Gastrointestinal bleeding is one of the most common clinical emergencies. The entire GI tract, including the esophagus, stomach, duodenum, jejunum, ileum, cecum, colon and rectum, can bleed for various reasons. The causes of gastrointestinal bleeding in newborns are very different from those in adults. Etiology Gastrointestinal bleeding in newborns can be caused by lesions of the GI tract itself, such as malformation, inflammation, mechanical injury, and vascular lesions, or by systemic lesions such as hematologic diseases, hypoxia, infection, and hypothermia. The clinical manifestations of GI bleeding depend on the nature and location of the bleeding lesion, the amount and rate of blood loss, and are also related to the patient’s general condition. Diagnosis The difficulty in the diagnosis of gastrointestinal bleeding in newborns lies in the diagnosis of the cause and site of bleeding. 1. Judgment of the amount and site of neonatal hemorrhage The combination of the mode of bleeding, systemic manifestations, and changes in signs during treatment can determine whether the bleeding continues or worsens, and whether the bleeding site is in the upper or lower gastrointestinal tract. 2.Etiology judgment is based on the preliminary judgment of the accompanying symptoms of bleeding and the presence or absence of the original disease, such as the presence or absence of neonatal hypoxia-ischemia, severe pneumonia, cold stimulation, the presence or absence of accompanying bilious vomiting, the presence or absence of severe infection, the presence or absence of abdominal distension, etc. to analyze the cause. 3. Special diagnostic methods include X-ray radiography, gastrointestinal imaging, endoscopy and radionuclide imaging, etc. Differential diagnosis 1. Stress ulcer is the main cause of upper gastrointestinal bleeding in newborns. The common high-risk factors are: intrauterine distress and birth asphyxia, neonatal ischemic-hypoxic encephalopathy, neonatal severe pneumonia and severe infection, premature low birth weight infants, sclerosis and shock. Hemorrhage is mainly extensive bleeding from the gastric mucosa and the amount is large. 2. Neonatal hemorrhage refers to the natural bleeding caused by temporary coagulation disorder within 2-5 days of birth. It is caused by insufficient intestinal vitamin K synthesis due to immature liver function and lack of normal flora in the intestine of newborns. Supplementation of vitamin K and symptomatic treatment can cure it. The main manifestation of necrotizing small intestine colitis is that infection plays a major role in the pathogenesis of the disease, mostly in premature and low birth weight infants, with abdominal distension, diarrhea, vomiting and blood in the stool as the main manifestation, severe symptoms of infection poisoning, often complicated by sepsis, shock, peritonitis, intestinal perforation, etc. X-ray plain examination can be seen in the intestines of general distension, intestinal tube shape stiffness, intestinal wall cystic pneumatosis, portal venous pneumatosis and other characteristic signs. The signs of pneumoperitoneum can be seen on X-ray. In recent years, ultrasonography is considered more sensitive than X-ray for pneumoperitoneum, intrahepatic pneumoperitoneum, pneumoperitoneum, etc., and has become an important diagnostic tool for this disease. 4.hypertrophic pyloric stenosis The bleeding is not much, mostly seen in full-term infants, the ratio of male to female is 4:1. vomiting starts around the second week after birth, vomiting is persistent, progressive, and gradually develops into jet vomiting. The vomit is milk and milk lumps, in large amounts, with a sour odor. When vomiting is severe enough to cause gastric mucosal damage and bleeding, it may appear as vomiting coffee-like material. On abdominal examination, there are obvious gastric pattern and gastric peristaltic waves, and a hard swelling of olive size can be palpated in the right rib margin under the rectus abdominis muscle, which is a hypertrophic pyloric sphincter. Barium meal examination reveals an enlarged stomach, prolonged gastric emptying time, typical beak-like changes in the pylorus and a narrow and prolonged pyloric canal. Ultrasonography can directly see the hypertrophic pyloric sphincter, and the diagnosis is made when the thickness of the pyloric muscle exceeds 4 mm or the length of the pyloric duct exceeds 14 mm. 5. Esophageal hiatal hernia It is a congenital developmental defect of the diaphragm that allows part of the stomach to enter the thoracic cavity through the esophageal hiatal hernia. Esophageal hiatal hernia is divided into sliding esophageal hernia, paraesophageal hernia and mixed type. 85% of the affected children develop vomiting within the first week after birth, and 10% develop within 6 weeks after birth. The vomit is not vomited in the standing position, but it is obvious when lying down and can be jet vomiting. Gastric ulceration may occur in paraoesophageal hernia, and occasionally gastric necrosis may occur, requiring emergency surgical management. Diagnosis mainly relies on X-ray examination, barium meal found diaphragmatic gastric bubble shadow or gastric mucosal shadow can be diagnosed. 6, poor intestinal rotation combined with intestinal torsion Generally, vomiting starts 3-5 days after birth, vomiting can be intermittent, sometimes light and sometimes heavy, vomit is milk, containing bile, after birth, there is fetal stool discharge. If gastrointestinal bleeding occurs, suggesting intestinal torsion necrosis, followed by intestinal perforation and peritonitis, positive peritoneal irritation sign, toxic shock, etc. X-ray standing film can be seen in the dilated stomach and duodenum, with double bubble sign, jejunum and ileum with little or no gas, barium enema shows that most of the colon is located in the left abdomen, the cecum is located in the left upper abdomen or mid abdomen to confirm the diagnosis. 7, gastric torsion can be divided into organ axis type torsion and tethered axis type torsion, the organ axis type is common, vomiting coffee-like material as the main bleeding manifestation, the diagnosis mainly relies on X-ray examination, barium meal found that the gastric mucosa cross distribution, can be diagnosed. 8, Merkel diverticulum Merkel diverticulum is a malformation formed due to abnormal development of the yolk tube during the embryonic period, and the incomplete closure of the ileocecal end of the yolk tube forms Merkel diverticulum, which is a true diverticulum at the end of the ileum and is mostly located in the opposite edge of the mesentery within 100 cm of the terminal ileum. The diverticulum often has ectopic gastric mucosa, pancreatic tissue, and duodenal mucosa, and inflammatory bleeding can occur, mainly in the form of large amounts of blood in the stool. 99mTc-scintigraphy and ultrasonography can be diagnosed. It mostly develops within 2 years of age, but is rare in the neonatal period. 9, intestinal loop The main manifestations are paroxysmal abdominal pain, jam-like blood stool, abdominal mass, vomiting, concentric circle sign and sleeve sign found by ultrasonography, cup-shaped shadow found by X-ray enema can be diagnosed, rare in neonates. Treatment 1.Conventional treatment should be based on close monitoring of vital signs and active symptomatic hemostasis, including fasting to reduce gastrointestinal irritation, application of vitamin K1, meclizine, thrombin, lithotripsy and other drugs, and blood transfusion if necessary. 2. Etiological treatment includes reducing stress factors, surgical correction of digestive tract deformities, etc.