AUTHOR AND EDITOR INFORMATION

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• Clinical
• Differentials
• Workup
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• Medication
• Follow-up
• Miscellaneous
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INTRODUCTION

Section 2 of 11  

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• Follow-up
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Background

Lower gastrointestinal bleeding (LGIB) accounts for 20-33% of episodes of gastrointestinal hemorrhage. Although LGIB is statistically less common than upper gastrointestinal bleeding (UGIB), it has been suggested that LGIB is underreported because a higher percentage of patients with LGIB do not seek medical attention.¹ LGIB is distinct from UGIB in epidemiology, management, and prognosis.

LGIB encompasses a wide spectrum of symptoms, ranging from trivial hematochezia to massive hemorrhage with shock. Acute LGIB is defined as bleeding that is of recent duration, that originates beyond the ligament of Treitz, that results in instability of vital signs, and that is associated with signs of anemia with or without need for blood transfusion.

LGIB has a mortality rate ranging from 10-20%, with patients of advanced age and patients with comorbid conditions at greatest risk. LGIB is more likely in the elderly because of a higher incidence of diverticulosis and vascular disease in these groups. The incidence of LGIB is higher in men than in women.

Pathophysiology

See Causes.

Frequency

United States

LGIB that requires hospitalization represents less than 1% of all hospital admissions in the United States. The leading causes of significant LGIB are diverticulosis and angiodysplasia. Diverticulosis accounts for 30-50% of the cases of hemodynamically significant LGIB, while angiodysplasia accounts for 20-30% of cases.² Some experts believe that angiodysplasia is the most frequent cause of LGIB in patients older than 65 years. Hemorrhoids are the most common cause of LGIB in patients younger than 50 years, but bleeding is usually minor and is rarely the cause of significant LGIB. According to a review of 7 series of patients with LGIB, the most common cause of LGIB was diverticulosis, accounting for 33% of cases, followed by cancer and polyps, which accounted for 19% of cases.³

Mortality/Morbidity

LGIB symptoms range from trivial hematochezia to massive hemorrhage with shock. The mortality rate ranges from 10-20%. Patients of advanced age and patients with comorbid conditions are at greatest risk.

Sex

LGIB is somewhat more common in men than in women because diverticulosis and vascular disease are more common in men.

Age

LGIB is more common in the elderly than in younger people because diverticulosis and vascular disease are more common in these groups.

See related CME at Gastrointestinal Bleeding in the Elderly.

CLINICAL

Section 3 of 11  

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History

The evaluation of lower gastrointestinal bleeding (LGIB) should begin with a thorough history and physical examination to provide valuable clues into the etiology and anatomical source of bleeding. For example, an elderly patient with atherosclerotic heart disease who presents with intermittent LGIB and syncope may well have angiodysplastic lesions as the cause of bleeding.

A history should determine whether this is a first or recurrent episode; whether a history of nonsteroidal anti-inflammatory drug (NSAID) or aspirin use exists; and whether the presence of systemic diseases, such as HIV, inflammatory bowel disease, and polyarteritis nodosa, exist. In patients with cancer, the history of radiation, chemotherapy, or both should be considered. Patients should be asked for history of coagulopathies, which may precipitate or exacerbate an episode of LGIB. The manner of presentation could also provide clues. Patients presenting with fever, abdominal cramps, and LGIB after consumption of contaminated food are likely to have an infectious etiology.

The clinical presentation of LGIB varies with the anatomical source of the bleeding as well as with the etiology. Commonly, LGIB from the right side of the colon can manifest as maroon stools, whereas a left-sided bleeding source may be evidenced by bright red blood per rectum. In practice, however, patients with UGIB and right-sided colonic bleeding may also present with bright red blood per rectum if the bleeding is brisk and massive. Similarly, cecal bleeding may present with melena, which is typically seen with UGIB, suggesting no distinct method exists for determining the anatomical source of bleeding based solely on stool color.

Depending on the etiology, the presentation of LGIB can vary. A young patient may present with fever, dehydration, abdominal cramps, and hematochezia caused by infectious or noninfectious (idiopathic) colitis. An older patient may present with painless bleeding and minimal symptoms caused by diverticular bleeding or angiodysplasia. LGIB can be mild and intermittent, as often is the case of angiodysplasia, or moderate or severe, as may be the situation diverticula-related bleeding.

