Gastrointestinal bleeding

　　Gastrointestinal bleeding can be caused by factors such as inflammation of the gastrointestinal tract itself, mechanical injury, vascular lesions, tumors, etc., or due to the involvement of the gastrointestinal tract by lesions of adjacent organs and systemic diseases.

　　(I) Etiology of upper gastrointestinal bleeding

　　1. Esophageal diseases: Esophagitis (reflux esophagitis, esophageal diverticulitis), esophageal cancer, esophageal ulcer, esophageal gastroesophageal mucosal laceration, injury caused by instrumental examination or foreign bodies, radiation injury, chemical injury caused by strong acid and alkali.

　　2. Gastric and duodenal diseases: Peptic ulcer, acute and chronic gastritis (including drug-induced gastritis), gastric mucosal prolapse, gastric cancer, acute gastric dilatation, duodenitis, residual gastritis, residual gastric ulcer or cancer, as well as lymphoma, leiomyoma, polyps, sarcoma, hemangioma, neurofibroma, diaphragmatic hernia, gastric volvulus, diverticulitis, hookworm disease, etc.

　　3. Ulcers in the jejunum after gastrointestinal anastomosis.

　　4. Portal hypertension, rupture of the esophageal gastric fundus venous curve bleeding, portal hypertension-induced gastric disease cirrhosis, portal vein inflammation or thrombosis causing portal vein obstruction, hepatic vein obstruction (Budd-Chiari syndrome).

　　5. Diseases of adjacent organs or tissues to the upper gastrointestinal tract:

　　(1) Biliary hemorrhage: Biliary or gallbladder stones, biliary ascaridiasis, biliary or gallbladder disease, liver cancer, liver abscess or liver vascular lesions rupture.

　　(2) Pancreatic diseases involving the duodenum: Pancreatic abscess, pancreatitis, pancreatic cancer, etc.

　　(3) Rupture of the thoracic or abdominal aortic aneurysm into the gastrointestinal tract.

　　(4) Mediastinal tumor or abscess breaking into the esophagus.

　　6. Hemorrhage in the gastrointestinal tract in systemic diseases

　　(1) Hematological diseases: Leukemia, aplastic anemia, hemophilia, etc.

　　(2) Uremia.

　　(3) Connective tissue disease: Vasculitis.

　　(4) Stress ulcer: Severe infection, surgery, trauma, shock, adrenocortical glucocorticoid therapy, and stress states caused by certain diseases such as cerebrovascular accidents, pulmonary heart disease, severe heart failure, etc.

　　(5) Acute infectious diseases: Epidemic hemorrhagic fever, leptospirosis.

　　(Two) Etiology of Lower Gastrointestinal Bleeding

　　1. Anal Canal Diseases: Hemorrhoids, anal fissure, anal fistula.

　　2. Rectal Diseases: Rectal injury, non-specific proctitis, tuberculous proctitis, rectal tumor, rectal carcinosarcoma, adjacent malignant tumors or abscesses invading the rectum.

　　3. Colonic Diseases: Bacterial dysentery, amebic dysentery, chronic non-specific ulcerative colitis, diverticula, polyps, cancer, and vascular malformations.

　　4. Small Intestine Diseases: Acute hemorrhagic necrotizing enteritis, intestinal tuberculosis, Crohn's disease, jejunitis or ulcer, intussusception, small intestinal tumor, gastrointestinal polyps, small intestinal hemangioma, and vascular malformations.

　　The clinical manifestations of gastrointestinal bleeding depend on the nature, location, amount, and speed of bleeding, as well as the patient's age, heart and kidney function, and other systemic conditions.

　　One, hemorrhagic peripheral circulatory failure: Massive gastrointestinal bleeding leads to acute peripheral circulatory failure. If the bleeding is not stopped or treatment is not timely, it can cause a decrease in tissue blood perfusion and cellular oxygen consumption, which can lead to hypoxia, metabolic acidosis, and the accumulation of metabolic products. This can cause peripheral vasodilation, extensive damage to capillaries, and a large amount of body fluid congestion in the abdominal cavity, bones, and surrounding tissues. This results in a sharp decrease in effective blood volume, seriously affecting the blood supply to the heart, brain, and kidneys, and finally leading to irreversible shock and death.

　　Two, azotemia: It can be divided into three types: enterogenous, renal, and pre-renal azotemia.

