Vomiting in children

　　I. Vomiting

　　It refers to the phenomenon that non-forced digestive secretion or gastric contents flow out of the stomach or esophagus. It is usually not accompanied by heart or forced abdominal muscle contraction. Vomiting can be physiological, or it can be caused by pathological reasons.

　　1. Physiological

　　In the first few weeks of life, after feeding, milk (with or without milk curds) can be seen in the mouth about 0.5 to 1 hour, which is usually referred to as 'spitting up'. The appetite, sleep, spirit, and weight gain of the infant are all normal. There is often no obvious cause, and it usually stops naturally within 7 to 8 months without treatment.

　　2. Pathological

　　(1) Feeding problems refer to 'vomiting' caused by improper feeding techniques. For example, incorrect posture during breastfeeding (such as poor connection between the nipple and the baby's mouth, the nose close to the breast, incorrect lying position), rapid milk ejection, excessive milk flow leading to rapid baby suckling and swallowing, excessive milk intake, inverted nipple, difficulty in breastfeeding, low milk temperature during artificial feeding, too small diameter of the nipple hole, or insufficient calories in the milk, and insufficient feeding. Infants often have non-nutritive suckling, resulting in a large amount of gas in the stomach. After feeding, the gas in the stomach is not exhaled in an upright position, or various nursing care is given to the baby after feeding, such as changing diapers, bathing, giving medicine, etc. Feeding during crying or before crying, and forcing infants, especially premature infants, to eat, can also cause it.

　　(2) Congenital esophageal obstruction is often diagnosed by X-ray examination.

　　① Complete and incomplete obstruction is caused by structural abnormalities of the esophagus itself, including intraluminal and wall lesions.

　　② Congenital esophageal atresia: Esophageal atresia is a congenital malformation of unknown etiology. It is not uncommon in clinical practice, with about 1 case in every 4000 live births. Esophageal atresia can be associated with or without esophageal tracheal fistula, but it often easily complicates with spinal, anal, heart, kidney, and limb malformations. It is generally divided into five types: Type I (both proximal and distal ends of the esophagus are blind without esophageal tracheal fistula), Type II (the proximal end has a fistula connected to the trachea, the distal end is blind, and the lower stomach communicates), Type III (the proximal end is blind, and the distal end has a fistula connected to the trachea), Type IV (esophageal atresia, but both upper and lower segments are connected by fistulas and trachea), and Type V (the esophagus is patent, but there is a fistula connecting to the trachea from below to above) or Type N. Among them, Type III is the most common, accounting for more than 90%, followed by Type I, which accounts for only 5% to 7%.

　　Children with congenital esophageal atresia have significant difficulty swallowing. In the early stages of life, they may spit out foam and milk, and the milk may reflux from the mouth or nose. Since the milk has not been in contact with gastric acid, the vomit does not contain milk curds and does not contain bile. Newborns often experience difficulty breathing and cyanosis due to aspiration, which improves significantly after suctioning. Such repeated episodes may lead to secondary pneumonia and threaten life. Diagnosis mainly relies on taking an upright chest and abdominal X-ray film after inserting a 10-number rubber or silicone tube into the food.

　　③ Congenital esophageal stenosis: rare. The etiology is unknown, and there are various theories. It can be divided into three types according to histology: thickening of a segment of the esophageal wall, a membrane web or septum, and remnants of tracheobronchial cartilage within the wall. The septal type may have clinical manifestations similar to esophageal atresia. Esophagoscopy can be used for both diagnosis and treatment. Children with esophageal stenosis often experience vomiting during feeding, difficulty swallowing, aspiration, recurrent respiratory tract infections, weight loss, and malnutrition when they start to add complementary foods a few months after birth. X-ray esophagram and endoscopic examination can be used for diagnosis. However, the presence of cartilage remnants in the 1/3rd segment or lower end of the esophagus is often detected during surgery or pathological diagnosis. This condition may be associated with congenital esophageal atresia.

　　④ Congenital esophageal duplication anomaly: It ranks second in incidence among congenital intestinal duplication anomalies. It is not uncommon in clinical practice. It can manifest as cystic, tubular, or diverticular. It is more common at the lower end of the esophagus in the right posterior mediastinum. Some are connected with the spinal cavity and accompanied by vertebral malformation or intramedullary mass. According to statistics, 8 cases (12.3%) out of 65 cases have concurrent intraperitoneal duplication anomalies. Sometimes there are no symptoms at all, and a mass is only found during occasional chest X-ray examination. Some present mainly with respiratory symptoms such as cough, wheezing, pneumonia, hemoptysis, and chest pain. About 15% of children show dysphagia, vomiting, epigastric pain, and hematochezia. X-ray film of the anteroposterior and lateral chest and abdominal flat plates, esophageal contrast, B-ultrasound or color Doppler ultrasound, CT, radionuclide, and magnetic resonance imaging can be used for preoperative diagnosis. Myelography is needed when there is a suspicion of intraspinal mass. Pay attention to differentiate from lymphoma, neurogenic tumors, and hemangiomas, etc.