Although diverticular bleeding is painless, patients may experience mild abdominal cramping due to the intraluminal blood that triggers spasmodic contraction of the colonic wall. Bleeding is usually acute, without antecedent symptoms, and in 70-80% of cases, is self-limited. Rebleeding can occur in up to 25% of patients.⁴ If the bleeding is brisk and voluminous, patients may be hypotensive and display signs of shock. Chronic, intermittent, minimal blood loss per rectum is unlikely to be caused by diverticular bleeding because diverticular bleeding is arterial in origin.

Significant angiodysplasia-related bleeding, like diverticular bleeding, presents as painless, self-limited hematochezia or melena; angiodysplasia-related bleeding is venocapillary. Patients may present with hemoccult-positive stools, iron-deficiency anemia, and syncope from chronic, intermittent bleeding. Occasionally, patients can present with bleeding of large quantities. The angiographic finding consists of clusters of small arteries during the arterial phase, accumulation of contrast media in the vascular tufts, and persistent opacification due to the late emptying of the draining veins.

Ischemic colitis may or may not present with abdominal pain and associated bloody diarrhea. The bloody diarrhea is self-limited but can recur if the underlying cause is not corrected. Although the clinical presentation is indistinguishable at times from that of infectious colitis, idiopathic colitis, and radiation–induced colitis, patients are usually older with cardiovascular comorbidities. Ischemic colitis may be fulminant, presenting with acute abdominal pain, rectal bleeding, and hypotension; or ischemic colitis may be insidious, presenting with pain and rectal bleeding over several weeks.

The bleeding associated with colon cancer, particularly right-sided bleeding, can be insidious, with patients presenting with iron-deficiency anemia and syncope. Right-sided colon cancer may also present with maroon-colored stools or melena, whereas left-sided colonic cancers can present as bright red blood per rectum, which can sometimes be confused with hemorrhoidal bleeding.

In infectious colitis, the clinical presentation of fever, diarrhea, dehydration, and abdominal pain can be caused by any of a number of bacterial, viral, or parasitic pathogens. Specific etiology can only be determined by isolating the organism from the stool, blood, or other tissue fluid. Clinical examination findings vary depending on the volume status, amount of blood loss, extent of abdominal pain, and accompanying peritoneal signs.

The clinical presentation of ulcerative colitis depends on whether it is mild, moderate, or severe. Although bleeding is minimal to none in people with mild disease, those with moderate-to-severe ulcerative colitis present with bloody diarrhea with pus, abdominal cramps, and dehydration. Symptoms of weight loss and fever occur in those with severe disease. Patients with Crohn disease usually present with fever, nonbloody diarrhea, and abdominal pain. However, patients with Crohn colitis can present with bloody diarrhea.

Physical

The physical examination should be thorough and include the skin, oropharynx, nasopharynx, abdomen, and anorectum to evaluate for sources of bleeding.

Because brisk UGIB can present as LGIB, a nasogastric tube may be necessary and the aspirate or lavage examined for the presence of blood and bile. An aspirate that is positive for bile is comprehensive in that it includes fluid even beyond the pylorus. In such a scenario, if no blood is present, an UGIB source only makes sense if the bleeding has stopped. If this possibility exists, an esophagogastroduodenoscopy (EGD) should be performed.

Once the bleeding is determined to be from the lower GI tract as opposed to an upper GI source, the tempo of the bleeding and the extent of blood loss should be quickly estimated so that a precise and targeted algorithm is adopted. Patients with massive LGIB usually present with bright red blood per rectum, hypotension, and a markedly reduced hematocrit as opposed to patients with mild bleeding who may present with intermittent passage of maroon-colored stools. The emergency implementation of aggressive resuscitation, diagnostic evaluation, and early involvement of a gastroenterologist (and surgeon in the case of a rapid LGIB) is key to reducing the morbidity and mortality and to improving outcomes.

Causes

Media file 1 outlines the types of LGIB. Common causes of LGIB include diverticular bleeding, angiodysplasia, ischemic colitis, radiation-induced colitis, and other vascular causes. Neoplasms, infectious colitis, idiopathic colitis, anorectal abnormalities, as well as other entities can also cause LGIB.