　　Three, fever: Most patients with massive bleeding have low fever within 24 hours after bleeding.

　　The most serious is asphyxia, because upper gastrointestinal bleeding can manifest as hematemesis and black stools. If hematemesis blocks the trachea, asphyxia will occur.

　　Smoking with gastrointestinal bleeding can cause bronchitis and pneumonia. It is recommended to quit smoking as soon as possible. Currently, anti-inflammatory and hemostatic drugs can be taken for treatment. While taking medication, patients should drink plenty of water and avoid spicy, greasy, and hard foods.

　　The clinical manifestations of gastrointestinal bleeding depend on the nature, location, amount, and speed of bleeding, as well as the patient's age, heart and kidney function, and other systemic conditions. Acute massive bleeding is usually manifested as hematemesis; chronic small amount of bleeding is shown by positive occult blood in feces; when the bleeding site is above the Treitz ligament of the jejunum, the clinical manifestation is hematemesis. If the blood remains in the stomach for a long time after bleeding, it becomes acidic hemoglobin due to the action of gastric acid and presents as coffee-colored. If the bleeding is fast and the amount is large, the color of hematemesis is bright red. Black stools or tarry stools indicate that the bleeding site is in the upper gastrointestinal tract. However, if the bleeding from the duodenal site is too fast, the stool color may turn purple due to short停留 time in the intestines. When bleeding occurs in the right half of the colon, the stool color is bright red. In cases of small amount of渗血 caused by lesions in the jejunum, ileum, and right half of the colon, black stools may also occur.

　　Large-scale bleeding in the upper gastrointestinal tract can lead to acute peripheral circulatory failure. Excessive blood loss, uncontrolled bleeding, or untimely treatment can cause a decrease in tissue blood perfusion and cellular hypoxia in the body. Subsequently, due to hypoxia, metabolic acidosis, and the accumulation of metabolic products, peripheral vascular dilation, widespread damage to capillaries, and a large amount of body fluid congestion in the abdominal cavity, bones, and surrounding tissues can occur, leading to a sharp decrease in effective blood volume, seriously affecting the blood supply to the heart, brain, and kidneys, ultimately forming an irreversible shock that leads to death. During the development of peripheral circulatory failure around bleeding, clinical symptoms such as dizziness, palpitations, nausea, thirst, blurred vision, or fainting may occur; the skin may appear pale and moist and cold due to vasoconstriction and insufficient blood perfusion; after pressing the nail bed, it may appear pale and not recover for a long time. There is poor venous filling, and the superficial veins are often sunken. Patients may feel fatigue and weakness, and further symptoms such as lassitude, restlessness, and even delayed reaction and confusion may occur. Elderly organs have low reserve function, and in addition, elderly people often have cerebral arteriosclerosis, hypertension, coronary heart disease, chronic bronchitis, and other chronic diseases. Even with a small amount of bleeding, it can cause multiple organ dysfunction and increase the risk of death.

　　General condition

　　The estimation of blood loss is extremely important for further treatment. Generally, daily blood loss of more than 5ml can result in a positive occult blood test, and more than 50 to 100ml can lead to black stools. Estimating blood loss based on the amount of vomited or bloody stools is often not very accurate because vomited and bloody stools often contain gastric contents and feces, and on the other hand, some blood may still be stored in the gastrointestinal tract and has not been excreted. Therefore, judgments can be made based on the changes in peripheral circulation caused by a decrease in blood volume.

　　With a small amount of blood loss, less than 400ml, there is a slight reduction in blood volume, which can be compensated by tissue fluid and spleen stored blood. The blood circulation volume improves within 1 hour, so there may be no自觉 symptoms. When symptoms such as dizziness, palpitations, cold sweat, fatigue, and dry mouth occur, it indicates acute blood loss of more than 400ml; if there are symptoms such as fainting, cold extremities, oliguria, and restlessness, it indicates a large amount of bleeding, with blood loss of at least 1200ml. If bleeding continues, in addition to fainting, there may be shortness of breath and anuria, indicating that acute blood loss has reached more than 2000ml.

