Pediatric gastrointestinal tract bleeding

　　First, the etiology

　　1. The local lesions of the gastrointestinal tract vary in the common causes of bleeding in different age groups

　　(1) Newborns:

　　①Upper gastrointestinal tract: ingestion of maternal blood, stress ulcer, neonatal natural hemorrhagic disease, lactose intolerance, etc.

　　②Lower gastrointestinal tract: necrotizing enterocolitis, intestinal duplication, intussusception, congenital megacolon.

　　(2) Infants:

　　①Upper gastrointestinal tract: ingestion of maternal blood, reflux esophagitis, stress ulcer, gastritis, hemorrhagic diseases, Mallory-Weiss syndrome.

　　② Lower gastrointestinal tract: necrotizing enterocolitis, bacterial enteritis, and intestinal obstruction affecting blood supply, such as intussusception and intestinal duplication anomalies.

　　(3) Children:

　　① Upper gastrointestinal tract: bacterial gastroenteritis, peptic ulcer disease/gastritis, reflux esophagitis, Mallory-Weiss syndrome.

　　② Lower gastrointestinal tract: anal fissure is the most common; intussusception, inflammatory bowel disease, vascular malformations, intestinal vascular dysfunction, allergic purpura, polyps, and parasitic diseases are also not uncommon.

　　(4) Adolescents:

　　① Upper gastrointestinal tract: peptic ulcer disease, inflammation, gastric fundus esophageal varices, reflux esophagitis, Mallory-Weiss syndrome, biliary bleeding, pancreatitis.

　　② Lower gastrointestinal tract: bacterial enteritis, inflammatory bowel disease, polyps, hemorrhoids.

　　2. Systemic diseases

　　Gastrointestinal bleeding is a local manifestation of systemic diseases. Blood system diseases such as leukemia, hemophilia, pernicious anemia, and primary thrombocytopenic purpura, in addition to bleeding in the skin, subcutaneous tissue, joints, and mucous membranes, may also be accompanied by gastrointestinal and urinary tract bleeding. Bone marrow examination, platelet count, peripheral blood, and coagulation time, as well as clot retraction time, can be used to confirm the diagnosis.

　　Two: Pathogenesis

　　1. Mucus damage

　　Inflammation, erosion, and ulcers of the gastrointestinal mucosa caused by various factors can lead to bleeding due to congestion and edema, red blood cell exudation, or erosion of blood vessels by ulcers. Severe infections, shock, and extensive burns can trigger stress responses, leading to ischemia of the gastric mucosa, abnormal tissue energy metabolism, or reduced renewal of gastric mucosal epithelial cells, resulting in erosion or ulcers of the gastric mucosa and bleeding. Gastrointestinal endoscopy, hard stools, and other factors can also damage the mucosa and cause bleeding.

　　2. Disruption of gastrointestinal blood circulation

　　Obstruction of intestinal circulation and return can cause marked congestion and rupture of the intestinal wall veins, leading to gastrointestinal bleeding. Conditions such as hiatal hernia and intussusception can cause this.

　　3. Increased capillary permeability

　　Infections, intoxication, hypoxia, and other factors can cause changes in the permeability of capillaries, leading to mucosal hemorrhage. Capillary lesions such as allergic purpura, vitamin C deficiency, and hereditary telangiectasia can also cause bleeding.

　　4. Bleeding

　　Dysfunction of coagulation factors, thrombocytopenia, or dysfunction, and other factors can cause gastrointestinal bleeding. Conditions such as hemophilia and vitamin K deficiency can also lead to bleeding.

　　Children with gastrointestinal bleeding often have small amounts of bleeding that can lead to anemia. Large and rapid bleeding can lead to hemorrhagic shock, and complications such as azotemia may occur. Once symptoms are detected, timely treatment is essential.

　　One: Hematemesis, melena, and hematochezia

　　1. Hematemesis represents bleeding above the pylorus. The color of hematemesis depends on whether the blood has been acted upon by acidic gastric juice. If the amount of bleeding is large and the speed is fast, and the blood stays in the stomach for a short time, such as bleeding from esophageal varices, the hematemesis is often dark red or bright red. Conversely, due to the formation of methemoglobin by the action of gastric acid, it may appear as coffee-colored or brownish. Hematemesis is often accompanied by melena, which may or may not be accompanied by hematemesis.