• Diverticulosis 
• • Diverticulosis is the dominant etiology of LGIB. Most diverticular bleeding occurs without concomitant diverticulitis; diverticulitis does not increase the risk of bleeding.
  • A diverticulum is a saclike protrusion of the colonic wall that develops at a small point of weakness where the penetrating vessel has perforated through the circular muscle fibers. The vessel becomes draped over the dome of the diverticulum, separated from the bowel lumen only by mucosa. Subsequent chronic trauma to the vasa recta along the luminal aspect, as well as contraction and relaxation of the surrounding muscularis propria, leads to eccentric thinning of the media. Ultimately, erosion of the vessel and bleeding can occur. Although 75% of the diverticula occur on the left side of the colon, right-sided diverticula are responsible for 50-90% of the bleeding.⁵ This may be because right-sided diverticula have wider necks and domes, which expose the vasa recta to injury over a greater length.
  • Risk factors for diverticular bleeding include lack of dietary fiber, constipation, advanced age, and NSAID and aspirin use.
• Angiodysplasia  
• • Angiodysplasia is by far the most common vascular anomaly found in the gastrointestinal tract. Lesions can occur anywhere in the gastrointestinal tract; however, they occur most often in the proximal colon. Most colonic angiodysplasias are degenerative lesions that arise from chronic colonic contraction that obstructs the mucosal venous drainage. Over time, mucosal capillaries dilate, become incompetent, and form an arteriovenous malformation. Because bleeding from angiodysplasia is venocapillary in origin, it is generally less vigorous than diverticular bleeding. However, as opposed to diverticular bleeding, about 80% of patients with resolved but untreated angiodysplasia bleeding experience rebleeding.⁶
  • Angiodysplasia is associated with a number of medical conditions, including aortic stenosis, von Willebrand disease, and chronic renal failure. The incidence of angiodysplasia increases with age because of degeneration of the vascular walls. Angiodysplasia was previously believed to be associated with the presence of aortic stenosis, but data supporting this relationship are lacking.
• Ischemic colitis  
• • Ischemic colitis is rarely a cause of significant blood loss; thus, large volume or brisk bleeding should prompt a search for an alternate etiology. Tissue injury is typically caused by hypotension and vasoconstriction, which leads to mucosal friability and endoscopic findings often resembling changes of inflammatory bowel disease. Ischemic colitis usually involves the left side of the colon with rectal sparing.
  • Elderly patients with comorbidities, such as heart failure and arrhythmia, are more susceptible.
• Radiation-induced colitis  
• • Radiation therapy can cause inflammatory changes in the bowel resulting in mucosal telangiectasias that bleed. Radiation therapy for abdominal and pelvic cancers can cause bleeding due to mucosal damage in the colon leading to complications of acute colitis or ulceration. Complications can occur early or late, with a median time of occurrence from 9-15 months.
  • Risk factors for radiation LGIB include arteriosclerosis and concomitant chemotherapy.
• Other vascular causes of LGIB  
• • Vasculitic entities, such as polyarteritis nodosa and Wegener granulomatosis, also can cause LGIB because of the underlying necrotic process that causes sloughing of the mucosa.  Bleeding may also occur secondary to immunosuppressive therapy, which can cause thrombocytopenia.
  • Aortocolonic fistulas that rarely develop after aortic-graft surgery can cause LGIB as much as 10-20 years after surgery.
• Neoplasm  
• • Neoplastic bleeding can be from a polyp or carcinoma. Colon cancer is the predominant cause of neoplastic bleeding and is responsible for 10% of rectal bleeding in patients older than 50 years. The bleeding is usually low-grade and recurrent, occurring as a result of mucosal ulceration or erosion. Though neoplastic bleeding can present as bright red blood per rectum, it is unusual for it to cause massive colonic bleeding.
  • Postpolypectomy bleeding occurs in 0.1-3% of patients, is more often arterial, and can produce significant bleeding. Bleeding can occur at the time of polypectomy but can also manifest several hours to a few weeks after the procedure.
• Infectious colitis  
• • The most common infectious causes of colitis worldwide are Salmonella, Shigella, Campylobacter jejuni, Escherichia coli O157:H7, and Entamoeba histolytica. In the United States, Salmonella, Shigella, and Campylobacter are the most common causative agents. Such microbial agents cause an inflammatory diarrhea characterized by fever, bloody diarrhea, lower quadrant cramps, and tenesmus.
  • The pathophysiological mechanism may be due to either colonic tissue invasion by the bacteria, such as Salmonella and Shigella, or toxin-mediated damage, as with E coli O157:H7. Patients may be quite ill and may experience intravascular volume depletion, abdominal pain, and generalized malaise, but blood loss is usually mild and a minor factor in symptomatology.
• Noninfectious (idiopathic) colitis  
• • Even though inflammatory bowel disease due to Crohn disease or ulcerative colitis causes LGIB, it is rarely massive. Ulcerative colitis can cause mild-to-moderate bloody diarrhea in about 50% of patients, with 4% of patients experiencing massive bleeding. In Crohn disease, massive bleeding is less common and occurs in about 2% of patients with Crohn colitis.
  • The mucosal pattern of injury is similar to that found in patients with infectious and ischemic colitis, with the mucosa appearing friable, erythematous, edematous, and ulcerated. In severe Crohn disease, the inflammatory process may extend into the serosa, leading to colonic perforation.
• Anorectal causes  
• • Anorectal diseases, such as hemorrhoids, fistulas, and fissures, typically cause intermittent rectal bleeding. Hemorrhoidal bleeding is most often painless, whereas bleeding secondary to fissures tends to be painful. Hemorrhoids can also present with strangulation, hematochezia, and pruritus.
  • Typically, bright red blood coats the stool at the end of defecation or blood may stain the toilet paper. Rarely, the bleeding may be copious and distressing to the patient.
• Specific entities causing LGIB  
• • HIV is infrequently a cause of LGIB. Most LGIB in patients with HIV is caused by HIV-related opportunistic infections and associated etiologies.⁷ The major causes of LGIB in patients with HIV include cytomegalovirus (CMV) colitis, idiopathic colon ulcers, Kaposi sarcoma, and lymphoma. Patients with HIV can also bleed from hemorrhoids and anal fissures, where bleeding likelihood is increased due to concomitant coagulopathy.
  • Drug-induced bleeding is caused mainly by NSAID and aspirin use and is more common in the elderly. Although the risk of bleeding increases at higher doses of these agents, even low-dose aspirin given for cardiovascular prophylaxis can produce bleeding. Aspirin or anticoagulants can potentiate or aggravate hemorrhage from preexisting lesions.
• Uncommon causes: Other uncommon causes of LGIB include stercoral ulcer and Dieulafoy lesion of the small or large bowel.