　　Pulse

　　The change in pulse is an important indicator of blood loss degree. During acute gastrointestinal bleeding, blood volume decreases sharply, and the initial compensatory function of the body is to increase heart rate. The reflex spasm of small blood vessels causes stored blood in the blood sinuses of the liver, spleen, and skin to enter the circulation, increasing the return blood volume and adjusting the effective blood circulation volume in the body to ensure blood supply to important organs such as the heart, kidneys, and brain. Once the body's compensatory function is insufficient to maintain effective blood volume due to excessive blood loss, it may enter a shock state. Therefore, when there is a large amount of bleeding, the pulse is fast and weak (or thin), and the pulse rate exceeds 100 to 120 times per minute, indicating blood loss of 800 to 1600ml; when the pulse is extremely faint and even unrecognizable, blood loss has reached more than 1600ml.

　　In some patients, after bleeding, both pulse and blood pressure may be close to normal when lying flat, but when the patient sits or semi-recumbent, the pulse will increase rapidly, accompanied by dizziness and cold sweat, indicating a large amount of blood loss. If there is no change in the above-mentioned symptoms after changing the position, and central venous pressure is normal, it can be ruled out that there has been excessive bleeding.

　　Three, Blood Pressure

　　Changes in blood pressure, like pulse, are reliable indicators for estimating blood loss.

　　When acute blood loss exceeds 800ml (20% of total blood volume), systolic blood pressure may remain normal or slightly elevated, with a reduced pulse pressure. Although blood pressure is still normal at this time, it has entered the early stage of shock, and blood pressure dynamics should be closely observed. When acute blood loss is between 800 and 1600ml (20% to 40% of total blood volume), systolic blood pressure may drop to 9.33 to 10.67kPa (70 to 80mmHg), with a small pulse pressure. When acute blood loss exceeds 1600ml (40% of total blood volume), systolic blood pressure may drop to 6.67 to 9.33kPa (50 to 70mmHg), and in more severe bleeding, blood pressure may drop to zero.

　　Occasionally, some patients with severe gastrointestinal bleeding may not have blood excreted from the gastrointestinal tract, but only present with shock. At this time, attention should be paid to excluding cardiogenic shock (acute myocardial infarction), infectious or allergic shock, as well as non-gastrointestinal internal hemorrhage (ectopic pregnancy or aortic aneurysm rupture). If intestinal sounds are active and there is blood in the stool upon rectal examination, it suggests gastrointestinal bleeding.

　　Four, Blood Picture

　　Hemoglobin measurement, red blood cell count, and hematocrit can help estimate the extent of blood loss. However, in the early stages of acute blood loss, due to compensatory mechanisms such as blood concentration and redistribution, these values may remain unchanged temporarily. Generally, it takes 3 to 4 hours for tissue fluid to infiltrate into the vascular system to replenish blood volume, at which time hemoglobin levels begin to drop, reaching a maximum dilution after an average of 32 hours after bleeding. If a patient has no anemia before bleeding, a hemoglobin level dropping below 7g within a short period indicates a large amount of blood loss, over 1200ml. Two to five hours after a massive hemorrhage, white blood cell count may increase, but it usually does not exceed 15×109/L. However, in cases of liver cirrhosis or hypersplenism, white blood cell count may not increase.

　　Five, Blood Urea Nitrogen

　　A few hours after upper gastrointestinal hemorrhage, blood urea nitrogen increases, reaching a peak in 1 to 2 days, and returning to normal within 3 to 4 days. If bleeding recurs, blood urea nitrogen can increase again. The increase in blood urea nitrogen is due to a large amount of blood entering the small intestine, with nitrogenous products being absorbed. A decrease in blood volume leads to a decrease in renal blood flow and glomerular filtration rate, causing not only an increase in blood urea nitrogen but also an increase in creatinine. If creatinine is below 133μmol/L (1.5mg%), while blood urea nitrogen is greater than 14.28mmol/L (40mg%), it indicates that upper gastrointestinal hemorrhage is above 1000ml.

　　Sixth, judgment of whether bleeding continues

　　Clinically, it cannot be solely judged whether bleeding continues based on the decrease in hemoglobin or the tarry stools. Because after one bleeding, the decrease in hemoglobin has a certain process, and after bleeding 1000ml, tarry stools can last for 1-3 days, and occult blood in stools can last for 1 week. After bleeding 2000ml, tarry stools can last for 4-5 days, and occult blood in stools can last for 2 weeks. The following symptoms should be considered as continued bleeding.

　　1. The frequency and amount of repeated vomiting of blood and black stools increase, or dark red to bright red blood stools are excreted.

