Pediatric motility ileus

　　One, Etiology

　　1. Secondary complications of other diseases. In children, especially in young infants, various severe diseases can cause intestinal paralysis, such as enteritis, sepsis, pneumonia, etc. The mechanism of the occurrence of intestinal paralysis is due to excessive excitation of the sympathetic nervous system, which has an inhibitory effect on the intestines. Therefore, after being inhibited, intestinal peristalsis disappears, and the normal peristalsis of the intestines causes gases and fluids to be absorbed or moved downward at any time. This is why the small intestine usually does not contain gas. After the occurrence of intestinal paralysis, peristalsis stops, absorption function is impaired, and gases and fluids accumulate, causing the intestinal loops to swell further, leading to the loss of motility and forming a vicious cycle.

　　2. Primary (idiopathic) intestinal motility abnormalities without obvious etiology, some children show symptoms from birth, and some may not show symptoms until adolescence or young adulthood. The symptoms of intestinal obstruction can be persistent or recurrent, making diagnosis and treatment difficult and with a high mortality rate. If the abnormality is in a segment of the intestinal tract, the segment can be resected or bypassed, and the child can gradually recover.

　　Two, Pathogenesis

　　Generally, the downward movement of intestinal contents is mainly promoted by the movement and contraction of the intestinal wall muscles. The movement of the intestinal wall muscles relies on the function of the intestinal wall muscles themselves, and on the regulatory function of the autonomic nervous system that controls this area. In recent years, it has been reported that gastrointestinal hormones have a significant impact on intestinal wall movement. Therefore, the causes of dynamic intestinal obstruction should be considered from the aspects of the intestinal wall itself, the autonomic nervous system, or gastrointestinal hormones. Pathological changes are divided into three types: intestinal muscle lesions, intermuscular plexus lesions, and non-neuromuscular lesions. After intestinal paralysis occurs, both the small and large intestines become distended and inflated, the intestinal wall becomes thin, and the movement and absorption abilities are lost. Moreover, due to the expansion of the intestinal loops, the blood supply of the intestinal wall is compressed, leading to venous congestion or arterial ischemia, and fluid leakage in the abdominal cavity. With the increase of intestinal content and bacterial metabolites, children may develop toxic reactions. Clinically, symptoms of complete or partial intestinal obstruction may appear. In secondary dynamic intestinal obstruction, there are usually no abnormalities in the intestinal wall muscles and nerve tissues. In primary dynamic intestinal obstruction, symptoms appear from birth, and there are often nerve plexuses, ganglion cells, or abnormal development of neurons in the intermuscular or submucosal areas of the intestinal wall. The number of neurons is reduced, and the morphology becomes smaller. Under electron microscopy, the intestinal wall smooth muscle fibers can be found to have vacuolar degeneration. Dynamic intestinal obstruction with no obvious etiology after birth often shows abnormal conduction of nerve excitation and inhibition.

　　1. Intestinal distension:After the occurrence of intestinal obstruction, the intestinal cavity accumulates a large amount of gas that cannot be discharged, leading to intestinal distension. The main source of the gas (about 70%) is the air entering the digestive tract of the patient. Intestinal distension increases the intracavity pressure, thins the intestinal wall, and seriously impairs the blood circulation of the intestinal wall. In addition, when the intestinal cavity is distended, the abdominal pressure increases, the diaphragm rises, and abdominal breathing is weakened, which can affect the respiratory and circulatory function of the child.

　　2. Loss of body fluids, electrolytes, and acid-base balance disorders:During intestinal obstruction, due to frequent vomiting, there is severe loss of body fluids and electrolytes.

　　4. Infection:During intestinal obstruction, intestinal bacteria rapidly overproliferate, leading to dysbiosis. Due to the severe damage to the intestinal mucosal barrier, bacteria in the intestines can also migrate to extraintestinal organs, causing enterogenous infection.

　　1. Secondary dynamic intestinal obstruction

　　The clinical manifestations are often severe, mainly characterized by abdominal pain, abdominal distension, vomiting, and non-defecation. The symptoms at onset vary according to the etiology causing intestinal paralysis. After the paralysis is formed, there is abdominal distension, few or absent bowel sounds, and infants may experience respiratory distress due to abdominal distension. Early on, there is often no vomiting, but vomiting occurs with increased abdominal distension, containing fecal-like matter, with reduced defecation frequency, eventually leading to the inability to pass gas or defecate.