DIFFERENTIALS

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Other Problems to be Considered

See Causes.

WORKUP

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Procedures

• The 3 nonsurgical modalities used to diagnose lower gastrointestinal bleeding (LGIB) are colonoscopy, radionuclide scans, and angiography. Apart from colonoscopy, endoscopic procedures, such as EGD, wireless capsule endoscopy (WCE), push enteroscopy, and double-balloon enteroscopy, are used depending on the clinical circumstance. The sequence of using various modalities depends on such factors as rate of bleeding, hemodynamic status of the patient, and inability to localize bleeding with the initial modality.
• • Colonoscopy: In most patients with LGIB, colonoscopy is the initial diagnostic method of choice. Colonoscopy is successfully used to identify the origin of severe LGIB in 74-82% of patients.⁸ In addition to its diagnostic utility, colonoscopy offers the opportunity for therapeutic intervention in the treatment of vascular ectasias, diverticular bleeding, neoplastic lesions, and ulcerative processes. Thus, colonoscopy tends to result in improved patient outcomes. In patients who are hemodynamically stable with moderate-to-severe bleeding, diagnostic colonoscopy is the test of choice because of its higher diagnostic yield and lower complication rate as compared to angiography.^{9, 10}  
  • • The advantages of colonoscopy include the following: (1) A bleeding lesion is localized in 50-70% of patients. (2) Definitive treatment, such as cautery, injection therapy, or laser photocoagulation, is possible during the procedure. (3) Massively bleeding lesions that have stopped are identified more often with colonoscopy than with angiography.
    • The disadvantages of colonoscopy include the following: (1) Colonoscopy must be performed by skilled endoscopists. (2) Colonoscopy requires a bowel preparation that can cause a 3- to 4-hour delay. (3) A perforation is possible, particularly in a patient who is ill. (4) Colonoscopy carries the risks of sedation for patients who are acutely bleeding. (5) Technical problems can make diagnosis and treatment more difficult.
    • Candidates for colonoscopy should be properly screened and include patients who are hemodynamically stable with no ongoing brisk bleeding because the diagnostic yield is lowered in such patient populations. The bowel should be well prepared, with a rapid oral purge (or via nasogastric tube in selected patients), because performing a colonoscopy on an unprepared bowel is difficult and frequently unsuccessful. The bowel preparation does not reactivate or increase the rate of bleeding. In cases of suspected perforation or obstruction, plain abdominal radiography should be performed prior to colonoscopy to rule out these complications.
  • Radionuclide scans: In patients who are hemodynamically unstable and in patients with brisk ongoing LGIB, an angiography with or without a preceding radionuclide scan can be performed. Radionuclide imaging is more sensitive than angiography but less specific than either endoscopy or angiography. Radionuclide imaging detects bleeding at rates of 0.1-0.5 mL/min as opposed to angiography, which detects bleeding at rates of 1-1.5 mL/min.
  • • Radionuclide scans used include the technetium-99 (99Tc) sulfur colloid scan and the 99mTc pertechnetate–labeled autologous red blood cell scan (TRBC scan). The TRBC scan is preferred because abdominal images can be obtained for up to 24 hours, which is advantageous in patients with intermittent bleeding. TRBC scans detect slow bleeds and have a sensitivity ranging from 80-98%.¹¹ Because of the short half-life and rapid elimination of sulfur colloid, images provided by such scans can be taken for the few minutes that the colloid is in circulation. As a result, such scans may not adequately demonstrate abnormalities in patients with intermittent bleeding.  
    • Advantages for radionuclide scans include the following: (1) Radionuclide scans are noninvasive. (2) Radionuclide scans have a high sensitivity.
