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Overview of Gastrointestinal Bleeding


Parswa Ansari

, MD, Hofstra Northwell-Lenox Hill Hospital, New York

Last full review/revision Oct 2019| Content last modified Oct 2019
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Gastrointestinal (GI) bleeding can originate anywhere from the mouth to the anus and can be overt or occult. The manifestations depend on the location and rate of bleeding. (See also Varices and Vascular Gastrointestinal Lesions.)

Hematemesis is vomiting of red blood and indicates upper GI bleeding, usually from a peptic ulcer, vascular lesion, or varix. Coffee-ground emesis is vomiting of dark brown, granular material that resembles coffee grounds. It results from upper GI bleeding that has slowed or stopped, with conversion of red hemoglobin to brown hematin by gastric acid.

Hematochezia is the passage of gross blood from the rectum and usually indicates lower GI bleeding but may result from vigorous upper GI bleeding with rapid transit of blood through the intestines.

Melena is black, tarry stool and typically indicates upper GI bleeding, but bleeding from a source in the small bowel or right colon may also be the cause. About 100 to 200 mL of blood in the upper GI tract is required to cause melena, which may persist for several days after bleeding has ceased. Black stool that does not contain occult blood may result from ingestion of iron, bismuth, or various foods and should not be mistaken for melena.

Chronic occult bleeding can occur from anywhere in the GI tract and is detectable by chemical testing of a stool specimen.

Acute, severe bleeding also can occur from anywhere in the GI tract. Patients may present with signs of shock. Patients with underlying ischemic heart disease may develop angina or myocardial infarction because of coronary hypoperfusion.

GI bleeding in patients with underlying liver disease may precipitate portosystemic encephalopathy or hepatorenal syndrome (kidney failure secondary to liver failure).


There are many possible causes (see Table: Common Causes of Gastrointestinal (GI) Bleeding), which are divided into upper GI (above the ligament of Treitz), lower GI, and small bowel.

Bleeding of any cause is more likely, and potentially more severe, in patients with chronic liver disease (eg, alcoholic liver disease, chronic hepatitis), in those with hereditary coagulation disorders, or in those taking certain drugs. Drugs associated with GI bleeding include anticoagulants (eg, heparin, warfarin), those affecting platelet function (eg, aspirin and certain other nonsteroidal anti-inflammatory drugs [NSAIDs], clopidogrel, selective serotonin reuptake inhibitors [SSRIs]), and those affecting mucosal defenses (eg, NSAIDs).


Common Causes of Gastrointestinal (GI) Bleeding

Upper GI tract

Duodenal ulcer (20–30%)

Gastric or duodenal erosions (20–30%)

Varices (15–20%)

Gastric ulcer (10–20%)

Mallory-Weiss tear (5–10%)

Erosive esophagitis (5–10%)

Angioma (5–10%)


Lower GI tract (percentages vary with the age group sampled)

Angiodysplasia (vascular ectasia)

Colitis: Radiation, ischemic, infectious

Small-bowel lesions (rare)



Stabilization with airway management, IV fluids, or transfusions is essential before and during diagnostic evaluation.


History of present illness should attempt to ascertain quantity and frequency of blood passage. However, quantity can be difficult to assess because even small amounts (5 to 10 mL) of blood turn water in a toilet bowl an opaque red, and modest amounts of vomited blood appear huge to an anxious patient. However, most can distinguish between blood streaks, a few teaspoons, and clots.

Patients with hematemesis should be asked whether blood was passed with initial vomiting or only after an initial (or several) nonbloody emesis. In addition, the clinician should ask specific questions to distinguish between hematemesis and hemoptysis because patients may confuse the two symptoms.

Patients with rectal bleeding should be asked whether pure blood was passed; whether it was mixed with stool, pus, or mucus; or whether blood simply coated the stool or toilet paper. Those with bloody diarrhea should be asked about travel or other possible exposure to GI pathogens.

Review of symptoms should include presence of abdominal discomfort, weight loss, easy bleeding or bruising, previous colonoscopy or endoscopy results, and symptoms of anemia (eg, weakness, easy fatigability, dizziness).

Past medical history should inquire about previous GI bleeding (diagnosed or undiagnosed); known inflammatory bowel disease, bleeding diatheses, and liver disease; and use of any drugs that increase the likelihood of bleeding or chronic liver disease (eg, alcohol).