　　2. Melena represents bleeding from the upper gastrointestinal tract or small intestine, with the color of the feces being black and tarry. The color of the melena is affected by the duration of blood staying in the intestines. When the amount of bleeding is large and the speed is fast, the peristalsis is hyperactive, and the feces can be dark red or even bright red, resembling lower gastrointestinal bleeding; conversely, in cases of small amount of bleeding in the jejunum and ileum, if the amount of bleeding is not much and the blood stays in the intestines for a long time, it can also be manifested as melena.

　　3. Hematochezia refers to the feces being bright red or dark brown, with the bleeding site mostly located in the colon. However, in cases of massive bleeding in the upper gastrointestinal tract, due to the mild laxative effect of blood, the excretion time is shortened, making the feces bright red.

　　The characteristics of feces are also affected by the amount and speed of bleeding. In cases of large amount of bleeding and fast bleeding speed, the feces are in a loose paste-like state; in cases of small amount of bleeding and slow bleeding, the feces are formed.

　　II. Other manifestations

　　Other clinical manifestations vary with the amount of bleeding, bleeding site, and bleeding speed. In cases of small amount of bleeding and short bleeding time, there may be no symptoms; in cases of long-term bleeding, there may be manifestations of chronic anemia due to bleeding, such as pale complexion, fatigue, dizziness, decreased appetite, etc.; and short-term massive bleeding can cause hypovolemic shock, manifested as:

　　1. Peripheral circulatory disorder

　　Short-term massive bleeding can cause a rapid decrease in circulating blood volume, insufficient venous return blood volume, reduced cardiac output, and symptoms such as dizziness, fatigue, palpitations, sweating, dry mouth, pale skin, and cold and damp.

　　2. Fever

　　The mechanism of fever is not yet clear, and it may be due to the accumulation of blood in the intestinal cavity, absorption of decomposition products of hemoglobin, decreased blood volume, peripheral circulatory failure, and other factors affecting the thermoregulatory center, leading to fever.

　　3. Azotemia

　　After a large amount of gastrointestinal bleeding, blood urea nitrogen often increases, and the first to appear is intestinal azotemia, which is due to the decomposition and absorption of hemoglobin in the intestines after gastrointestinal bleeding, causing an increase in blood urea nitrogen. Intestinal azotemia appears early, reaching a peak in 24-48 hours, and returns to normal in 3-4 days; when bleeding leads to peripheral circulatory failure and reduces renal blood flow and glomerular filtration rate, it produces pre-renal azotemia, which quickly returns to normal after correcting shock; persistent shock can cause tubular necrosis in the kidneys, leading to renal azotemia, even if the shock is corrected, the blood urea nitrogen does not decrease.

　　Prevent local gastrointestinal lesions such as esophageal varices, esophagitis, gastric and duodenal ulcers, acute hemorrhagic necrotizing enteritis, etc.; prevent infectious diseases such as sepsis, enteritis, dysentery; prevent gastrointestinal bleeding caused by vitamin K deficiency and allergic purpura.

　　1. Hematological examination

　　Blood routine, platelets, coagulation time, thrombin and prothrombin time, liver function test.

　　2. Routine fecal examination

　　Occult blood test and stool culture.

　　3. Bone marrow examination

　　4. Swallowing thread method

　　It can roughly determine the location of upper gastrointestinal bleeding. The method is to use a thick white thread, about 2 meters long, with a small sugar ball tied at one end, let the child swallow it, and the other end is fixed on the cheek with adhesive tape. With the peristalsis of the gastrointestinal tract, the white thread will gradually descend to the duodenum. After 24 hours, the thread should be gently pulled out to avoid injury to the mucosa of the gastrointestinal tract and cause false phenomena. Normally, it is white-yellow, if there is bleeding in the stomach, it is white-red-yellow, and if there is bleeding in the duodenum, it is white-yellow-red. The bleeding location is judged according to the staining of the thread. This examination requires the cooperation of the child, otherwise, the thread is difficult to be successfully performed as it may be bitten off.