    • The disadvantages of radionuclide scans include the following: (1) Scans have a high false localization rate, ranging from 3-59%.¹² (2) Scans must be performed during active bleeding. The difficulty of localization was demonstrated in a study by Hunter et al in which the results of TRBC scanning were incorrect in 25% of patients; 8 patients underwent unwarranted surgical procedures based upon the findings of more definitive tests.¹³ Poor localization of the source of the bleed in radionuclide scans often is due to the overlapping segments of bowel and the migration of tagged red blood cells in the large bowel.
    • Radionuclide scans frequently are performed before angiography because they detect bleeding at a slower rate than what can be detected with angiography, thereby potentially eliminating the need for an invasive procedure. Negative findings on radionuclide scan make subsequent angiography less likely to be of benefit.
  • Angiography: Angiography is performed when active bleeding that precludes colonoscopy occurs and after colonoscopy has failed to identify a bleeding site.  
  • • The advantages of angiography include the following: (1) Angiography provides accurate localization of the bleeding. (2) It has a therapeutic utility that includes the use of vasopressin infusion or embolization. (3) It does not require preparation of the bowel.
    • The disadvantages of angiography include the following: (1) Angiography has sensitivity of 30-47%. (2) It can only be performed during active bleeding. (3) It has a complication rate of 9%. Complications include thrombosis, embolization, and renal failure.¹⁰
    • In angiography, the superior mesenteric artery is first cannulated because most of the hemodynamically significant bleeding originates in the right colon. If the findings from the study are negative, the inferior mesenteric artery is cannulated, followed by the celiac artery. Diverticula, angiodysplasia, and intestinal varices can be visualized by angiography.
  • Upper endoscopy and enteroscopy: An EGD is performed if the nasogastric tube aspirate is positive for blood because 10% of patients presenting with LGIB have bleeding originating from the upper GI tract. Small bowel endoscopic procedures are usually performed after EGD, colonoscopy, radionuclide scans, and angiography have been used and the bleeding site not localized. Small bowel visualization includes the following modalities: (1) WCE, (2) push enteroscopy, (3) enteroclysis, and (4) double-balloon enteroscopy. While no consensus exists on which modality to use initially, WCE is increasingly being used as the test of choice for small bowel bleeding.  
  • • The advantages of WCE include the following: (1) WCE is noninvasive. (2) As opposed to push enteroscopy, WCE permits visualization of most or all of the small bowel. (3) WCE identifies bleeding more often than push enteroscopy.¹⁴
    • Disadvantages of WCE include the following: (1) Retention of the capsule is possible in patients with severe motility disorders and Crohn disease with strictures. (2) No therapeutic capability is possible.
    • Contraindications to WCE include the following: (1) dementia (eg, patients not being able to cooperate with the swallowing of the capsule), (2) esophageal strictures, and (3) partial small bowel obstruction.
  • Although WCE is used as the initial test for small bowel visualization, some experts recommend push enteroscopy as the initial test because of its therapeutic capability. Push enteroscopy is performed with a pediatric colonoscope or a dedicated enteroscope, and once the bleeding site is visualized, it can be treated or tattooed. The main disadvantage of push enteroscopy is that it generally reaches only the proximal 60 cm of the jejunum; bleeding sites beyond that cannot be detected.
  • Enteroclysis, which is a double-contrast study performed by passing a tube into the proximal small bowel and then injecting barium, is avoided in acute bleeding because it may compromise subsequent attempts at endoscopy and angiography. For the same reason, barium studies, such as air contrast barium enemas, are best avoided in acute LGIB.