Physical examination

General examination focuses on vital signs and other indicators of shock or hypovolemia (eg, tachycardia, tachypnea, pallor, diaphoresis, oliguria, confusion) and anemia (eg, pallor, diaphoresis). Patients with lesser degrees of bleeding may simply have mild tachycardia (heart rate > 100).

Orthostatic changes in pulse (a change of > 10 beats/minute) or blood pressure (a drop of 10 mm Hg) often develop after acute loss of 2 units of blood. However, orthostatic measurements are unwise in patients with severe bleeding (possibly causing syncope) and generally lack sensitivity and specificity as a measure of intravascular volume, especially in elderly patients.

External stigmata of bleeding disorders (eg, petechiae, ecchymoses) are sought, as are signs of chronic liver disease (eg, spider angiomas, ascites, palmar erythema) and portal hypertension (eg, splenomegaly, dilated abdominal wall veins).

A digital rectal examination is necessary to search for stool color, masses, and fissures. Anoscopy is done to diagnose hemorrhoids. Chemical testing of a stool specimen for occult blood completes the examination if gross blood is not present.

Red flags

Several findings suggest hypovolemia or hemorrhagic shock:

  • Syncope

  • Hypotension

  • Pallor

  • Diaphoresis

  • Tachycardia

Interpretation of findings

The history and physical examination suggest a diagnosis in about 50% of patients, but findings are rarely diagnostic and confirmatory testing is required.

Epigastric abdominal discomfort relieved by food or antacids suggests peptic ulcer disease. However, many patients with bleeding ulcers have no history of pain. Weight loss and anorexia, with or without a change in stool, suggest a GI cancer. A history of cirrhosis or chronic hepatitis suggests esophageal varices. Dysphagia suggests esophageal cancer or stricture. Vomiting and retching before the onset of bleeding suggests a Mallory-Weiss tear of the esophagus, although about 50% of patients with Mallory-Weiss tears do not have this history.

A history of bleeding (eg, purpura, ecchymosis, hematuria) may indicate a bleeding diathesis (eg, hemophilia, hepatic failure). Bloody diarrhea, fever, and abdominal pain suggest ischemic colitis, inflammatory bowel disease (eg, ulcerative colitis, Crohn disease), or an infectious colitis (eg, Shigella, Salmonella, Campylobacter, amebiasis). Hematochezia suggests diverticulosis or angiodysplasia. Fresh blood only on toilet paper or the surface of formed stools suggests internal hemorrhoids or fissures, whereas blood mixed with the stool indicates a more proximal source. Occult blood in the stool may be the first sign of colon cancer or a polyp, particularly in patients > 45 years.

Blood in the nose or trickling down the pharynx suggests the nasopharynx as the source. Spider angiomas, hepatosplenomegaly, or ascites is consistent with chronic liver disease and hence possible esophageal varices. Arteriovenous malformations, especially of the mucous membranes, suggest hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome). Cutaneous nail bed and GI telangiectasia may indicate systemic sclerosis or mixed connective tissue disease.


Several tests are done to help confirm the suspected diagnosis.

  • Complete blood count (CBC), coagulation profile, and often other laboratory studies

  • Nasogastric tube (NGT) for all but those with minimal rectal bleeding

  • Upper endoscopy for suspected upper GI bleeding

  • Colonoscopy for lower GI bleeding (unless clearly caused by hemorrhoids)

CBC should be obtained in patients with large-volume or occult blood loss. Patients with more significant bleeding also require coagulation studies (eg, platelet count, prothrombin time [PT], partial thromboplastin time [PTT]) and liver tests (eg, bilirubin, alkaline phosphatase, albumin, aspartate aminotransferase [AST], alanine aminotransferase [ALT]). Type and cross-match are done if bleeding is ongoing. Hemoglobin and hematocrit may be repeated up to every 6 h in patients with severe bleeding. Additionally, one or more diagnostic procedures are typically required.

Nasogastric aspiration and lavage should be done in all patients with suspected upper GI bleeding (eg, hematemesis, coffee-ground emesis, melena, massive rectal bleeding). Bloody nasogastric aspirate indicates active upper GI bleeding, but about 10% of patients with upper GI bleeding have no blood in the nasogastric aspirate. Coffee-ground material indicates bleeding that is slow or stopped. If there is no sign of bleeding, and bile is returned, the NGT is removed; otherwise, it is left in place to monitor continuing or recurrent bleeding. Nonbloody, nonbilious return is considered a nondiagnostic aspirate.