　　⑤ Achalasia (esophageal spasm, idiopathic esophageal dilation): The etiology is unknown. According to statistics, 5.3% of 167 pediatric cases are neonates. Due to the dysfunction of cholinergic nerves in the esophageal wall, the muscles at the lower end of the esophagus contract, the lower esophageal sphincter pressure rises, food is retained in the esophagus, gradually expands, and inflammatory changes and ulcer formation occur in the mucosa. The degree of dysphagia varies, worsening progressively, and is sometimes affected by psychological factors. Content is milk without milk clots or undigested food refluxing from the esophagus to the mouth or vomiting, sometimes containing coffee-colored mucus. In the long run, malnutrition, anemia, and malnutrition may occur. Children may complain of heartburn or chest pain caused by peptic esophagitis. Barium meal X-ray examination can be used for diagnosis. Esophagogastroduodenoscopy and manometry are used more and more.

　　⑤ Gastroesophageal reflux (GER) refers to the phenomenon of stomach and part of the duodenum contents refluxing into the esophagus. In children, except for some that are physiological and disappear around 8 to 10 months after birth, other pathological cases can cause serious complications. This disease has been one of the hot topics in pediatric surgery research in China in recent years. The causes are complex and diverse, mainly due to the abnormally sustained decrease in lower esophageal sphincter pressure (LESP) at the lower end of the esophagus. Other factors such as a large His angle, diaphragmatic elasticity, abdominal pressure, esophageal mucosal pleats, and gastric volume can reduce the anti-reflux barrier function of the esophagus, decrease the esophageal clearance ability, cause abnormal function of the stomach and duodenum, leading to gastroesophageal reflux, and then causing inflammatory changes in the esophageal mucosa, ulcers, bleeding, and stricture, etc.

　　Some believe that 50% of GER occurs in neonates and infants, with 60% to 80% having projectile vomiting within the first week of life, and 40% having pyloric stenosis. The vomit may contain bile and coffee-colored or blood-containing fluid. Older children may have retrosternal burning sensation, pain on swallowing, swallowing difficulties, wheezing, asthma, asphyxia, and symptoms of chronic respiratory tract infection. Statistics indicate that 25% to 80% of asthmatic children and approximately 46% to 63% of chronic respiratory diseases are associated with GER! Some diseases related to neurologic and psychiatric factors, such as cerebral palsy, mental retardation, rumination, and Sandifer syndrome with different motor postures of the neck and upper trunk, and certain esophageal atresia surgeries can also be associated with GER. Over time, conditions such as melena, anemia, chronic malnutrition, and even delayed growth and development in children can occur.

　　The methods commonly used for diagnosing GER include X-ray esophagogram and barium esophagogram. It can confirm the diagnosis and differentiate between mild and severe cases. The measurement of LESP, less than 1.96 kPa (20 cmH2O), has diagnostic significance. In recent years, Wang Weilin and others have used esophageal and gastric dual pH microelectrodes to monitor children in both supine and lying positions during fasting (excluding meals and the 2 hours after meals) and for 24 hours. The results show that acidic gastroesophageal reflux is defined as esophageal pH less than 4, which is considered alkaline reflux standard, with gastric pH greater than 7 as alkaline gastroesophageal reflux. If the gastric pH is greater than 4 and the esophageal pH is less than 7, it is considered alkaline gastroesophageal reflux. The conclusion is that gastroesophageal reflux occurring on the basis of duodenogastric reflux is one of the main types of pediatric gastric tube reflux. Dual pH monitoring of the esophageal and gastric segments during fasting and lying down has greater diagnostic significance in pathological reflux. In addition, endoscopy, isotope scanning, and ultrasound examinations can also help with comprehensive judgment and differential diagnosis.

　　⑥ Esophageal hiatus hernia: This is a relatively common congenital malformation. The esophageal hiatus is abnormally wide due to poor development of the diaphragm. When lying flat or abdominal pressure increases, the fundus of the stomach, the cardia, and part of the upper esophagus slide into the mediastinum, causing reflux of gastric contents into the esophagus, leading to mucosal inflammation, and even ulcers and bleeding, which may ultimately result in scar strictures. The child may vomit food, which may contain coffee-colored or red blood. Symptoms worsen when lying flat or at night. Ultimately, esophageal stricture, swallowing difficulties, anemia, and malnutrition may occur. Respiratory symptoms such as cough, asthma, and inflammation can be caused by aspiration, and in severe cases, can lead to apnea or sudden death. Diagnosis mainly relies on barium esophagogram and barium enema, with iohexol and diatrizoate used in small infants to prevent aspiration of barium. Changing to a semi-sitting position and increasing the viscosity of food can significantly reduce vomiting in small infants.

　　⑦ Congenital short esophagus: very rare. The cardia and part of the fundus of the stomach are located in the mediastinum. Swallowing difficulties and regurgitation of gastric juice can occur due to compression, leading to esophageal inflammation and ulceration, and can cause vomiting of blood. Barium esophagogram is required for diagnosis. Be aware of the distinction from esophageal hiatus hernia.

