Gastrointestinal bleeding refers to bleeding occurring anywhere along the gastrointestinal tract, from the esophagus to the anus. Based on the site of bleeding, it can be classified into upper gastrointestinal bleeding, small intestine bleeding, and lower gastrointestinal bleeding, with upper gastrointestinal bleeding being the most common. Clinical manifestations include hematemesis, melena, or hematochezia. Mild cases may present without symptoms, while severe cases may involve anemia, hypovolemia, or even shock, which can be life-threatening.
Sites and Etiology
Upper Gastrointestinal Bleeding (UGIB)
Upper gastrointestinal bleeding is a common medical emergency and refers to bleeding originating from the gastrointestinal tract proximal to the ligament of Treitz, including the esophagus, stomach, duodenum, bile ducts, and pancreatic ducts. The causes can be divided into non-variceal bleeding and variceal bleeding. The most common causes include peptic ulcers, upper gastrointestinal tumors, stress ulcers, and acute or chronic inflammation of the upper gastrointestinal mucosa. Other causes include:
- Esophageal diseases: Mallory-Weiss tears, esophageal injuries caused by instrumentation, foreign bodies, or radiation; chemical injuries from strong acids or alkalis; esophageal diverticulitis; and aortic aneurysm rupture into the esophagus.
- Gastric and duodenal diseases: Polyps, rupture of submucosal arteries (Dieulafoy's disease), gastrointestinal stromal tumors, hemangiomas, injuries from foreign bodies or radiation, anastomotic ulcers, duodenal diverticula, and gastrinomas.
- Variceal bleeding: Ruptured esophageal or gastric varices, portal hypertensive gastropathy, and ruptured ectopic duodenal varices.
- Biliary tract bleeding: Causes include gallstones, biliary ascariasis, gallbladder or bile duct cancer, post-surgical biliary injuries, and rupture of liver cancers or hepatic hemangiomas into the bile ducts.
- Pancreatic diseases involving the duodenum: Causes include pancreatic cancer or abscess rupture associated with acute pancreatitis.
Small Intestine Bleeding
Small intestine bleeding refers to bleeding occurring between the ligament of Treitz and the ileocecal valve. It can result from primary gastrointestinal diseases or systemic conditions, as well as from the use of certain medications. Age is an important factor, as the causes of bleeding vary across age groups:
- Young patients (16–40 years): Common causes include Crohn's disease, small intestinal adenomas, Meckel's diverticulum, Dieulafoy's disease, vascular lesions, celiac disease, and nonspecific enteritis (e.g., immune-mediated or infectious).
- Middle-aged patients (41–65 years): Common causes include vascular lesions, small intestinal tumors, nonspecific enteritis, intestinal ulcers, and drug-related bleeding.
- Elderly patients (>65 years): Common causes include vascular lesions, NSAID-related ulcers, small intestinal tumors, nonspecific inflammation and ulcers, and celiac disease.
- Rare causes: These include ruptured ectopic varices, aortoenteric fistulas, endometriosis, metastatic cancers, and foreign bodies.
Lower Gastrointestinal Bleeding (LGIB)
Lower gastrointestinal bleeding refers to bleeding originating from the gastrointestinal tract distal to the ileocecal valve, including the colon, rectum, and anal canal. Common causes include hemorrhoids, anal fissures, intestinal polyps, colorectal cancer, diverticular disease, varices, inflammatory conditions (e.g., ulcerative colitis, ischemic colitis, infectious colitis), radiation colitis, neuroendocrine tumors, vascular lesions, and intussusception.
Systemic Diseases
Systemic diseases may nonspecifically involve parts of the gastrointestinal tract or cause diffuse bleeding throughout the entire gastrointestinal tract.
- Vascular diseases: Examples include Henoch-Schönlein purpura, atherosclerosis, polyarteritis nodosa, systemic lupus erythematosus, hereditary hemorrhagic telangiectasia, pseudoxanthoma elasticum, and malignant atrophic papulosis (Degos disease).
- Hematological diseases: Examples include hemophilia, immune thrombocytopenic purpura, leukemia, disseminated intravascular coagulation (DIC), and other coagulation disorders.
- Other conditions: Examples include uremia, hemorrhagic fever, or leptospirosis.