　　2. The aspirate from the gastric tube contains a lot of fresh blood.

　　3. Within 24 hours, even with active fluid infusion and blood transfusion, blood pressure and pulse cannot be stabilized, and the general condition has not improved; or after rapid fluid infusion and blood transfusion, the central venous pressure is still decreasing.

　　4. Hemoglobin, red blood cell count, and hematocrit continue to decrease, and reticulocyte count continues to increase.

　　1. Treatment of the primary disease should be actively carried out under the guidance of a doctor, such as peptic ulcer and liver cirrhosis.

　　2. Live a regular life. Have regular and moderate meals, avoid overeating, and avoid alcohol, smoking, and strong tea and coffee.

　　3. Pay attention to the use of medication. Try to use as few or no irritating drugs to the stomach as possible. If necessary, add drugs to maintain the gastric mucosa.

　　4. Regular physical examinations should be conducted to detect early lesions and receive timely treatment. When symptoms of anemia such as dizziness appear, it is recommended to go to the hospital for a check-up as soon as possible.

　　5. Drinking milk regularly can prevent upper gastrointestinal bleeding. Upper gastrointestinal bleeding caused by peptic ulcer is often due to the erosion of the gastric wall by acidic gastric juice and the injury of blood vessels. To prevent excessive secretion of gastric acid during the peak period of gastric acid secretion at night, drinking a cup of warm milk before going to bed can protect the gastric mucosa and neutralize the gastric acid, and can effectively prevent recurrent bleeding. It is recommended to eat more fresh vegetables and fruits. Those with a tendency to bleed should eat more vitamin C and vitamin K-containing foods. The content of vitamin C in green vegetables is very rich, and the content of vitamin C in oranges, grapefruits, tomatoes, and lemons is also very high.

　　That is the prevention method for lower gastrointestinal bleeding. In fact, it is very simple and it is a habit that we should pay attention to in our daily life.

　　In recent years, there has been significant progress in the clinical research of gastrointestinal bleeding. In addition to continuing to use traditional methods such as barium meal or prolonged irrigation examination, endoscopic examination has been widely applied, and blood treatment has been developed on the basis of diagnosis.

　　(1) Barium X-ray examination: Suitable only for patients with stopped bleeding and stable condition, its positive rate for the diagnosis of the etiology of acute gastrointestinal bleeding is not high.

　　(2) Endoscopy.

　　(3) Angiography.

　　(4) Radionuclide imaging: In recent years, radionuclide imaging has been used to detect the location of active bleeding. The method is to inject 99mTc colloid intravenously and perform an abdominal scan to detect the evidence of tracer leakage from the blood vessels, which can serve as a preliminary directional indication.

　　Nutritional diet at different stages

　　1. Bleeding period

　　In cases of massive gastrointestinal bleeding, especially upper gastrointestinal bleeding, temporary fasting should be performed, and rapid intravenous fluid administration should be carried out. In cases of severe shock, blood transfusion should be prepared.

　　For mild bleeding, it is advisable to consume a liquid diet. If conditions permit, milk should be the main food in the short term. Milk can neutralize gastric acid and is conducive to hemostasis. In addition to milk, liquid diets can also include soy milk, rice porridge, lotus root powder, etc.

　　2. Recovery period

　　Generally, it is possible to start with small amounts of liquid diet 24 hours after the bleeding stops, and closely observe for any recurrence of bleeding. If the condition is stable, gradually increase the amount of liquid diet and consider changing to semi-liquid diet and soft food as appropriate, until normal diet is resumed. The liquid diet during the recovery period can refer to the liquid food selection table for upper gastrointestinal bleeding attached to the section on dietary prohibitions and taboos of this disease.

　　Dietary adjustment

　　Regularly drinking milk can prevent upper gastrointestinal bleeding. Upper gastrointestinal bleeding caused by peptic ulcer disease is often due to the erosion of the gastric wall by acidic gastric juice and the damage to blood vessels. To prevent excessive secretion of gastric acid during the peak period of gastric acid secretion at night, drinking a cup of warm milk before bedtime can protect the gastric mucosa and neutralize gastric acid, and can effectively prevent recurrent bleeding.