　　5. X-ray barium meal and barium enema examination

　　Generally, it is required to be performed after the condition is stable, blood pressure is restored, and cardiac function improves, but if there is suspected esophageal varices bleeding, a barium swallow examination can be performed at the time of bleeding for diagnosis. Barium meal and air double contrast are helpful for examining the stomach, duodenum, and small intestine for diseases such as peptic ulcers, tumors, intestinal stenosis, etc. Barium enema or air double contrast can make a diagnosis for rectal, sigmoid colon polyps, ulcerative colitis, tumors, intussusception, etc., and can also observe the position of the colon, assist in the diagnosis of malrotation of the intestine.

　　1. Fasting

　　Patients with massive bleeding, shock, nausea, and vomiting should be fasting, especially for patients with massive upper gastrointestinal bleeding, such as bleeding from esophageal varices, severe ulcers with vascular residual bleeding accompanied by vomiting and hematochezia, should be fasting. Parenteral nutrition and fluid and electrolyte balance should be maintained, and fresh concentrated red blood cells and plasma should be administered if necessary.

　　2. Liquid diet

　　After 24 hours of bleeding cessation, without nausea and vomiting, blood pressure is stable, heart rate is stable, and hemoglobin shows no significant change, patients can be given liquid diet with cool temperature, mainly rice gruel, and can also consume a moderate amount of milk. Milk can neutralize stomach acid, which is beneficial for hemostasis, but due to the gas production of milk, it is recommended to take small amounts in multiple meals, less than 100mL per meal, and patients with liver cirrhosis and bleeding should not consume milk to prevent the occurrence of hepatic coma and exacerbation of abdominal distension. Other foods such as lotus root starch can also be provided. During this period, 5-6 meals can be taken daily, about 2-3 days, and still need intravenous fluid replacement and electrolytes. For patients with severe anemia, fresh concentrated red blood cells and plasma can be administered. For patients who have stopped bleeding for 4-6 days, in addition to providing sufficient fluids and electrolytes, the diet should still be mainly liquid food such as rice gruel, and meat soup can also be provided, taken in small amounts in multiple meals, 100-150mL per meal, 5-6 meals per day, this period is about 5-7 days.

　　3. Semi-liquid diet

　　Patients whose bleeding has stopped and whose condition is stable can be given non-irritating, low-fiber semi-liquid diet. During this period, foods such as thin rice porridge, fine noodle soup, steamed eggs, sesame paste, etc., can be provided, about 150-200g each time, and the diet should not be too sweet, this period is about 7-10 days. During this period, 4-5 meals can be taken daily. After no discomfort, the amount of food can be appropriately increased, each time less than 250g.

　　1. Treatment

　　The treatment principles for gastrointestinal bleeding in children are: quickly stabilize the vital signs of the child; assess the severity of bleeding; determine the bleeding focus; clarify the cause of bleeding, treat the root cause; formulate special treatment methods; and surgical treatment.

　　1. Rapidly stabilize the child's vital signs

　　(1) General first aid measures:

　　① Absolute bed rest: Lie on the side with the pillow removed, keeping the airway open. Avoid inhaling blood into the trachea during vomiting, causing asphyxia, and maintain tranquility.

　　② Refrain from eating: The period of fasting should last for 24 hours after bleeding stops.

　　③ Oxygen therapy: After massive hemorrhage, blood pressure decreases, hemoglobin levels decrease, and its oxygen-carrying function decreases. Oxygen therapy is provided to ensure oxygen supply to vital organs in the case of anemia.

　　④ Strictly observe the condition: Observe the patient's pulse, blood pressure, respiration, body temperature, urine output, changes in consciousness, limb temperature, skin and nail bed color, peripheral venous filling status; the amount and color of vomited blood and black stools; if necessary, measure the central venous pressure: the normal value is 0.59 to 1.18kPa (6 to 12cmH2O), below normal suggests insufficient blood volume, above normal suggests excessive fluid volume, heart failure; measure blood routine, hematocrit, coagulation time, thrombin, and prothrombin time; liver and kidney function, blood electrolyte measurements.