Obscure Gastrointestinal Bleeding (OGIB)
Obscure gastrointestinal bleeding refers to persistent or recurrent gastrointestinal bleeding with no identifiable cause after upper endoscopy, colonoscopy, capsule endoscopy, enteroscopy, and imaging studies. It can involve any part of the gastrointestinal tract.
Clinical Manifestations
The clinical manifestations of gastrointestinal bleeding depend on the volume, speed, location, and nature of the bleeding, as well as the patient’s age and the compensatory ability of their circulatory system.
Hematemesis
Hematemesis is a characteristic manifestation of upper gastrointestinal bleeding (UGIB). Large-volume bleeding often presents with hematemesis, while smaller volumes may not. Slow bleeding typically results in vomitus that is brown or coffee-ground in appearance, whereas rapid, large-volume bleeding produces bright red blood or blood clots, as the blood does not mix sufficiently with gastric acid.
Melena
Melena presents as tarry, sticky, and shiny black stools. It is commonly seen in UGIB, bleeding from the upper small intestine, or even bleeding from the right colon. Prolonged retention of blood in the intestinal lumen can also result in melena.
Hematochezia
Hematochezia is more commonly associated with bleeding from the small intestine or lower gastrointestinal tract. However, UGIB with bleeding volumes exceeding 1,000 mL may also present with hematochezia, which appears as dark red or even fresh red stool.
Hypovolemic Peripheral Circulatory Failure
Acute massive bleeding leads to a rapid reduction in circulating blood volume, resulting in peripheral circulatory failure. Symptoms include dizziness, palpitations, fatigue, fainting upon sudden standing, cold extremities, tachycardia, and hypotension. Severe cases may progress to shock.
Anemia and Hematological Changes
Acute massive bleeding results in hemorrhagic anemia. However, during the early stages of bleeding, hemoglobin concentration, red blood cell count, and hematocrit may not show significant changes. After bleeding, tissue fluid enters the blood vessels, diluting the blood, and anemia typically becomes apparent in 3–4 hours or longer. Maximum blood dilution occurs 24–72 hours after bleeding. The severity of anemia depends on the volume of blood loss, the presence of pre-existing anemia, and the balance of body fluids after bleeding. Reticulocyte count increases within 24 hours after bleeding and gradually normalizes after bleeding stops. Chronic blood loss can manifest as iron-deficiency anemia.
Acute bleeding often results in normocytic normochromic anemia.
Chronic blood loss typically presents as microcytic hypochromic anemia.
Compensatory bone marrow hyperplasia following acute bleeding may temporarily cause macrocytic anemia.
Fever and Azotemia
Some patients develop low-grade fever within 24 hours after massive gastrointestinal bleeding, which may persist for several days to a week before returning to normal. Blood urea nitrogen levels begin to rise within a few hours after bleeding, peaking at 24–48 hours, often not exceeding 14.3 mmol/L (40 mg/dL). Blood urea nitrogen levels generally normalize 3–4 days after bleeding stops.
Diagnosis
Confirmation of Gastrointestinal Bleeding
Gastrointestinal bleeding can be diagnosed based on clinical manifestations such as hematemesis, melena, hematochezia, and hypovolemic peripheral circulatory failure. Strongly positive occult blood tests on vomitus or black stools, along with laboratory evidence of decreased hemoglobin concentration, red blood cell count, and hematocrit, support the diagnosis. However, other sources of bleeding must be excluded, such as:
- Differentiation between hematemesis and hemoptysis.
- Bleeding from the mouth, nose, or throat.
- Black stools caused by food or medications, such as animal blood, charcoal, iron supplements, or bismuth preparations.
Assessment of Bleeding Severity and Circulatory Status
The severity of the condition correlates with the volume of blood loss:
- Daily blood loss exceeding 5 mL results in a positive fecal occult blood test.
- Daily blood loss exceeding 50 mL may cause melena.
- Gastric blood accumulation exceeding 250 mL can lead to hematemesis.
Blood loss of less than 400 mL is usually compensated by tissue fluids and splenic blood reserves, often without systemic symptoms. Blood loss exceeding 400 mL may cause symptoms such as dizziness, palpitations, and fatigue. Blood loss exceeding 1,000 mL within a short time can result in shock.