　　(3) Extraluminal compression of the esophagus due to congenital diseases outside the esophagus, causing obstruction of the esophagus. Swallowing difficulties occur after eating, especially when eating solid food, and may lead to vomiting, aspiration, or asphyxia. It can be seen in cases of congenital vascular ring surrounding the esophagus, which is a rare clinical condition.

　　3. Acquired esophageal diseases

　　(1) Esophageal inflammation and stricture Due to various congenital and acquired diseases, such as gastroesophageal reflux, achalasia, pneumonia, scarlet fever, diphtheria, Helicobacter pylori infection, asthma, etc., children may have repeated vomiting, gastric acid stimulation of food mucosa causing inflammation, ulceration, and stricture. Emergency cases of regurgitation or vomiting also include common cases of young children accidentally ingesting domestic alkali water, alkaline liquid in battery cells, or corrosive liquids such as strong acids and alkalis used in industry, causing acute damage to the food mucosa and/or muscle layer, leading to inflammation, perforation, or stricture.

　　(2) Esophageal foreign bodies such as coins, safety pins, fish bones, seeds, peanuts, beans, jujube seeds, plastic toys, etc. Mild cases can cause excessive saliva, difficulty in swallowing, and vomiting; severe cases can cause burning sensation and pain behind the sternum, even perforation, abscess formation, and esophageal fistula after ulceration. In young children, difficulty in breathing can also occur due to the foreign body pressing on the trachea.

　　(3) Post-esophageal abscess The causes of post-esophageal abscess include downward extension of retropharyngeal abscess, esophageal perforation caused by various reasons, secondary abscess, mediastinal lymph node abscess, tracheotomy tube compressive ulcer, and spinal tuberculosis abscess. Regurgitation and vomiting occur due to compression obstruction, difficulty in swallowing, or pain. There are also reports of local tracheobronchial lymph node inflammation resulting in adhesions, leading to local esophageal dilation, formation of pseudodiverticula, food retention. Mucosal inflammatory changes can cause regurgitation.

　　(4) Esophageal trauma Esophageal trauma, other than foreign body causes, is often iatrogenic, such as accidental injury during endoscopic examination and injection treatment for esophageal varices, or during insertion of gastrointestinal decompression tubes or artificial ventilation. At this time, the vomit often contains blood. Diagnosis is not difficult based on medical history, X-ray contrast, and photographs. When there is frothy fluid in the chest drain tube after esophageal end-to-end anastomosis for esophageal atresia, it often indicates anastomotic fistula, and the baby's mouth may also have frothy mucus regurgitation.

　　(5) Ruminating is rarely reported in Chinese literature. It is more common in infants aged 3-4 months who regurgitate food after re-chewing it. They raise their heads, stick out their tongues and lower jaws, and chew and swallow rhythmically until regurgitation occurs. At this time, some food may overflow from the mouth, while some is swallowed. Infants are in good spirits and appear alert. Parents often complain of vomiting or failure to gain weight. Sometimes it occurs when the mother is frightened, depressed, or unable to intervene about the baby's illness. Infants with low intelligence or mental deficiency may show persistent rumination. At this time, the baby can recover when the nurse or others increase their care and love for the baby.

　　(6) Other causes When the intraperitoneal pressure increases due to tumors, ascites, organ enlargement, and intestinal distension caused by difficulty in breathing, diaphragmatic elevation, lower esophageal segment or stomach torsion, and neonatal anesthesia withdrawal may all lead to regurgitation or vomiting.

　　2. Vomiting

　　It refers to the forced expulsion of the contents of the stomach or part of the small intestine through the mouth. It is often accompanied by nausea and strong contraction of the abdominal muscles.

　　The causes of vomiting can be divided into three major categories: obstructive, reflex, and central. The former is often due to surgical causes, while the latter two are more commonly caused by internal medicine diseases.

　　1. Obstructive Vomiting

　　The obstruction of the digestive tract can be caused by congenital malformations of the digestive tract or certain acquired diseases.

　　（1）先天性消化道畸形包括管腔内闭锁、狭窄或管壁发育不良或管外压迫。在新生儿，这是外科性呕吐的最主要病种。消化道自上而下有食物闭锁、胃扭转、幽门痉挛、幽门肥厚性狭窄、幽门瓣膜、十二指肠闭锁或狭窄、环状胰腺、肠旋转不良、空回肠闭锁或狭窄、肠无神经节症（巨结肠）、巨结肠炎缘病、直肠肛门畸形（包括肛门闭锁或狭窄及有时合并的直肠泌尿系瘘、直肠阴道瘘、直肠前庭瘘、一穴肛等）及消化道重复畸形等。此外，小左结肠综合征、巨膀胱细小结肠肠蠕动不良综合征少见。还有胃壁肌肉发育不良合并胃穿孔、胎粪阻塞综合征、胎粪性腹膜炎临床上不太少见。胎粪性肠梗阻在中国各民族均罕见。