　　(2) Active blood volume supplementation: In cases of active massive hemorrhage, blood transfusion or intravenous fluid resuscitation should be given promptly to maintain blood volume. Generally, according to the estimated amount of blood loss, 20ml/kg of physiological saline or 5% glucose physiological saline should be infused within the first half hour. Simple crystalloid fluids are quickly transferred to the extracellular space, so it is advisable to use colloidal fluids in moderate amounts. For example, whole blood, plasma, or dextran, commonly using medium molecular weight dextran, can increase osmotic pressure, expand blood volume, and have a relatively long-lasting effect, with a dose of 15 to 20ml/kg.

　　Indications for blood transfusion: ① Heart rate > 110/min; ② Red blood cells < 3×10^12/L; ③ Hemoglobin < 70g/L; ④ Systolic blood pressure < 12kPa (90mmHg). Liver cirrhosis patients should receive fresh blood, as stored blood contains a high nitrogen content, which can induce hepatic encephalopathy. In patients with portal hypertension, prevent excessive and rapid blood transfusion to increase portal vein pressure and trigger further hemorrhage. The amount of blood transfusion and fluid infusion should not be excessive, and it is best to adjust the infusion rate and amount according to the central venous pressure (CVP). CVP can reflect blood volume and right heart function; CVP < 0.49kPa (< 5cmH2O), indicating that the fluid intake has basically met the needs.

　　2. Evaluate the severity of hemorrhage

　　(1) Mild hemorrhage: The amount of blood loss reaches 10% to 15% of blood volume, with normal heart rate, blood pressure, hemoglobin, red blood cell count, and hematocrit. It can also be manifested as increased pulse rate, slightly cool extremities, decreased blood pressure, and decreased pulse pressure.

　　(2) Moderate hemorrhage: The amount of blood loss accounts for 20% of blood volume, manifested as thirst, significantly increased pulse rate, cold extremities, oliguria, decreased blood pressure, and decreased pulse pressure. From lying to sitting, the pulse rate increases ≥20/min, and blood pressure decreases ≥10mmHg, with an urgent indication for blood transfusion.

　　(3) Severe hemorrhage: The amount of blood loss accounts for 30% to 40% of blood volume, manifested as thirst, irritability, pale complexion, cold extremities, cyanosis, skin mottling, thin and rapid pulse, marked oliguria, and decreasing blood pressure. Hemoglobin is below 70g/L, red blood cell count below 3×10^12/L, and hematocrit below 30%.

　　3. Determine the bleeding focus

　　Based on the medical history, clinical manifestations, signs, and auxiliary examinations, the bleeding site can be estimated, such as hematemesis with jaundice, spider nevi, splenomegaly, abdominal wall varices, and ascites, abnormal liver function, and a protein electrophoresis showing a significant increase in λ-globulin, with a rapid result in the bromosulfophthalein sodium test and indocyanine green test, it should be considered that there is bleeding due to esophageal and gastric variceal rupture; gastroscopy can make an accurate diagnosis.

　　4. Determine the cause of bleeding and treat according to the cause

　　If the etiology is clear, timely etiological treatment should be provided. For example, if the gastrointestinal mucosal lesions are caused by drugs, the drugs should be discontinued promptly; vitamin K deficiency bleeding should be supplemented with vitamin K; for conditions such as portal hypertension, ulcer disease with perforation, etc., early surgical treatment should be performed; for diseases of the blood system, drugs to correct coagulation and anticoagulation mechanisms should be administered, such as batroxobin, lyophilized thrombin complex.

　　5. Formulate special treatment methods

　　Gastrointestinal bleeding is divided into non-variceal bleeding and variceal bleeding, and different treatment methods are adopted according to different types.