　　2. Primary dynamic intestinal obstruction

　　The clinical manifestations are mainly subacute, chronic, recurrent, or persistent with periodic exacerbation of intestinal obstruction syndrome, with vomiting, abdominal distension, and constipation as the main symptoms. The severity varies from time to time, with reduced vomiting symptoms and slight排气 and defecation during mild periods, but it is difficult to disappear from abdominal distension. Due to long-term malabsorption of nutrition, children are generally thin and stunted, with a bulging abdominal shape, weak or absent bowel sounds.

　　The primary etiology of pediatric dynamic intestinal obstruction is still under study, and there is a significant familial genetic predisposition. Genetic counseling work should be done well. Secondary to enteritis, sepsis, pneumonia, hypokalemia, drug poisoning, and other diseases should be treated actively to prevent the occurrence of intestinal paralysis and to worsen the condition. This condition also disappears with the improvement of the primary disease. If related complications occur, pay attention to active treatment and correction to avoid further aggravation of the condition.

　　1. X-ray diagnosis

　　It is an important diagnostic method, showing different degrees and locations of intestinal obstruction X-ray signs on the透视 or abdominal flat film. Barium meal radiography of the gastrointestinal tract is an important means to exclude mechanical intestinal obstruction. In cases of dynamic intestinal obstruction, there may be phenomena of proximal intestinal dilatation and retention of barium, and standing and supine flat films can show uniform dilatation and air filling of the small and large intestines, with a liquid level. If it cannot be determined whether the aerated intestinal loop is the colon, a small amount of barium enema can be used under low pressure. If it is confirmed that the colon is aerated and dilated, the diagnosis of intestinal paralysis can be established.

　　2. Special Examination

　　Gastrointestinal pressure measurement and gastrointestinal electrography are effective methods for diagnosing dynamic intestinal obstruction. Rectal pressure measurement and biopsy are used to exclude congenital megacolon.

　　Fasting and gastrointestinal decompression to reduce abdominal distension. The position is semi-recumbent to reduce pressure on the diaphragm. Closely observe changes in the condition, and if the condition worsens, be alert to the occurrence of strangulated intestinal obstruction and timely surgical treatment. For adhesive intestinal obstruction during the remission period, attention should be paid to diet, do not eat hard food, and eat soft and loose food. After a meal, avoid strenuous exercise to prevent intussusception.

　　1. Treatment

　　If it is secondary, treatment should be given for the primary disease. Generally, non-surgical therapies such as fasting, gastrointestinal decompression, acupuncture at Zusanli, Hegu, moxibustion at Zhongwan, Guanyuan points, and renal cyst closure can prevent severe abdominal distension. When there is no mechanical intestinal obstruction, neostigmine (0.045-0.060mg/kg) can be used in large doses to promote peristalsis. Anal gas release, small amounts of 2% soap water or small amounts of 3% saline enema, and other stimulants of colonic activity can also help reduce abdominal distension. Parenteral nutrition is very important for children with various types of dynamic intestinal obstruction. If there is a suspicion of surgical conditions in the abdominal cavity, or if abdominal distension does not improve after non-surgical therapy, and the colon is completely deflated, then abdominal exploration should be considered. According to the child's condition and what is seen during surgery, abdominal drainage, mesenteric closure, intestinal decompression, or enterostomy surgery may be performed. The purpose of nutritional support is to enable the child to develop normally, reduce complications, and alleviate symptoms as much as possible. The gastrointestinal motility of children with pseudo-obstruction can improve with the improvement of nutritional status and worsen with the development of malnutrition. Some children may need partial or total parenteral nutrition.

　　2. Prognosis

　　General intestinal paralysis after normal abdominal surgery can usually recover in a short time after proper treatment such as fasting and decompression. Toxic intestinal paralysis is often part of the terminal stage of the primary disease, so the prognosis is poor. For primary pseudo-obstruction, if symptoms appear from birth, due to the difficulty in maintaining nutrition, most cannot grow up to adulthood.