When gastrointestinal bleeding has not been definitively ruled out, the severity of bleeding can be inferred by observing circulatory status. Early signs of insufficient circulating blood volume include orthostatic hypotension, defined as a drop in blood pressure exceeding 15–20 mmHg or an increase in heart rate exceeding 10 beats per minute when transitioning from a supine to a seated position. Severe bleeding is indicated by systolic blood pressure below 90 mmHg, heart rate exceeding 120 beats per minute, pale complexion, cold and clammy extremities, restlessness, or confusion, suggesting massive bleeding and shock.
Determination of Ongoing Bleeding
Since it takes approximately three days to clear accumulated blood from the gastrointestinal tract, the presence of melena does not necessarily indicate ongoing bleeding. The following signs suggest active gastrointestinal bleeding:
- Recurrent hematemesis or increased frequency of melena/hematochezia, accompanied by hyperactive bowel sounds.
- Persistent or worsening circulatory instability despite adequate fluid resuscitation and blood transfusion.
- Continued decline in hemoglobin concentration, red blood cell count, and hematocrit.
- Persistent or recurrent elevation of blood urea nitrogen despite adequate fluid replacement and urine output.
- The presence of fresh blood in gastric aspirates obtained via nasogastric tube.
Determination of Bleeding Location and Cause
Medical History and Physical Examination
A thorough physical examination should include assessment of vital signs, mental status, and systemic examinations such as cardiovascular, pulmonary, and abdominal evaluations. A digital rectal examination should also be performed.
Gastroscopy and Colonoscopy
Gastroscopy and colonoscopy are the first-line methods for diagnosing the cause, location, and severity of upper gastrointestinal bleeding (UGIB) and lower gastrointestinal bleeding (LGIB). These procedures allow for timely and precise hemostatic treatment of the bleeding site. Emergency gastroscopy and colonoscopy are typically performed within 12–24 hours after hemodynamic stabilization. This timing is crucial because lesions such as acute erosive hemorrhagic gastritis may heal within a few days without leaving visible traces, and vascular abnormalities are often easier to detect during active or recent bleeding. Before endoscopic examinations, shock should be corrected, blood volume replenished, anemia improved, and hemostatic medications administered. Once the patient’s circulatory status is relatively stable, endoscopic examination can be performed promptly, and endoscopic hemostatic treatment can be applied based on the characteristics of the lesion.
Capsule Endoscopy and Enteroscopy
Capsule endoscopy is a first-line diagnostic tool for small intestinal bleeding, with strong detection capabilities for superficial mucosal lesions and small-to-medium vascular abnormalities. The diagnostic yield for small intestinal bleeding ranges from 38% to 83%. For lesions identified through capsule endoscopy, double-balloon or push enteroscopy can be used to access the small intestine via the oral or anal route for biopsy or therapeutic intervention.
Imaging Studies
X-ray barium studies
These can help detect diverticula and larger tumors with raised or depressed morphology in the intestine. However, barium studies are not recommended during acute gastrointestinal bleeding due to their low sensitivity and the potential to interfere with subsequent endoscopic, angiographic, or surgical treatments.
Abdominal CT
This is valuable for diagnosing patients with abdominal masses or signs of intestinal obstruction.
CT enterography (CTE)
For patients with suspected small intestinal strictures, such as those with a history of surgery, radiation therapy, or suspected Crohn’s disease, CTE can be used as an alternative to capsule endoscopy.
Selective angiography
This is indicated when endoscopy fails to identify the bleeding site and arterial bleeding is suspected. The extravasation of contrast medium is the most reliable sign of gastrointestinal bleeding, and transcatheter embolization can be performed immediately for hemostasis.
Radionuclide-labeled red blood cell scanning
This technique is advantageous for detecting intermittent bleeding over the half-life of the radionuclide, allowing continuous monitoring.
Ultrasound, CT, and MRI
These are helpful in evaluating hepatobiliary and pancreatic diseases and are commonly used for diagnosing biliary tract bleeding.