　　(1) Non-vascular gastrointestinal bleeding (ulcerative bleeding):

　　① Inhibition of gastric acid secretion: If the child only has bleeding without hemodynamic changes and the bleeding can stop spontaneously, only acid-suppressing drugs are needed. The hemostatic effect of body fluids and platelets can only be exerted when pH is greater than 6.0. Therefore, by neutralizing gastric acid and reducing the inhibition of platelet hemostasis by gastric acid, effective control of bleeding from peptic ulcers can be achieved. In addition, controlling the acidity of gastric juice can reduce the backdiffusion of hydrogen ions and inhibit the activity of pepsin, thereby reducing the damage to the gastric mucosa. Clinically, H2 receptor antagonists such as cimetidine (Tegamet) are commonly used at a dose of 25-30mg/kg daily, administered intravenously twice daily for 2-3 days, then switched to oral administration after the condition stabilizes, for peptic ulcer disease for 6 weeks, for erosive gastritis for 4 weeks, with a hemostasis rate of 86%-90%; or ranitidine at a dose of 6-7.5mg/kg, or famotidine at a dose of 0.8-1.0mg/kg. Proton pump inhibitors such as omeprazole are administered at a dose of 0.8-1mg/kg intravenously; or 0.6-0.8mg/kg in the morning, taken as a single dose, for a course of 4 weeks.

　　② Endoscopic treatment: Endoscopic treatment should be performed when there is acute, persistent, or recurrent bleeding in children, with hemodynamic changes, and when the etiology is unknown.

　　A. Indications: Active bleeding in the ulcer lesion, with blood clots adhering or exposed blood vessels; if the base of the ulcer is clean and the blood crust is flat, there is no need for urgent endoscopic treatment.

　　B. Methods: Local application of hemostatic drugs, local injection, electrocoagulation, and thermal coagulation for hemostasis. Local application of norepinephrine causes vasoconstriction of the local vessel wall, constriction of the blood vessels around the bleeding surface, and promotes blood coagulation; injection therapy involves injecting epinephrine or sclerosing agents around the blood vessels to cause tissue edema, compress the bleeding blood vessels, and stop bleeding; the principle of thermal coagulation for hemostasis is to utilize the generated heat to coagulate tissue proteins and stop bleeding. In addition, there are laser photocoagulation and microwave hemostasis.

　　③Vascular embolization therapy: After selective arterial angiography is confirmed, the catheter can be inserted into the artery to inject artificial emboli to embolize the blood vessels to achieve hemostasis, for example, for duodenal bulb ulcer bleeding, choose to embolize the superior duodenal artery, which can often stop the bleeding, with a hemostasis success rate of 65% to 75%. However, arterial embolization for hemostasis may sometimes cause serious consequences such as infarction or necrosis of the organ supplied by the artery, so it should be strictly controlled for indications.

　　(2) Angiogenic gastrointestinal bleeding:

　　①Drugs: The drugs that reduce portal pressure reduce the blood flow at the bleeding site, creating good conditions for the coagulation process and achieving hemostasis. The drugs that reduce portal pressure are mainly divided into two categories:

　　A, Vasoconstrictor drugs:

　　a, Vasopressin (antivascular pressor) and its derivatives: They can contract the small visceral arteries and pre-capillary sphincters, reduce the blood flow of the viscera, thereby lowering the pressure in the portal system and varicose veins; used for portal hypertension and esophageal-gastric variceal rupture bleeding. The commonly used dose for adults is 0.2U/min, intravenous infusion, and if ineffective, increase to 0.4-0.6U/min. When the dose exceeds 0.8U/min, the efficacy no longer increases while adverse reactions increase. Generally, it is not necessary to use a first dose, and stop the medication after maintaining 0.1U/min for 12 hours after hemostasis. Adverse reactions include: increased blood pressure, angina, arrhythmia, abdominal pain, vomiting, frequent defecation, and even complications of intestinal ischemia and necrosis, exacerbating liver and kidney function damage, etc. To reduce adverse reactions, it can be used in combination with nitroglycerin.