Upper endoscopy (examination of the esophagus, stomach, and duodenum) should be done for upper GI bleeding. Because endoscopy may be therapeutic as well as diagnostic, it should be done rapidly for significant bleeding but may be deferred for 24 hours if bleeding stops or is minimal. Upper GI barium x-rays have no role in acute bleeding, and the contrast used may obscure subsequent attempts at angiography. Angiography is useful in the diagnosis of upper GI bleeding and permits certain therapeutic maneuvers (eg, embolization, vasoconstrictor infusion).

Flexible sigmoidoscopy and anoscopy may be all that is required acutely for patients with symptoms typical of hemorrhoidal bleeding. All other patients with hematochezia should have colonoscopy, which can be done electively after routine preparation unless there is significant ongoing bleeding. In such patients, a rapid prep (5 to 6 L of polyethylene glycol solution delivered via NGT or by mouth over 3 to 4 hours) often allows adequate visualization. If colonoscopy cannot visualize the source and ongoing bleeding is sufficiently rapid (> 0.5 to 1 mL/minute), angiography may localize the source. Some angiographers first take a radionuclide scan to focus the examination, because angiography is less sensitive than the radionuclide scan. The American College of Gastroenterology’s 2016 guidelines on management of patients with acute lower GI bleeding suggest doing CT angiography to localize the bleeding site before angiography or surgery.

Diagnosis of occult bleeding can be difficult, because heme-positive stools may result from bleeding anywhere in the GI tract. Endoscopy is the preferred method, with symptoms determining whether the upper or lower GI tract is examined first. Double-contrast barium enema and sigmoidoscopy can be used for the lower tract when colonoscopy is unavailable or the patient refuses it.

If the results of upper endoscopy and colonoscopy are negative and occult blood persists in the stool, an upper GI series with small-bowel follow-through, CT enterography, small-bowel endoscopy (enteroscopy), capsule endoscopy (which uses a small pill-like camera that is swallowed), technetium-labeled colloid or red blood cell (RBC) scan, and angiography should be considered. Capsule endoscopy is of limited value in an actively bleeding patient.


  • Secure airway if needed

  • IV fluid resuscitation

  • Blood transfusion if needed

  • Sometimes drugs

  • In some, endoscopic or angiographic hemostasis

(See also the American College of Gastroenterology’s [ACG] practice guidelines on management of patients with acute lower GI bleeding, the practice guidelines on management of patients with ulcer bleeding, and the practice guidelines on diagnosis and management of small bowel bleeding.)

Hematemesis, hematochezia, or melena should be considered an emergency. Admission to an intensive care unit, with consultation by both a gastroenterologist and a surgeon, is recommended for all patients with severe GI bleeding. General treatment is directed at maintenance of the airway and restoration of circulating volume. Hemostasis and other treatment depend on the cause of the bleeding.


A major cause of morbidity and mortality in patients with active upper GI bleeding is aspiration of blood with subsequent respiratory compromise. To prevent these problems, endotracheal intubation should be considered in patients who have inadequate gag reflexes or are obtunded or unconscious—particularly if they will be undergoing upper endoscopy.

Fluid resuscitation and blood product transfusion

Intravenous access should be obtained immediately. Short, large-bore (eg, 14- to 16-gauge) IV catheters in the antecubital veins are preferable to a central venous catheter unless a large (8.5 Fr) sheath is used. IV fluids are initiated immediately, as for any patient with hypovolemia or hemorrhagic shock (see Intravenous Fluid Resuscitation). Healthy adults are given normal saline IV in 500- to 1000-mL aliquots until signs of hypovolemia remit—up to a maximum of 2 L (for children, 20 mL/kg, that may be repeated once).

Patients requiring further resuscitation should receive transfusion with packed RBCs. Transfusions continue until intravascular volume is restored and then are given as needed to replace ongoing blood loss. Transfusions in older patients or those with coronary artery disease may be stopped when hematocrit is stable at 30 unless the patient is symptomatic. Younger patients or those with chronic bleeding are usually not transfused unless hematocrit is < 23 or they have symptoms such as dyspnea or coronary ischemia.

Platelet count should be monitored closely; platelet transfusion may be required with severe bleeding. Patients who are taking antiplatelet drugs (eg, clopidogrel, aspirin) have platelet dysfunction, often resulting in increased bleeding. Platelet transfusion should be considered when patients taking these drugs have severe ongoing bleeding, although a residual circulating drug (particularly clopidogrel) may inactivate transfused platelets. If patients are taking an antiplatelet drug or an anticoagulant for a recent cardiovascular indication, a cardiologist should be consulted, if possible, prior to stopping the drug, reversing the drug, or giving a platelet transfusion.