TREATMENT

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Medical Care

The management of lower gastrointestinal bleeding (LGIB) has 3 components, as follows:

• Resuscitation and initial assessment
• Localization of the bleeding site
• Therapeutic intervention to stop bleeding at the site

Initial resuscitation involves establishing large-bore intravenous access and administration of normal saline. Besides ordering routine lab studies, such as CBC count, electrolytes, and coagulation studies, blood should be typed and cross-matched. The patient's blood loss and hemodynamic status should be ascertained, and in cases of severe bleeding, the patient may require invasive hemodynamic monitoring to direct therapy.

Signs of hemodynamic compromise include postural changes with dyspnea, tachypnea, and tachycardia. An orthostatic drop in systolic blood pressure of more than 10 mm Hg or an increase in heart rate of more than 10 beats per minute is indicative of at least 15% of blood volume loss. A hematocrit level of less than 18% or a decrease of 6% is indicative of significant blood loss that requires blood transfusions; the goal is to achieve a target hematocrit level of 20-25% in young patients and a target hematocrit level of 30% in high-risk, older patients. A coagulopathy, such as an international normalized ratio (INR) of greater than 1.5, may require correction with fresh frozen plasma; thrombocytopenia can be corrected with platelet transfusions.

Patients who require admission to the intensive care unit and early involvement of both a gastroenterologist and a surgeon include the following:

• Patients in shock
• Patients with continuous active bleeding
• Patients at high risk, such as patients with serious comorbidities, those needing multiple blood transfusions, or those with an acute abdomen

In 10% of patients presenting with LGIB, the source of bleeding is from the upper GI tract. Some patients with LGIB should have a nasogastric tube placed, and if the aspirate or lavage does not show any blood, coffee ground–appearing material, but dose show bile, bleeding originating from the upper GI tract is unlikely. In case of high suspicion, an EGD is performed.

In patients who are hemodynamically stable with mild-to-moderate bleeding or in patients who have had a massive bleed that has stabilized, colonoscopy should be performed initially. Once the bleeding site is localized, therapeutic options include coagulation and injection with vasoconstrictors or sclerosing agents. In cases of diverticular bleeding, bipolar probe coagulation, epinephrine injection, and metallic clips may be used. If recurrent bleeding is present, the affected bowel segment can be resected. In cases of angiodysplasia, thermal therapy, such as electrocoagulation or argon plasma coagulation, is generally successful. Angiodysplastic lesions may be missed at colonoscopy if the lesions are small or covered with blood clots.

Colonoscopy is also useful in radiation therapy–induced GI bleeding and in treatment of colonic polyp lesions. Endoscopic treatment of radiation-induced bleeding includes topical application of formalin, Nd:YAG laser therapy, and argon plasma coagulation. Neoplastic bleeding due to polyps requires polypectomy. Patients diagnosed with colonic tumors may require surgical resection.

In patients in whom the bleeding site cannot be determined based on colonoscopy and in patients with active, brisk LGIB, angiography with or without a preceding radionuclide scan should be performed to locate the bleeding site as well as to intervene therapeutically. Therapeutic interventions include vasopressin infusion and embolization performed via a catheter. The bleeding stops in 91% of patients receiving intra-arterial vasopressin but recurs in up to 50% of patients when the infusion is stopped.² In patients with rebleeding, surgery should be considered.

Intra-arterial vasopressin infusions begin at a rate of 0.2 U/min, with repeat angiography performed after 20 minutes. If bleeding persists, the rate of the infusion is increased to 0.4-0.6 U/min. Once the bleeding is controlled, the infusion is continued in an intensive care setting for 12-48 hours and then tapered over the next 24 hours. Vasopressin infusions are more effective in diverticular bleeding, which is arterial, as opposed to angiodysplastic bleeding, which is of the venocapillary type. Complications of vasopressin infusions include myocardial ischemia, hypertension, arrhythmias, hyponatremia, intestinal infarction, and death.¹⁵ Vasopressin infusions are contraindicated in patients with severe coronary artery disease and peripheral artery disease.