　　b, Somatostatin and its derivatives: They have the effects of inhibiting the secretion of gastric acid and pepsin, reducing the blood flow of the main portal vein, and protecting gastric mucosal cells. They are effective and safe drugs for upper gastrointestinal bleeding, especially for bleeding due to esophageal variceal rupture. There are two commonly used types: somatostatin (Stanozolol) 5?g/kg + 5ml normal saline, intravenous slow injection for 3-5 minutes, followed by continuous intravenous infusion at a rate of 5?g/(kg·h) for 12 hours after immediate intravenous infusion (adults 3000?g + 500ml 5% glucose intravenous infusion to maintain 12 hours), continue treatment for 24-48 hours after hemostasis to prevent recurrence of bleeding; adult octreotide, 0.1mg/time, intravenous or subcutaneous injection, 3 times/d, or 0.1mg first intravenous injection, then 0.3mg intravenous infusion, 25?g/h, maintaining for 12 hours. The dosage for children is calculated according to body weight. Adverse reactions: mild, occasional palpitations, dizziness, nausea, increased frequency of bowel movements, etc., symptoms disappear after slowing down the injection rate or stopping the injection.

　　B, Vasodilators:

　　a、Nitroglycerin: usually used in combination with posterior pituitary extract, it can dilate arteries and veins, reduce the cardiac load, decrease the portal blood flow, and lower the portal pressure.

　　b、Phentolamine: as an alpha-adrenergic receptor blocker, it can directly act on the alpha1 receptors of the portal venous vascular system of the liver, causing the portal veins to dilate and the portal pressure to decrease.

　　②Endoscopic treatment: including sclerotherapy and endoscopic variceal ligation (EVL).

　　A. Sclerotherapy: is currently the best established treatment method for esophageal variceal bleeding. This method has been proven to be safe and effective, and is inexpensive, with a wide range of applications and simple operation. It involves injecting sclerosing agents or vasoconstrictors through the veins or near the veins, causing tissue edema, compressing bleeding vessels, leading to thickening of the vascular wall, coagulation and necrosis of surrounding tissues, and thrombosis of varicose veins and fibrous tissue proliferation, thus stopping bleeding. Currently commonly used sclerosing agents include: 5% sodium lauryl sulfate, 1% to 2% ethoxysclerol, absolute ethanol, etc. Complications: chest pain, low fever, bleeding at the injection site, esophageal ulcer, esophageal stricture, etc.

　　B. Venous ligation: is a new endoscopic treatment method for esophageal varices. This technique is similar to the ligation method for hemorrhoids. During the operation, the varicose veins are drawn into the elastic band device at the front end of the endoscope, and the tie line is tightened through the biopsy channel to tie and tie the varicose veins at the root. Advantages. Few complications, and fewer treatment sessions are needed to make the varicose veins disappear. Disadvantages: The operation is complicated and difficult to master.

　　③ Three-bag tube compression hemostasis: is one of the most effective hemostatic methods for treating esophageal and gastric fundus variceal bleeding, mainly used for those who fail to respond to medical treatment or have no surgical indications. It is usually performed within 48 hours after the placement of the three-bag tube for venous ligation or sclerotherapy. Complications include aspiration pneumonia, even esophageal rupture, and asphyxiation.

　　6. Surgical operation

　　Children with gastrointestinal bleeding should be treated conservatively as much as possible. Surgical treatment requires at least a rough determination of the bleeding site to determine the surgical approach. Emergency surgery has a high mortality rate and must be handled with caution. Indications include:

　　(1) When bleeding does not stop after 24 hours of medical treatment and endoscopic treatment.

　　(2) Severe hematemesis or melena, accompanied by hypotension and recurrent bleeding.

　　(3) When the amount of bleeding is large, reaching more than 25% of the blood volume, and comprehensive抢救 measures in internal medicine are ineffective.

　　(4) Gastrointestinal necrosis, perforation, strangulating obstruction, repeated malformations, and Meckel's diverticulum.

　　II. Prognosis

　　Recurrent gastrointestinal bleeding often affects the growth and development of children, and a good prognosis is possible if the cause is cleared in time. If it is massive and rapid bleeding and the treatment is not timely, it often leads to death. The prognosis varies depending on the primary disease, which may be a blood system disease (leukemia, malignant anemia, or DIC).