Surgical Exploration
Surgical exploration is necessary when the bleeding site cannot be identified through other diagnostic methods and ongoing massive bleeding poses a life-threatening risk. However, small lesions, particularly vascular abnormalities, may still be difficult to detect during surgery. In such cases, intraoperative endoscopy can assist in locating the bleeding site.
Prognostic Assessment
Early identification of patients at high risk for rebleeding or death and the implementation of enhanced monitoring and aggressive treatment are key to managing acute massive gastrointestinal bleeding. The following factors are associated with higher mortality rates:
- Advanced age (>65 years).
- Presence of severe comorbidities, such as cardiac, pulmonary, hepatic, or renal dysfunction, or cerebrovascular events.
- Large-volume bleeding or recurrent bleeding within a short period.
- Esophageal or gastric variceal bleeding accompanied by liver failure.
- Exposure of large blood vessels at the base of a peptic ulcer.
Treatment
Massive gastrointestinal bleeding is a critical condition with rapid progression. The primary goal of treatment is to counteract shock and rapidly replenish blood volume.
General Emergency Measures
Patients should remain in a supine position. The airway should be kept clear to prevent aspiration during hematemesis. Oxygen supplementation may be necessary. Oral intake should be avoided during active bleeding.
Vital signs, including heart rate, blood pressure, respiratory rate, urine output, and mental status, should be closely monitored. The frequency and characteristics of hematemesis, melena, and hematochezia should be observed. Regular monitoring of hemoglobin concentration, red blood cell count, hematocrit, and blood urea nitrogen levels is necessary. Central venous pressure (CVP) may be measured when indicated. Elderly or critically ill patients may require continuous electrocardiographic monitoring.
Aggressive Blood Volume Replenishment
Rapid establishment of effective intravenous access and blood volume replenishment is essential. Central venous catheterization may be necessary in some cases. Blood typing and cross-matching should be performed immediately. While awaiting cross-matched blood, balanced solutions, glucose-saline solutions, or colloid volume expanders may be administered.
The infusion rate should aim to maintain adequate tissue perfusion, with urine output serving as a valuable indicator. Care should be taken to avoid fluid overload, which may lead to pulmonary edema, especially in elderly patients or those with pre-existing cardiac conditions. CVP measurements can guide fluid administration in such cases.
The following signs indicate adequate blood volume replenishment:
- Restoration of consciousness.
- Warm and pink extremities, with reduced cyanosis and moisture. A reduction in the temperature difference between rectal and skin temperatures (<1°C).
- Normalization of pulse and blood pressure.
- Urine output >0.5 mL/(kg·h).
- Improvement in CVP.
Indications for transfusion of packed red blood cells include:
- Systolic blood pressure <90 mmHg or a drop >30 mmHg from baseline.
- Tachycardia (>120 beats/min).
- Hemoglobin <70 g/L.
For patients with cardiovascular disease, it is recommended to adopt a higher transfusion threshold.
Hemostatic Measures
Hemostatic treatment should be conducted based on the underlying disease and the location of the gastrointestinal lesion.
Upper Gastrointestinal Bleeding (UGIB)
UGIB can be classified as either variceal or non-variceal bleeding. This section focuses on the management of non-variceal bleeding. In general, aspirin and other NSAIDs should be discontinued during the acute phase of peptic ulcer bleeding. For patients with coronary artery disease requiring antiplatelet therapy, a multidisciplinary consultation is recommended. If the risk of cardiovascular complications outweighs the risk of gastrointestinal bleeding, antiplatelet therapy should be resumed as soon as possible, in combination with acid-suppressive therapy.
Acid Suppression Therapy
Hemostasis induced by platelet aggregation and plasma coagulation functions is effective only when the gastric pH is greater than 6.0. Additionally, newly formed blood clots are rapidly digested in gastric juice with a pH below 5.0. Therefore, suppressing gastric acid secretion and increasing intragastric pH have hemostatic effects. Proton pump inhibitors (PPIs) are commonly used and should be administered intravenously at an early stage. Intravenous PPI administration before endoscopy can improve the appearance of bleeding lesions during the procedure. For patients at high risk of rebleeding after endoscopic treatment, continued intravenous PPI therapy is recommended to reduce the risk of rebleeding. Once bleeding has stopped, oral PPI therapy should be initiated, with dosage and duration determined by the specific bleeding condition.