　　肠壁外压迫可由先天性十二指肠、空回肠前异常纤维膜或索带、胎粪性腹膜炎后遗粘连、十二指肠前门静脉、肠系膜裂孔疝、嵌顿腹股沟斜疝或横膈疝等病引起。食管裂孔疝也属于畸形病因造成的不全性消化道梗阻而呕吐。

　　（2）后天性消化道疾病所致如肠管或腹腔炎症后遗粘连、婴儿常见的急性肠套叠（回盲、回结或回回型等）、胃肠道异物（毛发团、胃结石等）及少见的乙状结肠扭转早产婴可见乳凝块肠梗阻。幼儿可因便秘而引起腹痛和呕吐，伴有尿潴留。蛔虫性肠梗阻和肠扭转则只是由于大中城市内化肥的普遍应用才变得少见。

　　由于肠梗阻的病因不同、病程不一（急性或慢性）、性质各异（完全性、不完全性或突发性）及病变位置有别（高位、中位或低位），所以呕吐发生的时间、性质、内容、颜色及量等临床表现有明显差异，其中病因与年龄的关系紧密。

　　2、反射性呕吐

　　多由胃肠道受生物、物理或化学性刺激引起，有时为多种因素混合造成。

　　三、发病机制

　　呕吐是一种神经反射，过程极为复杂。由外周各器官和组织接受的外来或内源性的生物、物理和化学的刺激，经过体神经和内脏神经或血循环传入中枢神经系统。在延髓的呕吐枢（接受来自胃肠道及其他内脏神经冲动）和在第四脑室底部的后极区，即化学感受器触发区（chemoreceptortriggerzone，CTZ）（接受来自血循环的化学和药物的刺激），反射信号经过迷走神经和脊神经下传至各相应器官引起呕吐反应。近年研究证明，多巴胺受体在CTZ对呕吐的介导中有重要作用。CTZ还含有5-羟色胺、去甲肾上腺素、P物质、脑啡肽和γ氨基丁酸等。某些此类内源性神经递质和神经肽均能经血液循环或直接对CTZ作用而引起呕吐。

　　Severe vomiting in children can lead to apnea, cyanosis in infants; if not carefully avoided, aspiration pneumonia can occur; repeated vomiting can lead to complex water and electrolyte imbalances, and in severe cases, even death. Acute pneumonia can have vomiting at the early stage of onset, which is more common in children. During the convulsive stage of whooping cough, reflex vomiting often occurs after the attack of convulsive cough, expelling the contents of the stomach. Vomiting, abdominal pain, and the cessation of defecation and排气 are often severe and accompanied by nausea. Early vomiting is usually reflexive, initially food and gastric juice, followed by yellow-green bile. After the reflexive vomiting stops, typical obstructive and regurgitative vomiting may appear after a period of time. The interval between the two types of vomiting depends on the height of the obstruction site. The higher the obstruction site, the shorter the interval. In the case of low ileal obstruction, the interval is longer. Regurgitative vomiting is caused by the inability of the fluid in the intestine to pass through the obstruction site, accumulating in the upper intestinal segment to a considerable amount, forming an intestinal peristalsis and vomiting. The early vomit is bile-like, the liquid turns brown or light green, and in the late stage, it is a liquid with fecal odor. This is due to the prolonged retention of food in the lower intestines, which is decomposed and fermented by the intestinal bacteria.

　　Collecting Medical History

　　Due to the fact that the spectrum of disabilities varies with different ages, the focus of collecting medical history should be different. Generally speaking, the vomiting in children of various ages is mainly due to internal medicine reasons. For example, during the neonatal period, in the 266 cases of vomiting statistically recorded by Xinhua Hospital in Shanghai, 233 cases (87.9%) were caused by internal medicine reasons, and the remaining 33 cases (12.1%) were caused by surgical diseases. Among the diseases caused by internal medicine, infectious causes are the most common, while those caused by surgical diseases are mainly abdominal organ infection and gastrointestinal obstruction. Since vomiting is a symptom of the digestive system, the collection of medical history should first focus on feeding methods, food content, time, and habits. For newborns, in addition to paying attention to the occurrence and development of vomiting, the medical history of the mother's pregnancy, delivery, and medication should also be understood. In recent years, there have been many changes in the dietary habits of children in urban areas, among which there are many commonalities, as well as unreasonable and unscientific aspects. It is necessary to understand them carefully. Changes in body weight can often objectively reflect the severity of vomiting and its impact on children, which needs to be emphasized. It is also necessary to listen carefully to the descriptions of parents and older children.

　　Analysis of several symptoms

　　Always consider age factors and the disease spectrum to distinguish between functional and organic, and between medical and surgical vomiting as soon as possible, in order to determine the principles of diagnosis and treatment.

　　1. Vomiting

　　Pay attention to its occurrence, manifestation, and changes.

　　(1) Time and frequency The time when vomiting starts and the number of times a day the patient vomits can vary significantly due to diseases, such as a newborn starting to vomit coffee-colored mucus within a few hours after birth and a 3-year-old child repeatedly vomiting coffee-colored matter for over 2 years, which clearly originates from different causes. The former may be due to the accidental swallowing of maternal blood, while the latter is more likely to be due to esophageal hiatus hernia.