If a significant blood transfusion is required, fresh frozen plasma and platelets also should be transfused along with packed RBCs according to the institution's massive transfusion protocols. If the patient has a coagulopathy, correction with fresh frozen plasma or prothrombin complex concentrate should be considered.


An IV proton pump inhibitor (PPI) should be started in cases of possible upper GI bleeding.

Octreotide (a synthetic analog of somatostatin) is used in patients with suspected variceal bleeding. Octreotide is given as a 50-mcg IV bolus, followed by continuous infusion of 50 mcg/hour.


GI bleeding stops spontaneously in about 80% of patients. The remaining patients require some type of intervention. Specific therapy depends on the bleeding site. Early intervention to control bleeding is important to minimize mortality, particularly in elderly patients.

For peptic ulcer, ongoing bleeding or rebleeding is treated with endoscopic coagulation (with bipolar electrocoagulation, injection sclerotherapy, heater probes, clips, or laser; 1). Nonbleeding vessels that are visible within an ulcer crater are also treated. If endoscopy does not stop the bleeding, angiographic embolization of the bleeding vessel may be attempted, or surgery is required to oversew the bleeding site. If the patient has been treated medically for peptic ulcer disease but has recurrent bleeding, surgeons do acid-reduction surgery at the same time.

Active variceal bleeding can be treated with endoscopic banding, injection sclerotherapy, or a transjugular intrahepatic portosystemic shunting (TIPS) procedure (1).

Severe, ongoing lower GI bleeding caused by diverticula or angiomas can sometimes be controlled colonoscopically by clips, electrocautery, coagulation with a heater probe, or injection with dilute epinephrine (see ACG practice guidelines on management of patients with acute lower GI bleeding). Polyps can be removed by snare or cautery. If these methods are ineffective or unfeasible, angiography with embolization or vasopressin infusion may be successful. However, because collateral blood flow to the bowel is limited, angiographic techniques have a significant risk of bowel ischemia or infarction unless super-selective catheterization techniques are used. In most series, the rate of ischemic complications is < 5%. Vasopressin infusion has about an 80% success rate for stopping bleeding, but bleeding recurs in about 50% of patients. Also, there is a risk of hypertension and coronary ischemia. Furthermore, angiography can be used to localize the source of bleeding more accurately.

Surgery may be done in patients with continued lower GI bleeding (requiring > 6 units transfusion), but localization of the bleeding site is very important. If the bleeding site cannot be localized, subtotal colectomy is recommended. Blind hemicolectomy (with no preoperative identification of the bleeding site) carries a much higher mortality risk than does directed segmental resection and may not remove the bleeding site; the rebleeding rate is 40%. However, assessment must be expeditious so that surgery is not unnecessarily delayed. In patients who have received > 10 units of packed RBCs, the mortality rate is about 30%.

Acute or chronic bleeding of internal hemorrhoids stops spontaneously in most cases. Patients with refractory bleeding are treated via anoscopy with rubber band ligation, injection, coagulation, or surgery.

Treatment reference

Geriatrics Essentials

In the elderly, hemorrhoids and colorectal cancer are the most common causes of minor bleeding. Peptic ulcer, diverticular disease, and angiodysplasia are the most common causes of major bleeding. Variceal bleeding is less common than in younger patients.

Massive GI bleeding is tolerated poorly by elderly patients. Diagnosis must be made quickly, and treatment must be started sooner than in younger patients, who can better tolerate repeated episodes of bleeding.

Key Points

  • Rectal bleeding may result from upper or lower GI bleeding.

  • Orthostatic changes in vital signs are unreliable markers for serious bleeding.

  • Hematemesis, hematochezia, or melena should be considered an emergency and managed in an intensive care unit.

  • IV fluid resuscitation should begin immediately and may require transfusion with blood products.

  • About 80% of patients stop bleeding spontaneously; various endoscopic techniques are usually the first choice for the remainder.

More Information

  • The American College of Gastroenterology’s practice guidelines on management of patients with acute lower GI bleeding

  • The American College of Gastroenterology’s practice guidelines on management of patients with ulcer bleeding

  • The American College of Gastroenterology's practice guidelines on diagnosis and management of small bowel bleeding

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