Endoscopic Therapy
Approximately 80% of peptic ulcer bleeding cases resolve spontaneously without specific intervention, but some patients may experience persistent bleeding or rebleeding. Patients with low rebleeding risk can be treated on an outpatient basis, while high-risk patients (e.g., those with active arterial bleeding, exposed blood vessels, or adherent clots observed during endoscopy) require aggressive endoscopic treatment and hospitalization. Endoscopic hemostatic techniques include injection therapy, thermal coagulation, and mechanical methods.
- Injection therapy: Options include 1:10,000 epinephrine saline solution or hypertonic saline-epinephrine solution, which are simple and easy to use.
- Thermal coagulation: Methods such as high-frequency electrocautery, argon plasma coagulation, thermal probes, and microwave coagulation provide reliable hemostasis but require specific equipment and technical expertise.
- Mechanical methods: Hemostatic clips are particularly effective for active bleeding but may be challenging to use in certain anatomical locations. Clinical evidence suggests that combining local injection therapy with either thermal or mechanical methods improves the effectiveness of hemostasis at the bleeding site.
Interventional Therapy
When endoscopic treatment is unsuccessful, vascular embolization of the gastroduodenal artery can be performed. Due to the rich collateral circulation among the arteries supplying the upper gastrointestinal tract, the risk of tissue necrosis after embolization is relatively low.
Surgical Treatment
Surgery becomes necessary when pharmacological, endoscopic, and interventional treatments fail to control bleeding and ongoing bleeding poses a life-threatening risk.
Small Intestinal Bleeding
For small intestinal ulcers and erosions caused by NSAIDs, discontinuation and avoidance of these drugs are essential. Bleeding caused by submucosal vein abnormalities or mucosal capillary malformations often resolves spontaneously, but the rebleeding rate can reach 50%.
Vasoconstrictive Agents
Somatostatin or somatostatin analogs are commonly used to induce hemostasis by constricting visceral blood vessels.
Glucocorticoids and Biologics
These are used to rapidly control underlying diseases, such as autoimmune conditions (e.g., Crohn's disease or intestinal Behçet's disease), that cause bleeding.
Endoscopic Therapy
If bleeding lesions are identified during endoscopy, hemostasis can be achieved through endoscopic techniques such as high-frequency electrocautery, argon plasma coagulation, or the use of hemostatic clips to coagulate or occlude the residual ends of small submucosal vessels. These methods are suitable for patients with localized lesions. Small intestinal polyps can also be resected endoscopically.
Vascular Interventions
For arterial bleeding caused by various conditions, mesenteric angiography and embolization can be performed when pharmacological and endoscopic treatments fail. Since embolization for small intestinal bleeding carries a risk of intestinal ischemia, which can lead to intestinal necrosis in severe cases, superselective catheterization of the responsible artery using microcatheters is required. Coils are commonly used for embolization. For diffuse bleeding or cases without obvious abnormalities on angiography, intra-arterial infusion of hemostatic agents can reduce arterial blood flow and achieve hemostasis.
Surgical Indication
Surgery is indicated in the following scenarios:
- Meckel's diverticulum.
- Tumors.
- Persistent bleeding that is life-threatening despite medical, endoscopic, and interventional treatments, regardless of whether the bleeding lesion has been definitively diagnosed.
In cases where the bleeding cause is uncertain, intraoperative endoscopy is an essential adjunct to locate the bleeding site.
Lower Gastrointestinal Bleeding (LGIB)
Hemorrhoids
Treatment options include rectal suppositories, sclerotherapy, and ligation.
Polyps
Endoscopic resection is the treatment of choice.
Ulcerative Colitis
This refer to the relevant sections for detailed management.
Vascular Lesions
Endoscopic hemostasis is the primary approach. If hemostasis is inadequate, vascular embolization may be performed.
IgA Vasculitis
Glucocorticoid therapy is commonly used.
Various Tumors
Surgical or endoscopic resection is indicated.
Persistent Bleeding
When bleeding persists despite pharmacological, endoscopic, and interventional treatments and poses a life-threatening risk, surgery is indicated regardless of whether the bleeding lesion has been definitively diagnosed.