　　(2) The manner can be like overflow, such as milk flowing out of the corner of a newborn's mouth in small amounts; or it can reflux from the mouth; or it can be vomited out in large amounts from the mouth; or it can be sprayed out simultaneously from the mouth and nose. During the neonatal period, the former may be physiological, while the latter is more common in congenital hypertrophic pyloric stenosis.

　　(3) The content and nature of vomiting have important reference value for the diagnosis of gastrointestinal obstruction.

　　① Clear or frothy mucus, undigested milk or food indicates that the saliva is blocked and the obstruction is above the esophagus, and it is seen in congenital esophageal atresia, esophageal stenosis and achalasia caused by food inflammation in all age groups.

　　② Mucus, milk clots, and gastric contents indicate an obstruction in the pylorus and are seen in neonatal hypertrophic pyloric stenosis, pyloric valve, and pyloric scar stenosis in older children, and occasionally in infants who have accidentally swallowed corrosive liquids. When it contains a small amount of blood or coffee, it can be seen in esophageal hiatus hernia and gastroesophageal reflux in children of all ages, and excessive eating can cause vomiting of sour, undigested food.

　　③ Clear yellow or green mucus, sometimes mixed with a small amount of milk clots or food, usually indicates an obstruction in the duodenum and is seen in severe functional vomiting in all age groups; in newborns, it is more common in duodenal atresia or stenosis, annular pancreas, and malrotation of the intestines.

　　(4) A yellow-green liquid mixed with a small amount of food residue indicates that the proximal jejunum and the nearby intestinal tract are not unobstructed, and it is seen in high jejunal atresia or adhesive ileus, and during intestinal paralysis.

　　(5) A light brown-green fecal-like substance indicates that the obstruction is in the middle and lower segments of the jejunum or its distal part. During the neonatal period, it is often considered to be atresia of the jejunum and ileum or Hirschsprung's disease or rectal and anal malformations. In other age groups, it indicates that there is a low gastrointestinal obstruction due to various causes.

　　(6) The amount of blood, speed, and location of bleeding determine the blood content and color in the vomit. A small amount of blood mixed with gastric acid appears brown and can be seen in newborns who have swallowed amniotic fluid containing maternal blood or after suckling a cracked nipple, neonatal spontaneous hemorrhage, early gastric perforation, late pyloric stenosis; in patients of all ages with esophageal hiatus hernia, severe and recurrent vomiting due to various causes, and in critically ill patients with disseminated intravascular coagulation, the blood volume is less, the color is brown or dark red, there is thrombocytopenic purpura, hemophilia, aplastic anemia, especially at certain stages of leukemia when gastrointestinal bleeding may occur, portal hypertension with esophageal variceal rupture, gastric mucosal ulcer bleeding after burns or asphyxia, acute hemorrhagic gastritis caused by oral intake of salicylic acid or theophylline, and other medications can all lead to hematemesis. Large bleeding in the jejunum can also result in vomiting of fresh blood. Coughing up blood in children is rare and difficult to differentiate from vomiting, and it requires reliance on other symptoms and signs.

　　It is noteworthy that the content and nature of vomiting can change with the course of the disease. For example, in the early stage of neonatal low intestinal atresia, vomiting of colorless mucus may occur, and it may turn into bile-like after 1-2 days. After the improvement of systemic infection and severe sepsis, and the reduction of intestinal paralysis, the contents of vomiting or gastrointestinal decompression may change from turbid, yellow-green fecal-like juice to clear mucus. Therefore, it is necessary to combine other accompanying symptoms and signs, and observe dynamically to accurately judge the clinical significance of vomiting.

　　2. Abdominal Distension

　　It often occurs with vomiting symptoms and needs to be distinguished from abdominal distension caused by abdominal mass, large amounts of fluid or gas in the peritoneal or intestinal cavity. Abdominal distension can be localized or generalized. Whether abdominal distension is accompanied by intestinal, gastric, or peristaltic waves, and the degree of abdominal distension is mild, moderate, or severe.

　　3. Abdominal Pain

　　It is also a common symptom accompanied by vomiting, which requires careful understanding of the relationship between the onset time of abdominal pain, the nature of abdominal pain (spasmodic, persistent, or progressively severe), and the location of abdominal pain. When vomiting is accompanied by abdominal pain, one should be vigilant about the possibility of surgical acute abdomen, especially in newborns, particularly premature infants, who often lack expressions of abdominal pain in complete intestinal obstruction of digestive tract anomalies, and may only show malaise without muscle tension in peritonitis with perforation.