Surgical Care

Emergency surgery is required in 10-25% of patients with lower gastrointestinal bleeding (LGIB).¹⁸

The indications for surgery include the following^{8, 4}:

• Persistent hemodynamic instability with active bleeding
• Persistent, recurrent bleeding
• Transfusion of more than 4 units packed red bloods cells in a 24-hour period, with active or recurrent bleeding

Besides the above, factors such as comorbid disease and individual surgical practices play a role in deciding which patient requires surgery.

Patients who are hemodynamically stable should have preoperative localization of the bleeding; patients who are hemodynamically unstable with active bleeding may undergo emergency exploratory laparotomy with intraoperative endoscopy. In patients who are hemodynamically stable, once the bleeding site is preoperatively localized, intra-arterial vasopressin is used as a temporizing measure to reduce the bleeding before patients undergo segmental colectomy. Using this approach the operative morbidity rate is 8.6%, the mortality rate is around 10%, and the rate of rebleed ranges from 0-14%.²

In patients undergoing emergency laparotomy, every attempt should be made to localize the bleeding intraoperatively because a segmental colectomy is preferred. If the bleeding site is not localized, a subtotal colectomy with ileoproctostomy is performed with an inherent morbidity rate of 37% and a mortality rate of 11-33%. Blind segmental colectomy is contraindicated because it has a morbidity rate of up to 83% and a mortality rate as high as 57%.

In a subset of patients, surgery is still required, but with the use of nonsurgical diagnosis and intervention, the morbidity rate has been substantially reduced from 37% to 8.6% in patients undergoing segmental colectomy. With advances in endoscopy and angiography, the rate of preoperative bleeding localization has steadily improved, impacting surgical outcomes in a positive way.

MEDICATION

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The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Posterior pituitary hormones

Agents with vasopressor and antidiuretic hormone activity may reduce LGIB.

FOLLOW-UP

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Further Inpatient Care

• Patients who are hemodynamically unstable with active bleeding should be admitted to the medical intensive care unit (MICU). Early consultation with both a gastroenterologist and a surgeon is recommended.

Further Outpatient Care

• The need for a follow-up colonoscopy is determined by a recurrence of symptoms. Angiodysplasia is more likely to rebleed if untreated and may require follow-up intervention to localize and treat recurrent bleeding. Colonoscopic electrocoagulation is generally successful in such situations.

Complications

• See Treatment.

Prognosis

• Lower gastrointestinal bleeding (LGIB) accounts for up to 24% of all cases of GI bleeding and is associated with significant morbidity and mortality. A thorough history and physical examination will help ascertain the patient's clinical status and aid the physician in determining further treatment.
• The treatment of LGIB includes resuscitation, localizing the bleeding site, and noninvasive or invasive intervention to stop the bleeding. With advances in diagnostic and therapeutic endoscopy and angiography, the ability to localize and subsequently treat LGIB has resulted in improved patient outcomes and reduced health care costs. The need for surgery also has been significantly reduced. The sequence of using these modalities depends on the patient's clinical status, the rate of bleeding, and local expertise in specific surgical and nonsurgical procedures. Using any one modality should not preclude the subsequent use of another modality if required. In case of surgery, preoperative localization of bleeding is essential because segmental colectomies performed after bleeding is localized are associated with the lowest morbidity and mortality.

Patient Education

• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education article Gastrointestinal Bleeding.

MISCELLANEOUS

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Medical/Legal Pitfalls

• An angiogram, which may be preceded by a radionuclide scan, often is performed in patients with active brisk bleeding. While vasopressin helps to stop bleeding in most cases, rebleeding occurs in up to one half of such patients. In these cases, surgery should be considered.
• Every attempt should be made to localize the bleeding site and source in patients undergoing emergency laparotomy. Segmental colectomy can be performed in patients with localized bleeding; subtotal colectomy is performed in patients where bleeding is not localized.
• Blind segmental colectomy is not generally recommended because of the associated high morbidity and mortality.

MULTIMEDIA

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Media file 1:  Types of lower gastrointestinal bleeding (LGIB).
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Media type:  Chart

Media file 2:  Methods used to treat lower gastrointestinal bleeding (LGIB).
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Media type:  Chart

REFERENCES

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• References

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Article Last Updated: Aug 11, 2008