　　Eat more fresh vegetables and fruits. For those with a tendency to bleed, it is advisable to eat more foods rich in vitamin C and vitamin K. Green leafy vegetables are rich in vitamin C, and citrus fruits, grapefruits, tomatoes, and lemons also contain high levels of vitamin C. Spinach, cabbage, cauliflower, rapeseed, and vegetable oils contain higher levels of vitamin K. Eating more fresh fruits and vegetables rich in vitamin C and vitamin K can improve the permeability of capillaries, reduce the fragility of blood vessels, and be conducive to hemostasis. It is also advisable to eat more foods with hemostatic effects, such as peanut skin, white fungus, shepherd's purse, chrysanthemum, lily, lotus root juice, and cuttlefish bone.

　　Avoid food for gastrointestinal bleeding

　　1. Avoid alcohol, tobacco, strong tea, and coffee: Regular consumption of strong alcohol can greatly stimulate the gastric mucosa, and patients with upper gastrointestinal bleeding should abstain from drinking. Long-term alcoholism can also cause significant liver damage, affect the synthesis of coagulation factors, and easily trigger upper gastrointestinal bleeding.

　　The harmful components in tobacco leaves have a significant stimulating effect on the gastrointestinal mucosa, easily causing inflammation of the gastrointestinal mucosa, leading to dysfunction of the lower esophageal sphincter and pyloric sphincter, resulting in the reflux of bile and stomach contents, and exacerbating the condition. Smoking is particularly prohibited for patients with a history of upper gastrointestinal bleeding.

　　Strong tea and strong coffee can strongly stimulate the secretion of gastric acid, which is not conducive to the regression of gastrointestinal inflammation and the healing of ulcers, so patients with a history of gastrointestinal bleeding should not drink strong tea and coffee.

　　2. Avoid spicy and刺激性 food: Spicy, fragrant, fried food, etc., are hot and can ignite fire. In addition, seafood can be highly irritant and may damage the gastrointestinal mucosa, causing bleeding.

　　Rescue measures for massive gastrointestinal bleeding:

　　General treatment: bed rest, supine with head elevated, oxygen inhalation, monitoring blood pressure, pulse, limb temperature, blood loss, and urine output.

　　Maintain a patent venous route, monitor central venous pressure (normal 6-12cmH2O) for massive hemorrhage, and keep the respiratory tract patent for hematemesis. Hematemesis patients should be temporarily fasting. For mild to moderate bleeding, a small amount of fluid (such as congee) can be consumed 6-12 hours after hematemesis stops. For severe bleeding, a small amount of fluid diet can be consumed 24-48 hours after bleeding stops. For patients with altered consciousness, a gastric tube should be placed to understand the bleeding situation and avoid aspiration. Emergency tests include routine blood tests, blood typing, coagulation time, occult blood test in feces or vomit, electrolytes, and blood creatinine, urea nitrogen, etc.

　　Rapidly replenish blood volume: After massive hemorrhage, blood volume should be replenished first. When preparing for blood transfusion, normal saline, 5%-10% glucose solution, 706 plasma substitute, etc., should be infused intravenously immediately.

　　Precautions: ①Do not start blood transfusion alone without fluid infusion. It is recommended to start with fluid infusion, or both fluid infusion and blood transfusion in emergencies. ②When systolic blood pressure is below 50mmHg, the speed of fluid infusion and blood transfusion should be appropriately increased, and even pressure transfusion may be required to raise systolic blood pressure to 80-90mmHg as soon as possible. If the blood pressure can be stabilized, the speed of fluid infusion can be slowed down. ③When a large amount of stored blood is infused, 10ml of calcium gluconate should be administered intravenously every 600ml of blood. ④For patients with liver cirrhosis or acute gastric mucosal damage, fresh blood should be used as much as possible. ⑤The amount of blood transfusion should be 2/3 or 3/4 of the blood loss to avoid the risk of rebleeding due to increased portal pressure. ⑥For patients with heart, lung, kidney diseases, and elderly patients, it is necessary to prevent acute pulmonary edema caused by excessive and rapid fluid infusion and blood transfusion. Therefore, it is necessary to closely observe the general condition and vital signs of the patient, especially the filling condition of the jugular vein. At this time, the central venous pressure should be measured to monitor the infusion volume.

　　Indications for blood transfusion: ①Hb120 times/min; ④massive hematemesis or melena.

　　Indicators of sufficient blood volume: The extremities change from damp, cold, and cyanotic to warm and rosy; the pulse changes from rapid and weak to normal and strong; systolic blood pressure approaches normal, and the pulse pressure difference is >4kPa (30mmHg); urine output >30ml/h; central venous pressure returns to normal (5-13cmH2O).