　　4. Abnormal Stool

　　Abnormalities can manifest as traits, quantity, time, frequency, and excretion site, with short-term vomiting several times, accompanied by a decrease in the frequency and quantity of stool, dryness, and the child showing no other obvious discomfort, indicating a high possibility of digestive dysfunction; if accompanied by loose stools and fever, it indicates gastroenteritis. Vomiting with abdominal pain and cessation of defecation should first be considered as a surgical acute abdomen, which is particularly significant in newborns. Usually, more than 90% of full-term newborns should start defecating within 24 hours after birth, and about 98% should do so within 48 hours. The meconium should be completely excreted within 2-3 days, with a total volume of about 60-90%. In congenital hypertrophic pyloric stenosis, due to large amounts of vomiting, constipation may occur, and even the patient may present with constipation as the main complaint. In newborns with ileocolonic atresia, the distal colon is small, without meconium, and sometimes only a small amount of gray-green mucus is excreted. Newborns with aganglionic megacolon often have no history of spontaneous meconium excretion at birth, but a large amount of gas accompanied by meconium is excreted in a burst-like manner during rectal examination, using an enema or lavage. Accompanied by marked yellow-green bilious vomiting, aganglionic megacolon in other age groups often only presents with constipation and abdominal distension without vomiting. In congenital anal stenosis, the amount of meconium is significantly reduced, and in rectal anal atresia, there is no meconium excretion (without fistula) or the excretion outlet of meconium is abnormally located (in the perineum, vestibule, vagina, scrotum, urethra, or bladder). In addition, when intestinal volvulus, intestinal strangulation, intussusception, intestinal duplication畸形, Meckel's diverticulum, and other causes lead to gastrointestinal bleeding, blood in stool of varying degrees may occur (such as black tarry, dark red, bright red, and different volumes), or only positive occult blood test. When stool is green, with mucus and curdles, watery, purulent, or mucous and bloody, it often belongs to medical causes.

　　5. Other symptoms

　　In pediatric clinical practice, vomiting is an extremely common symptom, but it is often not the only symptom. In addition to the aforementioned abdominal distension, abdominal pain, and fecal abnormalities associated with vomiting, other symptoms of the digestive system may also occur, such as loss of appetite, increased appetite, hiccups, belching, acid regurgitation, heartburn, etc. Some or certain symptoms of the respiratory, cardiovascular, urinary, endocrine, or nervous systems may coexist with vomiting, and fever is common. All these symptoms should be taken seriously and carefully considered so that during physical examination, laboratory, and imaging, the focus can be selected.

　　1. Breastfeeding newborns and infants should not be too hurried. After breastfeeding, hold the child's body straight and gently pat the back until hiccups occur.

　　2. Pay attention to diet, eat at regular intervals and in appropriate amounts, avoid overeating, and do not overindulge in fried, greasy foods and cold drinks.

　　3. For children with mild vomiting, easily digestible liquid or semi-liquid foods can be consumed, given in small amounts multiple times. For children with severe vomiting, temporary fasting is recommended.

　　4. Let the child lie on their side to prevent vomiting material from being inhaled.

　　5. When administering medication, the liquid should not be too hot, and the medication should be taken slowly. You can take small amounts multiple times, and if necessary, you can take a sip, pause for a moment, and then take another sip.

　　6. Actively investigate the cause of vomiting and treat according to the cause.

　　1. If routine examination shows normal vomiting, vomiting caused by infection may have infectious blood pictures, with increased peripheral blood leukocytes and neutrophils; if complications include water and electrolyte imbalance, there are usually corresponding laboratory test results, and serum sodium, potassium, chloride, calcium, blood pH value, blood urea nitrogen, blood glucose, and urine ketone bodies should be checked.

　　2. Routine X-ray, ultrasound, and other examinations should be carried out actively to search for the cause.

　　3. Abdominal X-ray透视 or flat film, gastrointestinal barium meal透视 or filming, endoscopy, and other examinations are helpful in understanding gastrointestinal obstruction, abdominal inflammation, or congenital gastrointestinal malformations. When suspected of intracranial hemorrhage or intracranial space-occupying lesions, brain ultrasound, cerebral angiography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) can be performed.

　　How should patients eat:

　　Short-term fasting followed by light diet is often the case where parents, seeing their child vomiting, become flustered and think their child is可怜, so they eagerly feed him food after vomiting, only to trigger a second wave of vomiting (which may even be more than what was eaten!). In fact, the best way to deal with vomiting is to temporarily fast for four to six hours, including not drinking water or milk, waiting for the vomiting reaction to subside. During this period, if the baby is crying for water, you can moisten the mouth with a cotton swab dipped in water, and for older children, you can give a lollipop.

　　When the symptoms improve and the baby feels more comfortable, give multiple small amounts of electrolyte solution (sports drinks can be used instead, but if diarrhea is also present, the sports drink should be diluted before drinking), if there is no obvious nausea, vomiting, or abdominal distension, you can give light food (such as congee, rice, white bread, steamed bun) again, but avoid dairy products and greasy food (these foods can cause bloating or nausea) for two to three days.

　　First, Treatment

　　1. Treatment of the Etiology

　　Aggressive treatment of the primary disease is very important. If it is caused by intestinal or extraintestinal infection, infection should be controlled. For digestive tract malformations or mechanical intestinal obstruction, timely surgical intervention should be performed to relieve obstruction. Stop using drugs that cause vomiting and correct inappropriate feeding methods. For acute poisoning, gastric lavage should be performed promptly.

