute intestinal torsion is suspected This check is not appropriate.

If there is no volvulus in the child with poor intestinal rotation, upper gastrointestinal angiography plays an important role in determining the position of the duodenal jejunum junction (the ligament of the ligament). Under normal circumstances, the ligament should be located at the level of the left antrum of the spine. Close to the posterior abdominal wall, if there is poor rotation of the intestine, the duodenum does not rotate normally around the SMA, it is located below the duodenal bulb of the right side of the spine, and is closer to the ventral side than the normal part. The fluid-filled dilated bowel segment can also be shown to move the duodenal jejunum joint down, causing a false rotation artifact, at which point a contrast agent can be injected through the anus to determine the location of the ileocecal area.

3. Barium enema

Although barium enema is one of the methods for diagnosing intestinal malrotation, it is more limited than the upper gastrointestinal angiography, mainly because 15% of normal infants have free or high ileocecal position; while infants have a relatively long colon It brings difficulties to the identification and filming of the ileocecal area; more importantly, the position of the ileocecal part of the patient with poor intestinal rotation may be normal.

Despite the above limitations, if the barium enema examination finds that the entire colon is located in the left abdomen (see no rotation at all), or (and) the ascending colon is abnormally shortened and the ileocecal area is above the iliac wing, it is also possible to diagnose intestinal malrotation.

4. Ultrasound

As a non-invasive test, ultrasound can help diagnose intestinal malrotation by exploring the location and orientation of the vessels on the mesenteric membrane. Normally, the superior mesenteric vein (SMV) is located on the right side of the SMA. There may be poor intestinal rotation, however, ultrasound does not accurately diagnose intestinal malrotation. Some authors reported that 9 patients with surgically confirmed intestinal dysplasia, only 6 cases of B-ultrasound found mesenteric vascular abnormalities; another group of 249 cases were excluded Among the patients with pyloric stenosis and ultrasonography, only 9 patients found mesenteric vascular abnormalities, of which 5 patients with SMV on the left side of the SMA had intestinal malrotation, and the remaining 4 SMVs were located on the ventral side of SMA, but only 1 case had intestinal Poor rotation, the position of the mesenteric vessels in patients with poor intestinal rotation may be completely normal, and the abnormal position of the blood vessels can not determine the poor rotation of the intestine. Therefore, ultrasound is not the first choice for the diagnosis of intestinal malrotation, and its effect is limited to the exclusion of pyloric stenosis in children with vomiting.

Diagnosis and diagnosis of pediatric intestinal malrotation

Anyone suspected of poor rotation or midgut torsion, imaging examination before surgery, including abdominal plain film, upper and lower gastrointestinal angiography, or CT, B-ultrasound, etc., can be clearly diagnosed.

It should be differentiated from congenital intestinal stenosis, intestinal atresia, and ring-shaped pancreas. It can be identified by the above imaging examination. If it is an acute midgut torsion, it should be differentiated from intestinal obstruction, sepsis, hemorrhagic intracranial hypertension. Examination and imaging studies can confirm the diagnosis.

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