　　2. General Treatment

　　Closely observe the condition, record the intake and output, and pay attention to the characteristics of vomitus and stool. Pay attention to the position, often taking a head-high, right lateral position or supine position, with the child's head turned to one side to prevent vomitus from being inhaled into the respiratory tract. For children with severe vomiting or suspected surgical diseases, temporary fasting should be performed. For newborns with vomiting caused by swallowing amniotic fluid, a single lavage with 1% sodium bicarbonate or water can be used.

　　3. Symptomatic Treatment

　　For those with galactorrhea, it is necessary to improve the breastfeeding method, pay attention to taking the correct baby position during feeding, and after feeding, hold the baby upright on the adult's shoulder while patting the back to ensure that the gas in the stomach is fully expelled.

　　Antispasmodics (such as atropine, belladonna syrup), sedatives (such as chlorpromazine, promethazine, phenobarbital) can be used according to the situation. Metoclopramide (Antivert 2.5-5mg per dose) has central antiemetic action. It should be noted that due to the incomplete blood-brain barrier in infants, it can cause extrapyramidal symptoms. In surgical diseases such as mechanical intestinal obstruction, intestinal perforation peritonitis, and other causes of vomiting, the above drugs should be used with caution. Patients with water, electrolyte, and acid-base imbalances should be given intravenous fluid replacement to correct them. Patients with obvious abdominal distension should undergo gastric decompression.

　　4. Drug Treatment

　　Metoclopramide (Gastropulmin) used in the past has been discontinued due to its propensity to cause extrapyramidal side effects and induce torsional dystonia. In recent years, it has been found that cisapride (Prepulsid) can cause abdominal pain, diarrhea, and severe arrhythmias among other adverse reactions, and caution must be exercised when used. The currently safer and more effective antiemetic is domperidone (Motilium), which is a benzimidazole derivative with ant dopamine action. Domperidone (Motilium) can increase the tone of the lower esophageal sphincter, improve the motility of the stomach and duodenum, promote gastric emptying, and thus has a good antiemetic effect. Dosage: 0.3mg/kg per dose, 3 times a day, taken 15-30 minutes before meals. Domperidone (Motilium) acts solely on the stomach and not on the intestines, thus it has no side effects such as abdominal pain and diarrhea. Domperidone (Motilium) has peripheral action and is not easily absorbed into the brain, so it rarely causes extrapyramidal side effects. However, due to the high permeability of the blood-brain barrier in infants under 3 months old, it should still be used with caution. Other medications include chlorpromazine (Dolantin), which has sedative and antiemetic effects, dosage: 1mg/kg per dose, oral or intramuscular injection (compound Dolantin can be used).

　　5. Fluid Therapy

　　Moderate to severe vomiting often accompanied by water and electrolyte imbalance should be corrected. Such children often have acidosis, ketonemia, ketonuria, and decreased blood glucose. Glucose, alkaline solution should be administered. Correct hypoglycemia and eliminate ketonemia. Generally, intravenous fluid therapy is 30-50ml/kg per time, and a 4:3:2 solution or 1:1 with alkali solution (i.e., 10% glucose 100: 0.9% sodium chloride 100ml, 5% sodium bicarbonate 10ml) can be used. Potassium should be added appropriately after urination. In case of severe dehydration and electrolyte imbalance, refer to the results of blood biochemical tests for correction.

　　6. Diet

　　Mild cases can still eat, but attention should be paid to fluid intake to prevent dehydration. Breast milk can be fed normally, or semi-liquid food can be given, with the addition of congee and salt solution or ORS solution. For severe and frequent vomiting, short-term fasting (4-8 hours) should be given, and intravenous fluid therapy should be provided. After vomiting is controlled, normal diet should be gradually resumed.

　　7. TCM Treatment

　　Traditional Chinese medicine (TCM) treatment for pediatric vomiting is very effective. Vomiting is a common disease caused by the failure of the stomach to descend and Qi rising upwards, leading to milk and food being expelled from the stomach through the mouth. This condition has no age or seasonal restrictions, but is more prone to occur in infants and young children, especially in summer. Any external pathogens, internal injury from milk and food, fear and shock, or other zang-fu organ diseases affecting the function of the stomach, leading to Qi rising upwards, can cause vomiting. If treated promptly, the prognosis is usually good. Chronic or long-term vomiting can damage the stomach Qi, disrupt the normal appetite, and lead to fluid loss and deficiency of Qi and blood.

　　(1) Various causes can lead to vomiting: Common ones include injury to the stomach by milk and food, invasion of the stomach by external pathogens, heat accumulation in the stomach, deficiency-cold of the spleen and stomach, liver Qi attacking the stomach, and fear and shock.

　　(2) Differential diagnosis and treatment:

　　①Vomiting due to indigestion: Children have small and weak stomachs. If fed improperly, with excessive milk and food, or eating too quickly, older children may overeat cold, greasy, and difficult-to-digest foods, accumulating in the stomach, leading to blockage in the middle energizer, causing the stomach to reject food, the spleen to lose its healthy function, and the ascending and descending of Qi to be disrupted, resulting in vomiting due to the Qi rising upwards.

　　Main symptoms: The vomitus is mostly sour and smelly milk lumps or undigested food, loss of appetite for milk and food, foul breath, epigastric and abdominal distension, feeling of relief after vomiting, constipation or diarrhea with sour smell, red tongue with thick and greasy coating, slippery and rapid pulse.

　　Treatment principle: Eliminate food retention and promote digestion, harmonize the stomach and reverse the adverse flow. Formula: Modified Baohe Pill.

　　Commonly used drugs: Hoelen, Tangerine peel, Roasted Three Treasures, Amomum villosum, Raphanus sativus, Poria, Forsythia, Pinellia ternata, Ginger. Constipation: Add dried tangerine peel. Restlessness and irritability: Add Uncaria rhynchophylla, Mother of Pearl. Abdominal pain: Add Costus root, White peony root, Corydalis yanhusuo.

　　②Exogenous Vomiting: Due to improper care, invasion of external pathogens, injury to the gastrointestinal tract, and failure of the stomach to descend, vomiting occurs.

　　Commonly used drugs: Hoelen, Dendrobium, Citrus reticulata Blanco, Talcum, Poria cocos, Lonicera japonica, Houttuynia cordata, Pinellia ternata, Ginger. High fever: Add Gypsum fibrosum, Bupleurum.

　　③Gastric heat vomiting: Clinical manifestation of acute gastritis.

　　Main symptoms: Frequent vomiting, vomiting soon after eating, vomiting sour and smelly substances, dry mouth and thirst, liking cold drinks, constipation, jaundice. Red tongue, yellow fur, slippery and rapid pulse.

　　Treatment principle: Clearing heat in the stomach, harmonizing the stomach and stopping vomiting. Formula: Stomach Poria Decoction modified.

　　Commonly used drugs: Citrus reticulata Blanco, Pinellia ternata, Poria cocos, Bambusa textilis, Magnolia officinalis, Coptis chinensis, Scutellaria baicalensis, Stewed Three Herbs. Fever: Add Hoelen, Gypsum fibrosum. Dampness: Add Liuyi Powder. Abdominal pain: Add Fructus meliae, Costus laticarpus,芍药, Licorice. Constipation: Add Stewed Rhubarb.

　　④Gastric cold vomiting: Equivalent to some chronic gastritis, with a long course.

　　Main symptoms: The onset is relatively slow, the course is long, vomiting after eating for a long time, or vomiting in the morning and eating in the evening, vomiting is light, not sour or smelly, pale complexion, spirit fatigue, cold limbs, or abdominal pain, loose stools, clear urine. Pale tongue, thin white fur, weak pulse.

　　Treatment principle: Warming the middle-jiao, dispersing cold, harmonizing the stomach and reversing the qi. Formula: Dingyue Liren Decoction modified.

　　Commonly used drugs: Codonopsis pilosula, Atractylodes macrocephala, Zingiber officinale, Licorice, Clove, Evodia rutaecarpa, Citrus reticulata Blanco, Pinellia ternata, Poria cocos. Abdominal pain and loose stools, cold limbs: Add Aconitum carmichaelii, Rhizoma galangae, Cinnamomum cassia.

　　⑤Liver qi disturbing the stomach:

　　Main symptoms: Acid and bitter vomiting, or frequent belching, often exacerbated by emotional stimulation, chest and hypochondrium distension and pain, spirit depression, easy to get angry and cry, tongue edge red, thin greasy fur, pulse wiry.

　　Treatment principle: Relieving liver qi, harmonizing the stomach and reversing the qi. Formula: Liver-relieving decoction.

　　Commonly used drugs: Citrus reticulata Blanco, Bambusa textilis, Pinellia ternata, Cyperus rotundus, Magnolia officinalis, Poria cocos, Perilla leaf,芍药, Ginger. Yin injury due to damp-heat: Add Platycodon grandiflorus, Dendrobium. Vomiting yellow and bitter water: Add Bupleurum. Anxious and crying: Add Uncaria rhynchophylla, Mimaena japonica.

　　⑥Fright and vomiting:

　　Main symptoms: Vomiting clear saliva after falls and fright, pale or blue complexion, restless mind, restless sleep, or惊悸 crying, tongue and pulse without obvious abnormalities.

　　Treatment principle: Flowing pulse, regulating qi, invigorating the spleen and calming the惊. Formula: Scorpion Guanyin Powder modified.

　　Commonly used drugs: Codonopsis pilosula, Pinellia ternata, Pulsatilla chinensis, Citrus reticulata Blanco, Poria cocos, Alisma orientale, Costus laticarpus, Buthus martensii, Licorice, Periostracum cicadae (decocted last), Haematite (decocted first). Restless sleep at night: Add Uncaria rhynchophylla, Mimaena japonica.

　　II. Prognosis

　　Good prognosis for those who can remove the cause in time.